Alcator C-Mod Run 1100225 Information

Miniproposals

Miniproposal: 592

Date Filed: 1/21/2010

Title: L-H Threshold Dependence on Fuelling Location, Density and Neutral Pressure

First Author: Amanda Hubbard

Session Leader: Amanda Hubbard (shots 1-34)

Operators
Session leader(s):	Amanda Hubbard
Physics operator(s):	Ron Parker
Engineering operator(s):	Sam Pierson,Gary Dekow,Ed Fitzgerald

Engineering Operator Run Comment
MP592 - L-H threshold dependence on fueling location, density, & neutral

Session Leader Plans

Entered: Feb 24 2010 06:39:53:063PM

Author: Amanda Hubbard

MP592 - L-H threshold dependence on fueling location, density, & neutral pressure

Session Leader: Amanda Hubbard
Physics Operator: Ron Parker

Request overnight ECDC in Helium.

Require Cryopump available in the morning - probably use all day although we will assess its effect in the first few shots.
NINJA on HFS should be filled with deuterium. (pressure?)

1). Set up target discharge, 800 kA, 5.4 T, Ssep -0.5 cm. Program nel 5e19 m-2, so that we will not get much fuelling from low field side. CRYOPUMP ON.

Shot 1091022024 could be a good starting point for the shape. Check Ip, Ssep programming. Also reduce target density, and adjust the startup for the cryopump.

2) Enable NINJA, starting puff at 0.5 s and leaving on for the flat top. Aim for target nel 0.7 x 1020 m-2, (near typical minimum L-H, to allow comparison with C-Mod database and scalings.) This may take some variation of NINJA pressure. Turn on ICRF 0.7 secs, Increase ICRF power in steps, probably two levels per discharge, find threshold. 3-4 discharges.

3). Repeat with Cryopump OFF, compare neutral pressure and threshold. If no effect, leave off for remaining LSN shots. If it DOES reduce p0, turn on for subsequent discharges. 1-2 discharges.

4. Leave preprogrammed density alone, scan density UP by varying NINJA puff, in coarse steps to start, and finer as pressure increases, to maximum for which MARFE can be avoided and enough ICRF coupled to obtain L-H transition. (eg, approximately nel 0.9, 1.0, 1.1, 1.2, 1.3 x 1020 m-2 ). Use NINJA settings on Steve Wukitch's run 1091023 as a guide to needed pressures. Step RF for each density; expect to need multiple shots per density 12-15 discharges.

5. Turn off NINJA, Switch to LFS gas puffing. Repeat density scan, focusing on nebar 1.5-2 1020 m-3 for which we expect a higher outer midplane neutral pressure, and H-mode access. Select programmed values based on what we obtained in Step 4. Compare L-H thresholds. Anticipate we cannot get as high in ne due to ICRF limits. 10 discharges.

Should we get through all this, continue with other steps in the MP. But I doubt we will. It is critical we get several overlapping points in steps 4 and 5 during the same run day, to answer the first order question of whether there is an effect of fuelling location on the L-H threshold and it is worth continuing another run day. So, we may decide to alternate a few shots each in steps 4 and 5 at the moderate densities to make sure we get this, and to reduce changes in wall loading between the two sets.

Physics Operators Plans

Session Leader Summaries

Entered: Mar 1 2010 10:58:46:960AM

Author: Amanda Hubbard

MP592 - L-H threshold dependence on fueling location, density, & neutral pressure

Session Leader: Amanda Hubbard
Physics Operator: Ron Parker

The main element of this run was to use high field side (HFS) fuelling with the NINJA in RF heated plasmas, following up successful use in high density ohmic plasma in MP xx on Run xxx, which indicated differences in neutral pressure with LFS and HFS fuelling for given density.

The goals of this experiment were

1) To compare L-H thresholds in discharges with HFS and LFS fuelling.
2) To see if the density range with ICRF heated plasmas, and L-H transition densities, could be extended using HFS fuelling (the issue here is the neutral pressure limit for ICRF).
3) If so, see if steady EDA H-modes can be more readily obtained using the higher density.

The machine ran very smoothly today and we accomplished most of the run plan - thanks to excellent physics and engineering operators, and cryopump operators. The cryopump ran so well, and seemed to be beneficial in keeping a level density, that we decided to skip the step of turning it off. Special thanks to Jim Terry for NINJA operation.

The majority of discharges were 5.4 T, 800 kA with ssep -0.5 cm, selected so as to give low L-H threshold but still enable the cryopump to reduce neutral pressure. Many discharges used HFS NINJA puffing, obtained by pre-programming a low target density ( 4 or 5e19 m-2) and then adding a strong NINJA puff; the LFS piezo then closed. NINJA pressure was scanned from 10 to 40 psi, and we obtained target densities between 0.64 and 1.4e20 m-2. ICRF was added in the flat top (typically 0.7 or 0.8 s) and its power stepped to determine L-H thresholds, as evidenced by long delays after turnon. At the lower densities, early in the day, ICRF did cause a small (~ 10e19 m-2) increase in density.

With HFS fuelling, L-H thresholds were remarkably constant, 1.3-1.5 MW, over a wide range of target densities, nel 0.74 (shot 5) to 1.2e20m-2 (Shot 23). Details are in session leader shot comments. At even higher densities, 1.3 and 1.4 e20 (shots 29, 30) L-H transitions were still obtained, with thresholds between 1.8 abnd 2.1 MW. This was the maximum obtainable density with NINJA, though further increases might have been obtained with higher pregrogrammed density. They had clear particle barriers but little or no change in edge temperature.

With LFS fuelling, L-H thresholds were even more frustratingly variable than usual. At nel 0.94e20, threshold was 1.5 MW, the same as with HFS fuelling (shot 10). Shot 16, with very slightly higher density, required 1.9 MW and shot 17, nel 0.99 e20, 2.2 MW indicating a steep upward trend. But, then shots
20 and 21, with higher density (1.18e20 m-3) transitioned to H-mode with only 1.2 MW! This was the upper limit which could be obtained with LFS fuelling - J-port stopped working after 1.0e20 and D and E above 1.2. This is typical of past results.

So, while further detailed analysis is certainly required, in terms of local parameters, neutral pressure etc, the first order answers to the questions seem to be:

1) The L-H power thresholds are variable and not systematically very different with high and low field side fuelling. They do NOT, in either case, follow a simple density scaling.

2) A we had hoped, ICRF operation and L-H transitions can be obtained to higher density with HFS fuelling than with LFS fuelling - limit of at least 1.4e20 m-2 vs 1.2 m-2. Further extension might be possible.

Since 800 kA high density H-modes were not very interesting, for the last few shots of the day we decided to raise Ip (1.1 MA) reducing q95 to 3.1, near the ITER range - though not ITER shape. Note that all shots used a raised x-point to avoid the damaged W tiles.

Shots 32 and 33 were nice examples - in our first attempts, we obtained very steady EDA H-modes with a clear QC mode and nel 2.7 e20 m-2. A pleasant surprise was that all three ICRF antennas performed well at the high density and pressure, with up to 4.75 MW on shot 33. Plasmas were rather cold, with YAG Te0 ~ 1 keV, leading to high collisionality, and global confinement was rather low - near L-Mode.

EDA at this q95 is not unique, but has been hard to obtain routinely. This run suggests that HFS fuelling is a useful technique to achieve high target density H-modes - more shots to optimize heating would be useful, perhaps in the ITER shape once tiles are fixed. One could also try to further decrease q95 - our attempt on the last shot disruptedat q=3, and a low ne locked mode.

Physics Operator Summaries

Entered: Feb 25 2010 04:58:05:707PM

Author: Ron Parker

Great run, as far as the machine was concerned!

Reliable startup, no disruptions, no fizzles and no duds.

For the most part the machine wasn't pushed too hard, with most shots at 800 kA, 5.4 T. Toward the end of the run, current was increased to 1.1 MA and the last few shots ran full length at this current. The most interesting result of the run was production of steady EDA modes at q = 3.15 (shots 32-33)

Scorecard: 34 plasma attempts, 32 full length discharges, 1 hardware failure (Shot 27) and, yes, 1 disruption (at q = 3.)

Session Leader Comments

Feb 25 2010 09:58:25:040AM 1100225001 Amanda Hubbard
Good plasma. 5.46 T, 800 kA. Cryopump ON, no NINJA.

Ssep starts -0.5 cm as we want, drifts up a little.

nel 0.8e19 m-2.

1 MW ICRF, clean, L-Mode.

Feb 25 2010 09:57:36:800AM 1100225002 Amanda Hubbard This shot programmed density was 5e19 m-3; got about 5.6, from C Piezo.

NINJA on at 0.6 s, raised nel only slightly (10 psi).

RF on at 0.8 s, w step at 1.1 s to 2 MW. Notable outgassing during ICRF; nel to 6.9e19. Got H-mode in 2 MW step, so threshold is between 1 and 2 MW.

Ssep -0.5, much steadier. Useful shot.

Feb 25 2010 09:55:54:223AM 1100225003 Amanda Hubbard This shot programmed density was 4e19 m-3. Got 0.43 by 0.5 s

NINJA on at 0.5 s, 15 psi. Piezo turns OFF as we hoped. Gives steady nel 0.63.
C-side MKS 6 mTorr.

RF also moved earlier, request 1.5 MW.

Got L-H transition 0.855 s, (ie fairly long delay) at 1.5 MW. So we are close to the threshold. Drop starting power to 1.25 MW next shot.

Nice Ssep -0.6 s constant until about 1.3 s.

A useful point - keep the plasma the same and nail down threshold.

Feb 25 2010 10:06:29:127AM 1100225004 Amanda Hubbard
No H-mode. RF steps 1.4, 1.6 MW. So threshold is in this range.

nel is 0.63e20 before RF, peaks at 0.78 with RF and then decreases from 1 sec to 0.7. Note that NINJA switches off at 1 sec.

Next shot, extend this to see if density stays steadier. And increase RF slightly to check threshold.

Feb 25 2010 10:43:38:497AM 1100225005 Amanda Hubbard Good threshold point. Delayed H-mode (0.93 s) with 1.5 MW heating.

NINJA fuelling, 15 psi. Cryopump ON (it seems to be working well, and giving steady targets, so I am just going to leave it on rather than spend shots comparing).

nel was 0.65 e20 pre-RF, 0.74 in RF, at L-H transition. Steady, and the RF fuelling seems lower than a few shots ago. A good point to come back to later.

For now, move on to higher nel with NINJA - program 20 psi.

Feb 25 2010 10:35:38:613AM 1100225006 Amanda Hubbard Another good threshold point. Delayed H-mode (1.03 s) with 1.5 MW heating. SO as we half-expected, the threshold is not varying much with nel, near the minimum.

NINJA fuelling, 20 psi. Cryopump ON.

nel was 0.75 e20 pre-RF, 0.89 in RF, at L-H transition.

JT notes that the increase around 0.9 s is the second NINJA puff- which may be overkill in duration.

For next shot, shorten second puff, increase pressure to 25 psi.

Feb 25 2010 10:43:20:057AM 1100225007 Amanda Hubbard
NINJA 25 psi. Got only a slight increase in density (0.81e20 ohmic, 0.87 at L-H with ICRF)

Surprisingly, got an earlier L-H transition, 0.78 s, again with 1.5 MW ICRF.

Next shot, go to 30 psi NINJA for a bigger step in density.

Feb 25 2010 11:00:10:000AM 1100225008 Amanda Hubbard NINJA 30 psi. Got an increase in density (0.87e20 ohmic, 0.96 at L-H with ICRF)

We are still getting an L-H transition, now 0.87 s so quite delayed, in the 1.5 MW RF step. This lack of density dependence is interesting - normally I think PLH would be rising. May indicate a fuelling effect.

Next shot: Reduce RF power to check we have the threshold.

Feb 25 2010 11:14:32:157AM 1100225009 Amanda Hubbard NINJA 30 psi. Got similar increase in density (0.86e20 ohmic, up to 1.0 e20 m-2 with ICRF)

With RF reduced only slightly (1.4 MW) we did NOT get an L-H transition. So 1.5 MW on shot 8 was clearly a good threshold point.

For next shot, turning OFF the NINJA, pre-programming 0.9e20 with normal piezo (LFS). We will compare L-H thresholds (and LFS pressures).

Feb 25 2010 11:35:25:307AM 1100225010 Amanda Hubbard
First comparison shot, with NINJA OFF, programmed nel 0.9 e20 m-2 (ie normal piezo fueling).

Got nel 0.85e20 ohmic, 0.94 with ICRF.

And got a very late L-H transition (1.04 secs) at 1.5 MW ICRF.

So, to first order at least, threshold is the same at this density.

Pressure (F Rat) is 1.7e-4 T at the L-H, only slightly higher than 1.5e-4 on shot 8. Note that it peaks at 2.2e-4 earlier in RF pulse, then drops. Could this be partly why the L-H transition does not occur earlier?

Feb 25 2010 11:44:03:613AM 1100225011 Amanda Hubbard
Back to HFS NINJA fuelling, 35 psi.

Got nel 1.0 to 1.1 e20 m-2, a little variable. Only got 1.3 MW ICRF, no H-mode.

Next shot: Retune, retry. Jim will also adjust pulse length and attemp to smooth out ne time trace.
F-Rat 2.5 to 4e-4.

Feb 25 2010 12:01:11:943PM 1100225012 Amanda Hubbard HFS NINJA fuelling, 35 psi.

Got nel up to 1.2 e20 m-2, max about 1.1 secs.

Got up to 1.36 MW RF. L-H comes late, 1.2 secs, when nel and pressure have started to droop a little. But nel is still 1.17 at L-H, so quite a low threshold.

Feb 25 2010 12:13:50:100PM 1100225013 Amanda Hubbard HFS NINJA fuelling, 35 psi.

nel is lower, with same NINJA - 1.0e20 m-2.

Got an L-H transition in first RF step at 1.5 MW. But it is very gradual/timing indistinct (0.925 s or a bit later?).

Must be close to L-H, given the long delay.

Feb 25 2010 12:29:19:303PM 1100225014 Amanda Hubbard HFS NINJA fuelling, 40 psi. Pulse until 1.0 sec. Gave nice steady nel 1.27 m-2 until 1.0 secs.

ICRF at 1.5 MW did NOT give L-H at this density (finally, some dependence).
DID get L-H at 1.1 secs (very indistinct again) at 1.5 M, and nel 1.2e20.

F-rat was 4.9e-4 at L-H, up to 5.4 at peak.

For next shot, increase RF power and try for H-mode in first phase. Also extend NINJA puff.

Feb 25 2010 12:42:42:133PM 1100225015 Amanda Hubbard HFS NINJA fuelling, 40 psi. Pulse until 1.1 sec. Peak nel 1.2e20, slightly variable - may be some periodic MARFEing.

Got L-H transition in the first RF pulse at 1.6 MW,

Timing, again, is rather indinstict - there are two steps in nel at 0.82, 0.89 s. Resembles D3D "slow transitions". MARFE-related?

F-rat 4.0e-5 before L-H.

Next shot: Turn OFF NINJA, try to repeat this density with normal feedback fuelling. Will RF stay on? Will the threshold change? Stay tuned...

Feb 25 2010 12:56:32:370PM 1100225016 Amanda Hubbard
LFS fueling. Got steady nel of 0.95-0.98 m-2 (lower than prior shots). And L-H threshold is definitely HIGHER. L-H very late, 1.4 secs, and takes 1.9 MW. Did NOT get H-mode at 1.75 MW.

F-Rat is not higher - only 2.5e-4 at L-H. Note that it is actually dropping (from 2.9) just before L-H. A factor in finally transitioning?

The L-H dynamics is quite different - clear jump in nel, unlike the HFS fuelled H-modes.

Next: Increase RF power, try for earier H-mode.

Feb 25 2010 01:10:14:540PM 1100225017 Amanda Hubbard LFS fueling. Repeat nel of 0.95-0.98 m-2

Did NOT get H-mode at 2 MW. Transitioned early in 2.2 MW step. 1.136 s.
So this nicely brackets the threshold power, and is clearly higher than with NINJA at the same nel (which was about 1.5 MW).

nebar is 1.8. Frat 2.26e-4. Still have some headroom.

Increase programmed nel to 1.2e20 m-2.

Feb 25 2010 01:18:01:097PM 1100225018 Amanda Hubbard
Increase programmed nel to 1.2e20 m-2. Got about 1.1e20.

Transitioned right away at 2.2 MW, so apparently not a strong ne dependence.

Frat is 3.5e-4 at L-H.

Increase density demand, want to get into non-linear region. Threshold here is somewhere below 2.2 MW, but presumably at least 2 MW.

Feb 25 2010 01:36:21:150PM 1100225019 Amanda Hubbard Increase programmed nel to 1.3e20 m-2. Got about 1.18e20. Pretty good match to shots 14, 15. But RF (J) now struggling. F-rat is 4.8e-4.

Only 1.3 MW, no L-H until density drops at the end of the flat top (it was programmed down at 1.3).

Try again for more RF from D and E.

Feb 25 2010 01:45:17:207PM 1100225020 Amanda Hubbard Repeat programmed nel 1.3e20 m-2. Got about 1.17e20.

Very low power threshold this time - L-H at 1.04 s, only 1.2 MW!
With D only.

Ratiomatic (I've been using logp_fport) is 4.8 e-4 Torr. So what is different!?

Feb 25 2010 01:51:09:447PM 1100225020 Amanda Hubbard Repeat programmed nel 1.3e20 m-2. Got about 1.17e20.

Very low power threshold this time - L-H at 1.04 s, only 1.2 MW!
With D only.

Ratiomatic (I've been using logp_fport) is 4.8 e-4 Torr. So what is different!?

f-side-rat is 1.27 mTorr.

Feb 25 2010 02:01:33:240PM 1100225021 Amanda Hubbard Repeat shot. With extremely similar, if perplexing, results. Why is threshold so much lower than a few shots ago? J vs D?

Next: raise programmed density.

Feb 25 2010 02:22:37:233PM 1100225022 Amanda Hubbard Raised target to 1.4e20, got 1.26 e 20. At this point neutral pressure is too high for any RF. 1.3-2.1 mTorr.

So, go back to NINJA puffing.

Feb 25 2010 02:31:41:760PM 1100225023 Amanda Hubbard NINJA, 40 psi. Got a nice 1.3 e20 m-2 plasma. nel droops from 1.15 s, we don't get L-H until about 1.25 s, when nel back to 1.2 and RF 1.44 MW.
Fairly consistent with threshold earlier in the day at least.

F-side 1.46 mT max, 1.18 at L-H.

Next, increase RF earlier. And stretch NINJA pulse to avoid the droop.

Feb 25 2010 02:43:41:820PM 1100225024 Amanda Hubbard NINJA, 40 psi. Got a nice density, 1.1 slowly rising to 1.35 e20 m-2.

RF too low (1.3 MW) stayed L-mode. F-side up to 1.7 mTorr.

Feb 25 2010 02:58:36:570PM 1100225025 Amanda Hubbard NINJA, 40 psi. Got a nice density, slowly rising to 1.32 e20 m-2.

No L-H at 1.5 or 1.6 MW. More power, IGOR.

F-side up to 1.8 mT.

Feb 25 2010 03:18:04:840PM 1100225026 Amanda Hubbard NINJA, 40 psi.

Repeat. RF to 1.8 MW, no H-mode.

Feb 25 2010 03:42:12:480PM 1100225028 Amanda Hubbard Raised RF power to 2.3 MW. Got a transition of some kind about 0.98 secs. We'll call it an H-mode, but it is almost entirely in the particle channel - ne_95 clearly jumps, but hardly any change visible in Te (sort of an inverse I-mode).

Next, reduce RF to 2 MW - we know LH threshold between 1.8 and 2.3 at this density.

nel nearly 1.4 e 20 at transition,nel 2.6 e20 - so pretty high for a transition, with modest power. .

Feb 25 2010 03:56:28:180PM 1100225029 Amanda Hubbard Still NINJA at 40 T.

Reduced RF power to 2.1 MW. Still got a transition, a bit clearer, at 0.97 s, nel 1.3e20, nebar 2.5 e 20. This is higher than we are usually able to get at LFS, and not extremely high power. (using D and E only).

F side 1.2 mT, levelling off in H-mode.

Next, try for even higher density by increasing the preprogram.

Feb 25 2010 04:10:44:323PM 1100225030 Amanda Hubbard
Increased starting density. Got marginally higher nel (1.4e20) at the time of the L-H transition. Which still happens at 2.1 MW, 1.01 s.

This is I think higher than we've managed with LFS fuelling (certainly today, we made it to nel 1.17 e20). And it would be hard to increase much further without enormous gas loads.

For last few shots, go to Ip 1.1 MA (q95 near 3) to see if higher target densities are useful operationally in producing steadier H-modes.

Feb 25 2010 04:20:42:880PM 1100225031 Amanda Hubbard Good discharge, 1.1 MA, q95 3.1. nel 1.2 to 1.37 e 20, nebar to 2.5e20.

D and E stayed on OK, to 2.5 MW. But no H-mode. F-side 1.2 mT when RF comes on, peaks at 1.8.

Next: More power, earlier.

Feb 25 2010 04:40:09:700PM 1100225032 Amanda Hubbard

Got a very nice EDA at 1.1 MA, q95=3.1. Clear QC mode. RF 3-4 MW.

nel 1.3e20 m-3 at L-H, steady 2.7e20 in H-mode.
This is lower q95 than we usually obtain EDA.

For shot 33, asked students to reduce second NINJA puff, stopping at 1.0 s since we are in H-mode by then.

Feb 25 2010 04:48:02:100PM 1100225033 Amanda Hubbard Even better EDA at 1.1 MA, q95=3.15. RF 3.5-4.5 MW.
155 kJ.

nel 1.3e20 m-3 at L-H, steady 2.7e20 in H-mode.

F-side peaks at 1.6 mTorr. But Steve reports J is happy, so we will leave the NINJA alone.

Feb 25 2010 04:59:49:223PM 1100225034 Amanda Hubbard Tried for 1.2 MA, but got a locked mode and a q=3 disruption. Worth trying on another run day - likely needed higher early density.

Physics Operator Comments

Feb 24 2010 06:31:03:537PM Ron Parker Engineering Setup for Thursday, 25 February 2010
-----------------
MP592 - L-H threshold dependence on fueling location, density, & neutral pressure

Session Leader: Amanda Hubbard
Physics Operator: Ron Parker

Run begins at 09:00 and ends at 17:00

Power systems as on: 1091022024

Acoil: +Dtop -Dbot -Jtop +Jbot (standard) Hybrid Enabled

Gas setup:

Fill B-Top with 6 psi D2 Hybrid enabled (PG4)
fill B-side lower with 1 psi Ar Hybrid DISABLED (PG1)
leave B-side upper as is Hybrid DISABLED (PG2)
fill B-main (C-side) with 40 psi D2 Hybrid enabled (PG3)
fill H-bottom with 2psi Ne Hybrid DISABLED (PG5)
fill NINJA with 10 psi D2 DISABLED

Enable gatevalves and shutters: ECE, VUV, HiREX Sr, Z-bolo

Torvac gatevalve toggle (yes/no): no

Boronization(yes/no): no
Overnight ECDC (yes/no): yes, standard settings
ICRF(yes/no): yes, Prf = up to 4 MW, all antennas (78 to 80 MHz)
LH(yes/no): no
Cryopump (yes/no): YES, ready for the start of the run

Vessel temperature: 35/35/35

------------------------------
Overnight ECDC Parameters:

Gas: He
sweep: 44/45/103 cm
scan: 20/120 s
Pressure: 5e-5 Torr

Feb 25 2010 09:56:46:300AM 1100225001 Ron Parker Counting down for first shot @ 9:05

Feb 25 2010 09:57:49:693AM 1100225001 Ron Parker Shot 1 ran full length, startup from 1100218030.

Next: reduce density to nel_o4 = 8e19 m-2

Feb 25 2010 09:58:57:180AM 1100225002 Ron Parker Shot 2 ran full length. ZCUR had been reduced by 0.5 mm to try to keep ssep at -0.5 cm -- this seemed to work

Feb 25 2010 09:59:16:350AM 1100225003 Ron Parker Shot 3 ran full length. No PO changes for next shot

Feb 25 2010 10:01:40:400AM 1100225004 Ron Parker Shot 4 ran full length. No PO changes for next shot

Feb 25 2010 10:10:29:550AM 1100225005 Ron Parker Shot 5 ran full length. No PO changes for next shot. Ho hum

Feb 25 2010 10:34:21:547AM 1100225006 Ron Parker Shot 6 ran full length.

Feb 25 2010 10:36:54:770AM 1100225007 Ron Parker Shot 7 ran full length, no PO changes.

Feb 25 2010 10:52:54:880AM 1100225008 Ron Parker Shot 8 ran full length

Feb 25 2010 11:16:26:080AM 1100225009 Ron Parker Shot 9 ran full length.

Next: Ninja off, nel_04 programmed for 0.9e20 m-2.

Feb 25 2010 02:10:14:873PM 1100225010 Ron Parker Shot 10 ran full length.

Next: Reload shot 9, programmed nel_04 =0.4e20 m-2.

Feb 25 2010 12:04:17:243PM 1100225011 Ron Parker Shot 11 ran full length.

Feb 25 2010 12:04:39:200PM 1100225012 Ron Parker Shot 12 ran full length

Feb 25 2010 12:05:08:230PM 1100225013 Ron Parker Shot 13 ran full length

Feb 25 2010 12:19:10:370PM 1100225014 Ron Parker Shot 14 went off as programmed, full length.

Feb 25 2010 12:34:23:107PM 1100225015 Ron Parker Shot 15 ran full length.

I would say that the shots continue to roll, but I don't want to jinx it.

Feb 25 2010 12:38:28:237PM 1100225015 Ron Parker Next: Programmed nel_04 will be set at 1.0e20 m-2.

Feb 25 2010 12:52:13:533PM 1100225016 Ron Parker Shot 16 ran full length

Feb 25 2010 01:03:32:110PM 1100225017 Ron Parker Shot 17 ran full length.

Next: Raise target density to 1.2e20 m-2.

Feb 25 2010 01:17:17:643PM 1100225018 Ron Parker Shot 18 ran full length, but density didn't make it to 1.2e20 m-2.

Next:set programmed density to 1.3e20 m-2.

Feb 25 2010 01:37:25:430PM 1100225019 Ron Parker Shot 19 ran full length, but density programming ramped down before H-mode transition.

We'll extend density programming to 1.4 s.

Feb 25 2010 01:52:09:667PM 1100225020 Ron Parker Shot 20 ran full length.

Next: no change for PO

Feb 25 2010 02:02:02:660PM 1100225021 Ron Parker Shot 21 ran full length.

Next: Set programmed density to 1.4e20 m-2

Feb 25 2010 02:07:34:417PM 1100225022 Ron Parker Another full length shot.

Feb 25 2010 02:13:26:580PM 1100225022 Ron Parker So now it's NINJA's turn to feed the tokamak.

Programmed nel_04=0.4e20 m-2

Feb 25 2010 02:33:21:133PM 1100225023 Ron Parker Shot 23 ran full length.

No change form PO for next shot

Feb 25 2010 02:37:14:267PM 1100225024 Ron Parker Shot 24 ran well, but RF wasn't ready.

Repeat for next shot, waiting for RF to be ready.

Feb 25 2010 02:59:16:990PM 1100225025 Ron Parker Shot 25 ran full length.

No PO changes for next shot.

Feb 25 2010 03:07:35:330PM 1100225026 Ron Parker Same story, full length shot.

Feb 25 2010 03:27:27:650PM 1100225027 Ron Parker Failure in EF1 Upper circuit. Commutated early. No plasma.

We'll run the shot again.

Feb 25 2010 03:31:14:310PM 1100225028 Ron Parker OK, the shot is back.

Feb 25 2010 03:49:09:580PM 1100225029 Ron Parker Shot 29 ran, and ran full length.

Next: increase programmed nel_04 to 6e19 m-2.

Feb 25 2010 04:04:31:410PM 1100225030 Ron Parker Shot 30 ran full length

Next: Increase i_p to 1.1 MA

Feb 25 2010 04:15:29:360PM 1100225031 Ron Parker Shot 31 ran full length, low RF power.

Next: Igor is asked for more power.

Feb 25 2010 04:27:54:763PM 1100225032 Ron Parker Shot 32 ran full length.

Mar 10 2010 04:43:00:263PM 1100225033 Ron Parker Ran full length at 1.1 MA

Mar 10 2010 04:44:06:607PM 1100225034 Ron Parker Went for 1.2 MA, but plasma disrupted as q passed through 3

Engineering Operator Comments

Shot Time Type Status Comment

1 09:06:24:760AM Plasma Ok

2 09:23:38:747AM Plasma Ok

3 09:37:38:390AM Plasma Ok

4 09:51:48:827AM Plasma Ok

5 10:05:00:200AM Plasma Ok

6 10:18:04:983AM Plasma Ok

7 10:32:19:013AM Plasma Ok

8 10:49:18:377AM Plasma Ok

9 11:02:47:643AM Plasma Ok

10 11:19:53:303AM Plasma Ok

11 11:33:34:523AM Plasma Ok

12 11:47:08:367AM Plasma Ok

13 12:00:16:897PM Plasma Ok

14 12:14:50:553PM Plasma Ok

15 12:29:31:290PM Plasma Ok

16 12:43:14:917PM Plasma Ok

17 12:56:31:087PM Plasma Ok

18 01:09:55:040PM Plasma Ok

19 01:23:20:460PM Plasma Ok

20 01:36:34:570PM Plasma Ok

21 01:51:44:713PM Plasma Ok

22 02:05:17:430PM Plasma Ok

23 02:19:23:353PM Plasma Ok

24 02:33:32:347PM Plasma Ok

25 02:47:22:423PM Plasma Ok

26 03:01:18:087PM Plasma Ok

27 03:15:13:743PM Plasma Bad EF1L commutation problem

28 03:28:51:713PM Plasma Ok

29 03:42:02:743PM Plasma Ok

30 03:55:10:447PM Plasma Ok

31 04:08:53:367PM Plasma Ok

32 04:23:06:557PM Plasma Ok

33 04:37:57:760PM Plasma Ok

34 04:51:09:137PM Plasma Ok

System Availability

Feb 25 2010 09:05:44:947AM

System Available Comment Availability
Changed Owner Description Who Can
Change
Active MHD no secured - tagged out Jun 02 2008 11:03AM (sears) Joe Snipes Active MHD Antenna sears,snipes
BES yes 7 horizontal views spread out R_maj=[0.72-0.9m], 3 cm over the tokamak midplane (beam) Jul 09 2009 05:12PM (bespam) Bill Rowan Beam Emission Spectroscopy bespam,liao,rowan
Bolometers yes 2pi (diode+foil), AXA, AXJ, WB3AX, WB4AX, LEDGE-AX working fine. MID-FOILS working fine. The LEDGE/DIV foils still need calibrations applied Aug 27 2009 09:09AM (mlreinke) Matt Reinke Bolometers hutch,mlreinke
Boronization yes Nov 13 2009 06:37AM (dekow) Jim Irby Boronization dekow,irby
CNPA no Single channel CNPA available as of 12/1707 Jun 10 2009 10:22AM (twf) Ron Parker Compact Neutral Analyzer parker
Cryopump - Upper Divertor yes Operational Nov 09 2009 09:12AM (irby) Brian LaBombard Upper Divertor Cryopump irby,labombard
CXRS yes The wide-view toroidal array was installed, spatially and absolutely calibrated. There are 7 toroidal chords intersect the beam at the major_R_range=[74.2:83.6]cm. Spatial resolution: 1.2 cm. The F-top wide-view poloidal array was installed and spatially calibrated. There are 19 chords intersect the beam at the major_R_range=[0.65:0.9.]m. Spatial resolution: 1.22 cm. Jul 09 2009 05:16PM (bespam) Bill Rowan Charge Exchange Spectroscopy bespam,blip,liao,rachmcd,rowan
D Alpha yes \ha2_bright is available; \SPECTROSCOPY::TOP.VUV.VIS_SIGNALS:MCP_VIS_SIG1 is not available Jul 01 2009 09:45AM (terry) Jim Terry Balmer Alpha Monitor irby,terry,wolfe
Dalsa yes system is aligned and operating; not yet calibrated Jul 14 2009 02:22PM (marmar) Earl Marmar Visible Bremsstrahlung marmar
Disruption Mitigation yes operational, but turned off Nov 03 2009 04:59PM (granetz) Robert Granetz Gas Jet granetz,whyte
Divertor IR no Mar 06 2007 10:50AM Glen Wurden Divertor IR Digital Video gwurden,terry
Divertor IR Spectroscopy no Mar 06 2007 10:51AM Glen Wurden Divertor IR Spectroscopy gwurden,terry
DNB no in test mode only Nov 03 2009 05:01PM (granetz) Robert Granetz Diagnostic Neutral Beam dterry,granetz,gung
ECDC yes Nov 09 2009 09:13AM (irby) Jim Irby 2.45 GHz, 3 kW, discharge cleaning system dekow,irby,pfeiffer
FRC-ECE yes All channels working and calibrated. Feb 02 2010 09:56AM (phillips) Perry Phillips Heterodyne ECE-32 channels phillips
G-Side Ratiomatic yes Gauge installed. Controller repaired. Aug 23 2009 10:36PM (toland) Brian LaBombard G-side ratiomatic ionization gauge labombard,toland
Glow Discharge no 6/10/09: Paddles meggered at 1000 v to machine ground (>300 Mohm) prior to closing the vacuum chamber. Plugs for Power Supply and Controls Unplugged and Red Tagged, Safe for In-Vessel Access Jun 10 2009 01:47PM (dekow) Jim Irby 1 kV, 5 A, glow discharge system dekow,dterry,irby
GPC yes Operational. Jul 28 2009 04:23PM (hubbard) Amanda Hubbard ECE Polychromater hubbard,schmidt
GPC2 yes Most channels operational. Jul 28 2009 04:23PM (hubbard) Amanda Hubbard ECE Polychromater hubbard,schmidt
GPI yes The Xpt-view, the midplane-view cameras are operational. The innerwall GPI (coupled to the fast-diodes) is available. Jul 01 2009 09:45AM (terry) Jim Terry Gas Puff Imaging terry,zweben
H/D yes poses no safety hazard for people working around the machine Jun 18 2009 01:04PM (marmar) Earl Marmar H/D Ratio marmar
HEAT yes Oct 27 2009 10:39AM (dekow) Gary Dekow - Machine Heaters - burke,dekow
Hirex Jr yes Hirex-Jr has been installed and tested Jun 17 2009 11:54AM (rice) John Rice High Resolution X-Ray ince,rice
Hirex Sr yes currently only one detector is operational, off-axis He-like argon emission Jul 14 2009 10:01AM (rice) John Rice High Resolution X-Ray ince,rice
HXR no In safe mode (high voltage turned off) May 27 2008 09:19PM (schmidt) Ron Parker Hard X-Ray Array parker,schmidt
ICRF D-Antenna yes operational at 80 MHz Jul 21 2009 04:49PM (wukitch) Steve Wukitch D-port antenna wukitch,ylin
ICRF E-Antenna yes antenna and FFT operational Jul 21 2009 04:49PM (wukitch) Steve Wukitch E-port antenna wukitch,ylin
ICRF J-Antenna yes available at 80 MHz and [0,pi,0,pi] phasing Sep 04 2009 10:01AM (wukitch) Steve Wukitch J-port antenna wukitch,ylin
Laser Blow-Off yes Requires some advance notice for laser start-up Oct 16 2009 12:46PM (g) Martin Greenwald Impurity Injection System g,nthoward
Lower Hybrid no Breaker locked and tagged out. Waveguide disassembly started. Open Waveguides have been shorted. May 28 2008 09:47AM (dterry) Ron Parker Lower Hybrid dterry,parker,wallaceg
LPI no Beam line removed May 30 2008 02:09PM (bose) Earl Marmar Lithium Pellet Injector bose,marmar
Ly-alpha yes Midplane, WB4-LY, LEDGE-LY all collecting data. WB1-LY not attached. Aug 27 2009 09:10AM (mlreinke) Matt Reinke Lyman alpha cameras labombard,mlreinke
McPherson yes Operating normally Aug 27 2009 09:10AM (mlreinke) Jim Terry VUV Spectrometer mlreinke,terry
Michelson yes Operational. Recalibrated 7/27/09. Jul 28 2009 04:22PM (hubbard) Amanda Hubbard ECE Te Profiles hubbard,schmidt
MKS yes Gauges are on. B-bottom is not operating - bad sensor head? Jul 14 2009 09:12PM (labombard) Brian LaBombard Baratron pressure gauges labombard
MLP no System is in edge lab. Version 2 drivers ready to test. Needs a student to help work on it. Jul 14 2009 09:20PM (labombard) Brian LaBombard Mirror Langmuir Probe Electronics System labombard
MSE no As of 6/10/09, MSE is calibrated & ready to go. Awaiting DNB. Jun 10 2009 10:34AM (sscott) Steve Scott Motional Stark Effect jinseok,sscott
Neutrons yes Neutron detectors are calibrated and ready to go. Voltages will be turned on prior to first plasma. Jun 10 2009 10:35AM (fiore) Catherine Fiore Neutron Detectors fiore
Neuts and Hards yes Power back on morning of 11/09 before run Nov 09 2009 09:10AM (irby) Jim Irby X-Ray/Neutron Detector at K-Hor irby
NINJA no Capillaries were tested in-vessel. Plenum has a leak and needs fixing. Jul 14 2009 09:14PM (labombard) Brian LaBombard NINJA gas puff labombard,terry
PCI yes Operational. Nov 12 2009 02:36PM (ntsujii) Miklos Porkolab Phase Contrast Imaging arai,ennever,ntsujii,porkolab
Penning Gauges yes High voltage is enabled (on during INIT, off during RECOOL). Jun 30 2009 09:42PM (labombard) Brian LaBombard Penning Ionization Gauges labombard
Plasma TV yes WIDE1, WIDE2 (chan 33), DANT, JANT and DIV are operational. Jul 01 2009 09:46AM (terry) Jim Terry Video of plasma via several cameras dekow,irby,terry,wolfe
Polarimeter no Safe for Machine Entry Sep 14 2007 12:17PM (irby) Jim Irby C-Mod Polarimeter irby
Power - Alternator Air Switch yes Checked and Operational as of 06/18/09 Jun 19 2009 08:04AM (irby) Gary Dekow feeds all the other supplies cochran,dekow,dterry,irby
Power - PEI yes Nov 13 2009 06:38AM (dekow) Gary Dekow PEI System cochran,dekow,dterry,irby
Power - TMX yes Checked out and ready for Magnet Tests as of 06/18/09 Jun 19 2009 08:07AM (irby) Gary Dekow Ef2s,. EFCs and A-Coils byford,cochran,dekow,dterry,irby
Power Systems yes Checked out and ready for Magnet Tests as of 06/18/09 Jun 19 2009 08:07AM (irby) Jim Irby C-Mod Magnet Supplies byford,cochran,dekow,dterry,irby
Probe Array - ISD yes Array is operational with new cPCI data system. Probe 14 has open circuit. Jul 14 2009 09:17PM (labombard) Brian Labombard Inner Lower Divertor Probe Array labombard
Probe Array - LH no LH launcher not installed. Cables are unplugged at the A-port rack. Jul 14 2009 09:16PM (labombard) Brian LaBombard Lower Hybrid Probe Array labombard
Probe Array - OSD yes Array is operational with new cPCI data system. Jul 14 2009 09:16PM (labombard) Brian LaBombard Outer Lower Divertor Probe Array labombard
Probe Array - UDIV yes Array is operational with new cPCI data system. Probe 13 has a bad cable (open). Jul 14 2009 09:17PM (labombard) Brian LaBombard Upper Divertor Probe Array labombard
Reflectometer yes Since 1100120000 the system is operational except for channel 110 which is not installed Jan 20 2010 09:17AM (dominguez) Earl Marmar Reflectometer dominguez,marmar
Scanning Probe - ASP yes Probe is operational. Needs plasma conditioning. Jul 14 2009 09:18PM (labombard) Brian LaBombard A-Port Scanning Probe labombard
Scanning Probe - FSP yes Probe is operational. Needs plasma conditioning. Jul 14 2009 09:18PM (labombard) Brian LaBombard F-Port Scanning Probe labombard
Scanning Probe - WASP yes System connected to A-port WASP. Needs plasma testing. Jul 14 2009 09:19PM (labombard) Brian LaBombard Inner Wall Scanning Probe labombard,nsmick
Sparker yes Sparker back in operation before 11/09 run Nov 09 2009 09:11AM (irby) Jim Irby Field Emission Preionization for C-Mod dekow,irby,parkin
TCI yes System restarted and aligned. Several chords available including NL04. Density Feedback available. Ready for plasma. Jun 18 2009 09:15AM (murray) Jim Irby Two-Color Interferometer irby,murray
TS - Core yes 2 lasers working. 15 spatial channels operational. Calibrated Oct 13 2009 07:49PM (yma) Jerry Hughes Core Thomson scattering jwhughes,yma,zhang
TS - Edge yes Operational, and calibrated. Oct 11 2009 03:01PM (jwhughes) Jerry Hughes Millimeter resolution edge Thomson scattering jwhughes,yma,zhang
Vispec no 350 and 670 nm, 4 spatial channels Nov 28 2007 09:58AM (agraf) Alex Graf Visible Spectrometer agraf
XTOMO yes Operating normally Aug 27 2009 09:10AM (mlreinke) Bob Granetz X-Ray Tomography granetz,mlreinke

Session Leader Comments
Feb 25 2010 09:58:25:040AM	1100225001	Amanda Hubbard	Good plasma. 5.46 T, 800 kA. Cryopump ON, no NINJA. Ssep starts -0.5 cm as we want, drifts up a little. nel 0.8e19 m-2. 1 MW ICRF, clean, L-Mode.
Feb 25 2010 09:57:36:800AM	1100225002	Amanda Hubbard	This shot programmed density was 5e19 m-3; got about 5.6, from C Piezo. NINJA on at 0.6 s, raised nel only slightly (10 psi). RF on at 0.8 s, w step at 1.1 s to 2 MW. Notable outgassing during ICRF; nel to 6.9e19. Got H-mode in 2 MW step, so threshold is between 1 and 2 MW. Ssep -0.5, much steadier. Useful shot.
Feb 25 2010 09:55:54:223AM	1100225003	Amanda Hubbard	This shot programmed density was 4e19 m-3. Got 0.43 by 0.5 s NINJA on at 0.5 s, 15 psi. Piezo turns OFF as we hoped. Gives steady nel 0.63. C-side MKS 6 mTorr. RF also moved earlier, request 1.5 MW. Got L-H transition 0.855 s, (ie fairly long delay) at 1.5 MW. So we are close to the threshold. Drop starting power to 1.25 MW next shot. Nice Ssep -0.6 s constant until about 1.3 s. A useful point - keep the plasma the same and nail down threshold.
Feb 25 2010 10:06:29:127AM	1100225004	Amanda Hubbard	No H-mode. RF steps 1.4, 1.6 MW. So threshold is in this range. nel is 0.63e20 before RF, peaks at 0.78 with RF and then decreases from 1 sec to 0.7. Note that NINJA switches off at 1 sec. Next shot, extend this to see if density stays steadier. And increase RF slightly to check threshold.
Feb 25 2010 10:43:38:497AM	1100225005	Amanda Hubbard	Good threshold point. Delayed H-mode (0.93 s) with 1.5 MW heating. NINJA fuelling, 15 psi. Cryopump ON (it seems to be working well, and giving steady targets, so I am just going to leave it on rather than spend shots comparing). nel was 0.65 e20 pre-RF, 0.74 in RF, at L-H transition. Steady, and the RF fuelling seems lower than a few shots ago. A good point to come back to later. For now, move on to higher nel with NINJA - program 20 psi.
Feb 25 2010 10:35:38:613AM	1100225006	Amanda Hubbard	Another good threshold point. Delayed H-mode (1.03 s) with 1.5 MW heating. SO as we half-expected, the threshold is not varying much with nel, near the minimum. NINJA fuelling, 20 psi. Cryopump ON. nel was 0.75 e20 pre-RF, 0.89 in RF, at L-H transition. JT notes that the increase around 0.9 s is the second NINJA puff- which may be overkill in duration. For next shot, shorten second puff, increase pressure to 25 psi.
Feb 25 2010 10:43:20:057AM	1100225007	Amanda Hubbard	NINJA 25 psi. Got only a slight increase in density (0.81e20 ohmic, 0.87 at L-H with ICRF) Surprisingly, got an earlier L-H transition, 0.78 s, again with 1.5 MW ICRF. Next shot, go to 30 psi NINJA for a bigger step in density.
Feb 25 2010 11:00:10:000AM	1100225008	Amanda Hubbard	NINJA 30 psi. Got an increase in density (0.87e20 ohmic, 0.96 at L-H with ICRF) We are still getting an L-H transition, now 0.87 s so quite delayed, in the 1.5 MW RF step. This lack of density dependence is interesting - normally I think PLH would be rising. May indicate a fuelling effect. Next shot: Reduce RF power to check we have the threshold.
Feb 25 2010 11:14:32:157AM	1100225009	Amanda Hubbard	NINJA 30 psi. Got similar increase in density (0.86e20 ohmic, up to 1.0 e20 m-2 with ICRF) With RF reduced only slightly (1.4 MW) we did NOT get an L-H transition. So 1.5 MW on shot 8 was clearly a good threshold point. For next shot, turning OFF the NINJA, pre-programming 0.9e20 with normal piezo (LFS). We will compare L-H thresholds (and LFS pressures).
Feb 25 2010 11:35:25:307AM	1100225010	Amanda Hubbard	First comparison shot, with NINJA OFF, programmed nel 0.9 e20 m-2 (ie normal piezo fueling). Got nel 0.85e20 ohmic, 0.94 with ICRF. And got a very late L-H transition (1.04 secs) at 1.5 MW ICRF. So, to first order at least, threshold is the same at this density. Pressure (F Rat) is 1.7e-4 T at the L-H, only slightly higher than 1.5e-4 on shot 8. Note that it peaks at 2.2e-4 earlier in RF pulse, then drops. Could this be partly why the L-H transition does not occur earlier?
Feb 25 2010 11:44:03:613AM	1100225011	Amanda Hubbard	Back to HFS NINJA fuelling, 35 psi. Got nel 1.0 to 1.1 e20 m-2, a little variable. Only got 1.3 MW ICRF, no H-mode. Next shot: Retune, retry. Jim will also adjust pulse length and attemp to smooth out ne time trace. F-Rat 2.5 to 4e-4.
Feb 25 2010 12:01:11:943PM	1100225012	Amanda Hubbard	HFS NINJA fuelling, 35 psi. Got nel up to 1.2 e20 m-2, max about 1.1 secs. Got up to 1.36 MW RF. L-H comes late, 1.2 secs, when nel and pressure have started to droop a little. But nel is still 1.17 at L-H, so quite a low threshold.
Feb 25 2010 12:13:50:100PM	1100225013	Amanda Hubbard	HFS NINJA fuelling, 35 psi. nel is lower, with same NINJA - 1.0e20 m-2. Got an L-H transition in first RF step at 1.5 MW. But it is very gradual/timing indistinct (0.925 s or a bit later?). Must be close to L-H, given the long delay.
Feb 25 2010 12:29:19:303PM	1100225014	Amanda Hubbard	HFS NINJA fuelling, 40 psi. Pulse until 1.0 sec. Gave nice steady nel 1.27 m-2 until 1.0 secs. ICRF at 1.5 MW did NOT give L-H at this density (finally, some dependence). DID get L-H at 1.1 secs (very indistinct again) at 1.5 M, and nel 1.2e20. F-rat was 4.9e-4 at L-H, up to 5.4 at peak. For next shot, increase RF power and try for H-mode in first phase. Also extend NINJA puff.
Feb 25 2010 12:42:42:133PM	1100225015	Amanda Hubbard	HFS NINJA fuelling, 40 psi. Pulse until 1.1 sec. Peak nel 1.2e20, slightly variable - may be some periodic MARFEing. Got L-H transition in the first RF pulse at 1.6 MW, Timing, again, is rather indinstict - there are two steps in nel at 0.82, 0.89 s. Resembles D3D "slow transitions". MARFE-related? F-rat 4.0e-5 before L-H. Next shot: Turn OFF NINJA, try to repeat this density with normal feedback fuelling. Will RF stay on? Will the threshold change? Stay tuned...
Feb 25 2010 12:56:32:370PM	1100225016	Amanda Hubbard	LFS fueling. Got steady nel of 0.95-0.98 m-2 (lower than prior shots). And L-H threshold is definitely HIGHER. L-H very late, 1.4 secs, and takes 1.9 MW. Did NOT get H-mode at 1.75 MW. F-Rat is not higher - only 2.5e-4 at L-H. Note that it is actually dropping (from 2.9) just before L-H. A factor in finally transitioning? The L-H dynamics is quite different - clear jump in nel, unlike the HFS fuelled H-modes. Next: Increase RF power, try for earier H-mode.
Feb 25 2010 01:10:14:540PM	1100225017	Amanda Hubbard	LFS fueling. Repeat nel of 0.95-0.98 m-2 Did NOT get H-mode at 2 MW. Transitioned early in 2.2 MW step. 1.136 s. So this nicely brackets the threshold power, and is clearly higher than with NINJA at the same nel (which was about 1.5 MW). nebar is 1.8. Frat 2.26e-4. Still have some headroom. Increase programmed nel to 1.2e20 m-2.
Feb 25 2010 01:18:01:097PM	1100225018	Amanda Hubbard	Increase programmed nel to 1.2e20 m-2. Got about 1.1e20. Transitioned right away at 2.2 MW, so apparently not a strong ne dependence. Frat is 3.5e-4 at L-H. Increase density demand, want to get into non-linear region. Threshold here is somewhere below 2.2 MW, but presumably at least 2 MW.
Feb 25 2010 01:36:21:150PM	1100225019	Amanda Hubbard	Increase programmed nel to 1.3e20 m-2. Got about 1.18e20. Pretty good match to shots 14, 15. But RF (J) now struggling. F-rat is 4.8e-4. Only 1.3 MW, no L-H until density drops at the end of the flat top (it was programmed down at 1.3). Try again for more RF from D and E.
Feb 25 2010 01:45:17:207PM	1100225020	Amanda Hubbard	Repeat programmed nel 1.3e20 m-2. Got about 1.17e20. Very low power threshold this time - L-H at 1.04 s, only 1.2 MW! With D only. Ratiomatic (I've been using logp_fport) is 4.8 e-4 Torr. So what is different!?
Feb 25 2010 01:51:09:447PM	1100225020	Amanda Hubbard	Repeat programmed nel 1.3e20 m-2. Got about 1.17e20. Very low power threshold this time - L-H at 1.04 s, only 1.2 MW! With D only. Ratiomatic (I've been using logp_fport) is 4.8 e-4 Torr. So what is different!? f-side-rat is 1.27 mTorr.
Feb 25 2010 02:01:33:240PM	1100225021	Amanda Hubbard	Repeat shot. With extremely similar, if perplexing, results. Why is threshold so much lower than a few shots ago? J vs D? Next: raise programmed density.
Feb 25 2010 02:22:37:233PM	1100225022	Amanda Hubbard	Raised target to 1.4e20, got 1.26 e 20. At this point neutral pressure is too high for any RF. 1.3-2.1 mTorr. So, go back to NINJA puffing.
Feb 25 2010 02:31:41:760PM	1100225023	Amanda Hubbard	NINJA, 40 psi. Got a nice 1.3 e20 m-2 plasma. nel droops from 1.15 s, we don't get L-H until about 1.25 s, when nel back to 1.2 and RF 1.44 MW. Fairly consistent with threshold earlier in the day at least. F-side 1.46 mT max, 1.18 at L-H. Next, increase RF earlier. And stretch NINJA pulse to avoid the droop.
Feb 25 2010 02:43:41:820PM	1100225024	Amanda Hubbard	NINJA, 40 psi. Got a nice density, 1.1 slowly rising to 1.35 e20 m-2. RF too low (1.3 MW) stayed L-mode. F-side up to 1.7 mTorr.
Feb 25 2010 02:58:36:570PM	1100225025	Amanda Hubbard	NINJA, 40 psi. Got a nice density, slowly rising to 1.32 e20 m-2. No L-H at 1.5 or 1.6 MW. More power, IGOR. F-side up to 1.8 mT.
Feb 25 2010 03:18:04:840PM	1100225026	Amanda Hubbard	NINJA, 40 psi. Repeat. RF to 1.8 MW, no H-mode.
Feb 25 2010 03:42:12:480PM	1100225028	Amanda Hubbard	Raised RF power to 2.3 MW. Got a transition of some kind about 0.98 secs. We'll call it an H-mode, but it is almost entirely in the particle channel - ne_95 clearly jumps, but hardly any change visible in Te (sort of an inverse I-mode). Next, reduce RF to 2 MW - we know LH threshold between 1.8 and 2.3 at this density. nel nearly 1.4 e 20 at transition,nel 2.6 e20 - so pretty high for a transition, with modest power. .
Feb 25 2010 03:56:28:180PM	1100225029	Amanda Hubbard	Still NINJA at 40 T. Reduced RF power to 2.1 MW. Still got a transition, a bit clearer, at 0.97 s, nel 1.3e20, nebar 2.5 e 20. This is higher than we are usually able to get at LFS, and not extremely high power. (using D and E only). F side 1.2 mT, levelling off in H-mode. Next, try for even higher density by increasing the preprogram.
Feb 25 2010 04:10:44:323PM	1100225030	Amanda Hubbard	Increased starting density. Got marginally higher nel (1.4e20) at the time of the L-H transition. Which still happens at 2.1 MW, 1.01 s. This is I think higher than we've managed with LFS fuelling (certainly today, we made it to nel 1.17 e20). And it would be hard to increase much further without enormous gas loads. For last few shots, go to Ip 1.1 MA (q95 near 3) to see if higher target densities are useful operationally in producing steadier H-modes.
Feb 25 2010 04:20:42:880PM	1100225031	Amanda Hubbard	Good discharge, 1.1 MA, q95 3.1. nel 1.2 to 1.37 e 20, nebar to 2.5e20. D and E stayed on OK, to 2.5 MW. But no H-mode. F-side 1.2 mT when RF comes on, peaks at 1.8. Next: More power, earlier.
Feb 25 2010 04:40:09:700PM	1100225032	Amanda Hubbard	Got a very nice EDA at 1.1 MA, q95=3.1. Clear QC mode. RF 3-4 MW. nel 1.3e20 m-3 at L-H, steady 2.7e20 in H-mode. This is lower q95 than we usually obtain EDA. For shot 33, asked students to reduce second NINJA puff, stopping at 1.0 s since we are in H-mode by then.
Feb 25 2010 04:48:02:100PM	1100225033	Amanda Hubbard	Even better EDA at 1.1 MA, q95=3.15. RF 3.5-4.5 MW. 155 kJ. nel 1.3e20 m-3 at L-H, steady 2.7e20 in H-mode. F-side peaks at 1.6 mTorr. But Steve reports J is happy, so we will leave the NINJA alone.
Feb 25 2010 04:59:49:223PM	1100225034	Amanda Hubbard	Tried for 1.2 MA, but got a locked mode and a q=3 disruption. Worth trying on another run day - likely needed higher early density.

Physics Operator Comments
Feb 24 2010 06:31:03:537PM		Ron Parker	Engineering Setup for Thursday, 25 February 2010 ----------------- MP592 - L-H threshold dependence on fueling location, density, & neutral pressure Session Leader: Amanda Hubbard Physics Operator: Ron Parker Run begins at 09:00 and ends at 17:00 Power systems as on: 1091022024 Acoil: +Dtop -Dbot -Jtop +Jbot (standard) Hybrid Enabled Gas setup: Fill B-Top with 6 psi D2 Hybrid enabled (PG4) fill B-side lower with 1 psi Ar Hybrid DISABLED (PG1) leave B-side upper as is Hybrid DISABLED (PG2) fill B-main (C-side) with 40 psi D2 Hybrid enabled (PG3) fill H-bottom with 2psi Ne Hybrid DISABLED (PG5) fill NINJA with 10 psi D2 DISABLED Enable gatevalves and shutters: ECE, VUV, HiREX Sr, Z-bolo Torvac gatevalve toggle (yes/no): no Boronization(yes/no): no Overnight ECDC (yes/no): yes, standard settings ICRF(yes/no): yes, Prf = up to 4 MW, all antennas (78 to 80 MHz) LH(yes/no): no Cryopump (yes/no): YES, ready for the start of the run Vessel temperature: 35/35/35 ------------------------------ Overnight ECDC Parameters: Gas: He sweep: 44/45/103 cm scan: 20/120 s Pressure: 5e-5 Torr
Feb 25 2010 09:56:46:300AM	1100225001	Ron Parker	Counting down for first shot @ 9:05
Feb 25 2010 09:57:49:693AM	1100225001	Ron Parker	Shot 1 ran full length, startup from 1100218030. Next: reduce density to nel_o4 = 8e19 m-2
Feb 25 2010 09:58:57:180AM	1100225002	Ron Parker	Shot 2 ran full length. ZCUR had been reduced by 0.5 mm to try to keep ssep at -0.5 cm -- this seemed to work
Feb 25 2010 09:59:16:350AM	1100225003	Ron Parker	Shot 3 ran full length. No PO changes for next shot
Feb 25 2010 10:01:40:400AM	1100225004	Ron Parker	Shot 4 ran full length. No PO changes for next shot
Feb 25 2010 10:10:29:550AM	1100225005	Ron Parker	Shot 5 ran full length. No PO changes for next shot. Ho hum
Feb 25 2010 10:34:21:547AM	1100225006	Ron Parker	Shot 6 ran full length.
Feb 25 2010 10:36:54:770AM	1100225007	Ron Parker	Shot 7 ran full length, no PO changes.
Feb 25 2010 10:52:54:880AM	1100225008	Ron Parker	Shot 8 ran full length
Feb 25 2010 11:16:26:080AM	1100225009	Ron Parker	Shot 9 ran full length. Next: Ninja off, nel_04 programmed for 0.9e20 m-2.
Feb 25 2010 02:10:14:873PM	1100225010	Ron Parker	Shot 10 ran full length. Next: Reload shot 9, programmed nel_04 =0.4e20 m-2.
Feb 25 2010 12:04:17:243PM	1100225011	Ron Parker	Shot 11 ran full length.
Feb 25 2010 12:04:39:200PM	1100225012	Ron Parker	Shot 12 ran full length
Feb 25 2010 12:05:08:230PM	1100225013	Ron Parker	Shot 13 ran full length
Feb 25 2010 12:19:10:370PM	1100225014	Ron Parker	Shot 14 went off as programmed, full length.
Feb 25 2010 12:34:23:107PM	1100225015	Ron Parker	Shot 15 ran full length. I would say that the shots continue to roll, but I don't want to jinx it.
Feb 25 2010 12:38:28:237PM	1100225015	Ron Parker	Next: Programmed nel_04 will be set at 1.0e20 m-2.
Feb 25 2010 12:52:13:533PM	1100225016	Ron Parker	Shot 16 ran full length
Feb 25 2010 01:03:32:110PM	1100225017	Ron Parker	Shot 17 ran full length. Next: Raise target density to 1.2e20 m-2.
Feb 25 2010 01:17:17:643PM	1100225018	Ron Parker	Shot 18 ran full length, but density didn't make it to 1.2e20 m-2. Next:set programmed density to 1.3e20 m-2.
Feb 25 2010 01:37:25:430PM	1100225019	Ron Parker	Shot 19 ran full length, but density programming ramped down before H-mode transition. We'll extend density programming to 1.4 s.
Feb 25 2010 01:52:09:667PM	1100225020	Ron Parker	Shot 20 ran full length. Next: no change for PO
Feb 25 2010 02:02:02:660PM	1100225021	Ron Parker	Shot 21 ran full length. Next: Set programmed density to 1.4e20 m-2
Feb 25 2010 02:07:34:417PM	1100225022	Ron Parker	Another full length shot.
Feb 25 2010 02:13:26:580PM	1100225022	Ron Parker	So now it's NINJA's turn to feed the tokamak. Programmed nel_04=0.4e20 m-2
Feb 25 2010 02:33:21:133PM	1100225023	Ron Parker	Shot 23 ran full length. No change form PO for next shot
Feb 25 2010 02:37:14:267PM	1100225024	Ron Parker	Shot 24 ran well, but RF wasn't ready. Repeat for next shot, waiting for RF to be ready.
Feb 25 2010 02:59:16:990PM	1100225025	Ron Parker	Shot 25 ran full length. No PO changes for next shot.
Feb 25 2010 03:07:35:330PM	1100225026	Ron Parker	Same story, full length shot.
Feb 25 2010 03:27:27:650PM	1100225027	Ron Parker	Failure in EF1 Upper circuit. Commutated early. No plasma. We'll run the shot again.
Feb 25 2010 03:31:14:310PM	1100225028	Ron Parker	OK, the shot is back.
Feb 25 2010 03:49:09:580PM	1100225029	Ron Parker	Shot 29 ran, and ran full length. Next: increase programmed nel_04 to 6e19 m-2.
Feb 25 2010 04:04:31:410PM	1100225030	Ron Parker	Shot 30 ran full length Next: Increase i_p to 1.1 MA
Feb 25 2010 04:15:29:360PM	1100225031	Ron Parker	Shot 31 ran full length, low RF power. Next: Igor is asked for more power.
Feb 25 2010 04:27:54:763PM	1100225032	Ron Parker	Shot 32 ran full length.
Mar 10 2010 04:43:00:263PM	1100225033	Ron Parker	Ran full length at 1.1 MA
Mar 10 2010 04:44:06:607PM	1100225034	Ron Parker	Went for 1.2 MA, but plasma disrupted as q passed through 3

Engineering Operator Comments
Shot	Time	Type	Status	Comment
1	09:06:24:760AM	Plasma	Ok
2	09:23:38:747AM	Plasma	Ok
3	09:37:38:390AM	Plasma	Ok
4	09:51:48:827AM	Plasma	Ok
5	10:05:00:200AM	Plasma	Ok
6	10:18:04:983AM	Plasma	Ok
7	10:32:19:013AM	Plasma	Ok
8	10:49:18:377AM	Plasma	Ok
9	11:02:47:643AM	Plasma	Ok
10	11:19:53:303AM	Plasma	Ok
11	11:33:34:523AM	Plasma	Ok
12	11:47:08:367AM	Plasma	Ok
13	12:00:16:897PM	Plasma	Ok
14	12:14:50:553PM	Plasma	Ok
15	12:29:31:290PM	Plasma	Ok
16	12:43:14:917PM	Plasma	Ok
17	12:56:31:087PM	Plasma	Ok
18	01:09:55:040PM	Plasma	Ok
19	01:23:20:460PM	Plasma	Ok
20	01:36:34:570PM	Plasma	Ok
21	01:51:44:713PM	Plasma	Ok
22	02:05:17:430PM	Plasma	Ok
23	02:19:23:353PM	Plasma	Ok
24	02:33:32:347PM	Plasma	Ok
25	02:47:22:423PM	Plasma	Ok
26	03:01:18:087PM	Plasma	Ok
27	03:15:13:743PM	Plasma	Bad	EF1L commutation problem
28	03:28:51:713PM	Plasma	Ok
29	03:42:02:743PM	Plasma	Ok
30	03:55:10:447PM	Plasma	Ok
31	04:08:53:367PM	Plasma	Ok
32	04:23:06:557PM	Plasma	Ok
33	04:37:57:760PM	Plasma	Ok
34	04:51:09:137PM	Plasma	Ok