| Miniproposals | ||||||||||
|
| Operators | |
| Session leader(s): | Amanda Hubbard |
| Physics operator(s): | Robert Granetz |
| Engineering operator(s): | Andy Pfeiffer,Bill Byford |
| Engineering Operator Run Comment |
| MP 490: LHCD into L and H-modes (focus on the H-mode). Session Leader: A |
| Session Leader Plans |
| Entered: Mar 5 2008 07:30:14:300PM |
| Author: Amanda Hubbard |
| Run plan for Thursday, March 6, 2008
MP 490: LHCD into L and H-modes (focus on the H-mode). Session Leader: Amanda Hubbard Physics Operator: Bob Granetz. Requesting overnight boronization. Expect to use cryopump on nearly every shot. Aim: Establish whether, and under what conditions, measurable LHCD can be obtained in H-mode plasmas on C-Mod. Since we expect the changes to be modest, do this in steady, flat top, conditions to see them more clearly. 1) Develop steady, low density H-mode at 600 kA, 5.4 T. Start from 1080125021, tweaking Ssep/Zcur programming. Form H-mode slightly lower null, go to slightly upper null (to give Ssep~+4 mm) in H-mode. Use ~2.5 MW ICRF, mostly J, some E-port. (3-4 shots?) LHCD can use these shots to tune and condition for part of the flat top at moderate power. 2) Apply LHCD at 90 degrees, after H-mode is formed, also turn off during H-mode. Raise power progressively to max available (1.1 MW?) Monitor Vloop, Li, sawteeth, look for reproducible signatures at LH turn on and turnoff. (4 shots) Following sequence will depend on what response is seen under these conditions. Option A: If we DO see evident current drive, try 3) Decreasing phasing (75 degrees?) to minimum nominally accessible value. Try to find limit for which CD is found, so we can compare with the expectations (which do not take proper account of upshifts and downshifts in the plasma). 4) At 90 degrees (or slightly higher), raise Ip (700 kA, 800 kA), see how high we can go and maintain CD. This will be important for future hybrid scenario experiments which would like to run at lower q95~4. Option B: If we do NOT see Vloop changes in step 1: 3) Repeat with LH at 110 degrees. (higher N//) 4) Raise Bt to 6.0 T to ease accessibility. Do CD signatures appear, or get stronger? 5) Reduce Ip to 450 kA. This should reduce both the height and gradient of the H-mode pedestal, either of which could improve H-mode accessibility and coupling. Various combinations of the above will be tried depending on results and available time. Other useful comparisons, if there is time: - Turn cryopump OFF on one or two shots at each current, to document the difference in density. -Especially if results are negative, would be to good run L-modes at the same average density as one of the H-modes. Is the problem density-specific, or related to the steep pedestal? |
| Physics Operators Plans |
| Entered: Mar 5 2008 01:57:47:600PM |
| Author: Robert Granetz |
Engineering setup for Thursday 06 Mar 2008
MP490 LH into H-modes
Session leader: Hubbard
Physics operator: Granetz
** Overnight boronization required **
------------------------------
Boronization Parameters
------------------------------
rmin/rdwell/rmax: 60/75/80 cm
tdwell/tsweep: 60/120 s
~60 mTorr foreline pressure
EF4 current: 200 A
Post boronization ECDC in He, then D2
------------------------------
ECDC Parameters
------------------------------
gas and pressure: D2 at 2e-4 Torr
sweep: 44/45/103 cm
scan: 20/120 s
Vessel temperature: 35/35/35
Run will start at 09:00 and end at 17:00.
Power systems as on 1080125021 (0.6 MA, 5.4 T, 0.6e20 m-2, LSN--> DN--> USN)
A-coil configuration: +Dtop -Dbot -Jtop +Jbot; Enabled (standard
configuration)
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)
leave NINJA as is DISABLED
Enable the following gate valves and shutters, assuming no vacuum problems:
ECE, VUV, Z-bolo
Torvac setup: keep gate valves open
Specific diagnostics: edge TS
-------------------------------------------------------------------------------
ICRF Setup: Need 2.5 MW from E and J, starting with shot 1. Antennas will
need post-boronization conditioning prior to the run.
LH Setup: yes, starting early in run.
DNB: no
Cryopump: yes, starting with shot 1
-------------------------------------------------------------------------------
Run plan: Main goal is to demonstrate measurable current drive with LHCD
into an H-mode plasma.
1) Develop steady low-density H-mode at 0.6 MA, 5.4 T, 2.5 MW mostly from
J, some from E
2) Apply LHCD w/90 deg phasing after H-mode forms. Raise power
shot-to-shot to max available. Look for LH-driven current. Vary
x-point configuration shot-to-shot?
3) If no, repeat with LH phasing set to 110 deg
4) Raise Bt to 6.0 T; try LHCD again.
5) Reduce Ip to 450 kA; repeat. Possibly do the same low current at 5.4 T
|
| Session Leader Summaries |
| Entered: Mar 10 2008 09:17:34:603AM |
| Author: Amanda Hubbard |
| Run summary for Thursday, March 6, 2008
MP 490: LHCD into L and H-modes (focus on the H-mode). Session Leader: Amanda Hubbard Physics Operator: Bob Granetz. Boronized overnight. Use cryopump on most shots. Aim: Establish whether, and under what conditions, measurable LHCD can be obtained in H-mode plasmas on C-Mod. Since we expect the changes to be modest, do this in steady, flat top, conditions to see them more clearly. Results: This was generally a very positive run, and clearly established the first-order objective: Demonstrating a clear and positive effect of LHCD into H-mode plasmas. This is a first for C-Mod, since in our previous attempt last summer LH power was too low, and H-mode densities too high, to see such an effect. In particular, an unexpected benefit was a clear reduction in pedestal and core density, and increase in temperatures, when LHCD was on. Most of the time, and clearest results, were spent on steps 1 and 2 of the proposal, with plasmas at 600 kA, and 5.4 T and 90 degrees LH phasing. The low density H-mode 'recipe' from 1080125 - starting LSN and shifting to Ssep +5 mm early in the H-mode, worked as expected and found previously. nel pumped out to typically 10^20 m-2 following the Ssep step, more quickly as the shots progressed and post-boronization outgassing decreased. ICRF conditioned up over the course of the first six shots. Unfortunately, E-port had a tube problem after shot 7 so we continued with J only, at 1.6-2 MW, for the remainder of the run (D was not requested due to its proximity to the LH launcher). On shots 8-15, LH power was progressively raised from 0.7 MW to about 1 MW. On each of these pulses the following signatures were reproducibly seen, increasing in with power: - reduction in core density (to nel typically 0.85e20 m-2). - reduction in pedestal density. - reduction in radiated power - increase in temperature, both in pedestal and across core. - increase in stored energy - reduction in Vloop (eg 0.88 to 0.58 on shot 13). - reduction in li(typically 1.3 to 1.2. Steve W says this change may be underestimated by EFIT) - increase in hard X-ray emissivity (analysis ongoing, complicated by ICRF effects which also increase x-ray counts). - modest (few 100 eV) increase in non-thermal ECE channels. Core channels appear thermal judging by good agreement with Thompson. - Core rotation shifting from its usual co-current direction in H-mode, becoming more counter-current (reaching negative values in higher power shots 13,14) Maxiumum power coupled was a little over 1 MW, though the highest power shots (14, 15) had a few trips; it is clear that the above changes reverse when LH is off. Shot 13 had PLH ~ 0.9 MW without trips, allowing the plasma response to get to steady state. Careful analysis will be required to determine how much of the Vloop and li response was due to the density and temperature changes and how much to current drive. Either way, the waves are clearly penetrating the H-mode pedestal - which was an open issue - and being deposited in the core plasma, to good effect. After about shot 15, machine conditions began to deteriorate. This may have been related to a small machine leak which apparently opened up starting about shot 13, to problems with cryopump operation, and/or to degradation of the boronization. We may never know. A sympton was that radiated power increased throughout the H-mode, such that in some shots (eg 16) it ended before LHCD turned on. H-mode densities were also somewhat higher (nel~1.1e20 m-2), and the LHCD effects weaker. We did do some variation of LH phase (Step A3 of plan), with 80 degrees (shot 22) and 100 degrees (shot 23). LH effects were much lower in both cases. However, given the above issues, and the cryopump being off at that point, the results were not conclusive and this should be repeated. In particular, 80 degrees was probably inaccessible. It was noted that in several cases a second H-mode transition occurred during, and partly triggered by, the LH pulse (note we were USN by then). These had lower final densities. In some cases very low, transient, Vloop values were seen soon after the L-H transition(eg 0.2 V on shot 25). One discharge at higher Ip (Step A4) (700 kA, shot 26) had quite radiative H-modes and was also not a good test. For the last few shots of the run (26-30), we returned to 600 kA and 90 degrees, and made high density L-modes (by turning on ICRF after the switch to USN), for comparison with the H-modes. Shots 28 had nel ~0.85e20, shot 30 about 0.95 e30, roughly equal to earlier H-modes. LHCD had much more difficulty coupling in these shots due to higher density at the grill, and tripped often. However, it was clear that we did NOT see any of the beneficial effects above. In particular nel if anything rose during LH. So we are probably seeing a pedestal -related effect, whose mechanism is unclear if very welcome. Follow-up experiments, ideally with MSE available, will certainly be valuable to understand and exploit these results. Thanks to all, especially LH operators, who participated. |
| Physics Operator Summaries |
| Entered: Mar 6 2008 05:08:55:253PM |
| Author: Robert Granetz |
Run summary for Thursday 06 Mar 2008
MP490 LH into H-modes
Session leader: A. Hubbard
Physics operator: R. Granetz
The first half of the run was much more productive than the second half.
We used 1.7-2.0 MW of ICRF to obtain H-modes in lower null, then switched
the plasmas to upper null midway through each shot. 0.7-1.0 MW of lower
hybrid then fired into the upper null H-mode plasmas, and clearly dropped
the loop voltage by 0.2-0.3 volts, as well as decreasing ne, raising Te,
and even improving the ICRF coupling a small bit. However, this good
performance eventually degraded throughout the afternoon. See the session
leader's report for more details.
Early in the run we lost the FPA for the E-port ICRF antenna, but we
managed to get enough power from J-port alone to continue with the run.
The tokamak ran very well today, with the only problem being an increase in
N2 and argon around midday, possibly due to a leak in the cryopump system.
Scorecard: 28 plasmas
1 dud (cryopump burped)
2 fizzles
0 power supply tests
0 no-power MDS shot cycles
--------------
Total: 31 shot cycles
|
| Session Leader Comments | |||
| Mar 6 2008 09:11:48:800AM | 1080306001 | Amanda Hubbard | Got the target shot we wanted, complete with Ssep step from -5 mm to +5 mm at 0.7 secs (thanks, Bob). 600 kA, 5.4 T, nel~7e19 m-2, dropping a bit.
Not unexpectedly after last night's boronization, got little ICRF, or LHCD, so stayed in L-mode. Repeat until ICRF conditions up. |
| Mar 6 2008 09:28:26:017AM | 1080306002 | Amanda Hubbard | A bit better, got some power from J and E, and a brief H-mode. Repeat. |
| Mar 6 2008 09:45:45:550AM | 1080306003 | Amanda Hubbard | RF improving (up to 3 MW E+J), but still tripping. Short H-mode again. We don't get it back because we are USN later in the flat top.
Repeat. |
| Mar 6 2008 10:10:47:017AM | 1080306004 | Amanda Hubbard | Finally got a nice long H-mode, with nel dropping to 1.0 m-3 as desired.
But, ICRF still tripping (esp J). Turned off ICRF at 1.2 s this time, to see low LH behaved without it. It did much better. Cell access to pull back LH grill, however, given the glowing probe seen on shot 3 which looks hot even to my untrained eye. |
| Mar 6 2008 10:39:38:737AM | 1080306005 | Amanda Hubbard | Very similar. Long H-mode, but ratty ICRF after 0.8 secs.
ne still pumping out. Next shot, lower J by 0.5 MW, and extend to 1.5 secs to overlap LH pulse again. |
| Mar 6 2008 10:58:26:360AM | 1080306006 | Amanda Hubbard | This shot had overlapped ICRF and LH again - some trips on each. Note Prad rising after about 1.2 secs.
Next: Move LHCD earlier, 1.1-1.4 secs, to see effect more clearly. |
| Mar 6 2008 11:19:46:860AM | 1080306007 | Amanda Hubbard | Good shot - consider this the first of 'step 2'. ICRF stays on with only a few trips, H-mode is nice and steady with nel ~10^20 m-2. LHCD clean 1.1-1.4 secs, at 0.6 MW
Unforturnately, do NOT see any sign of non-thermals or Vloop change. More power igor! Also note a Prad rise towards the end of LH pulse, keep an eye on this as we raise power. Bad news: After shot, it was found we have 'lost' E-port for the rest of the day. Continue with J-only. |
| Mar 6 2008 11:37:37:767AM | 1080306008 | Amanda Hubbard | Nice one. Steady H-mode with 1.6 MW (J only).
When LHCD (0.7 MW) turns on, Vloop drops, ~ 0.82-0.63 V! Note that average density also, unexpectedly, pumps out, 0.97-0.84 e20 m-2, so we will need to assess carefully. Raise LH more next shot. |
| Mar 6 2008 11:43:06:050AM | 1080306009 | Amanda Hubbard | LH 850 kW. Similar effects, but stronger! Vloop 1.1-0.6 V. Ne still pumps out. WMHD increases, and starting to get some ECE increases.
Onward and upwards. |
| Mar 6 2008 11:57:46:470AM | 1080306010 | Amanda Hubbard | 950 kW LH, with some trips. Again, clear Vloop drop, also density pumpout.
Note li is also dropping slightly, 1.3 to 1.2. W 48-53 kJ. All ECE channels rising. The 'non-thermal' edge channels also rise, though weakly (~0.2 keV). Looks like we have both heating and current drive! |
| Mar 6 2008 12:28:45:313PM | 1080306011 | Amanda Hubbard | Good. 930 kW LH, 2 trips. Clear response of both Vloop (0.76 to 0.61 V) and li (1.3 to 1.22) again. |
| Mar 6 2008 12:25:50:957PM | 1080306012 | Amanda Hubbard | 930 kW, only one trip. Similar response - Vloop and li drop.
Jerry says we are getting clear effects of LH on the pedestal. Next: increase right gap a bit. |
| Mar 6 2008 12:46:59:127PM | 1080306013 | Amanda Hubbard | Nice clean LH pulse, 950 kW. Density clearly dropping, also Prad.
Vloop 0.88-0.58 V. Li 1.3 to 1.2. Good viewgraph shot. |
| Mar 6 2008 01:03:34:033PM | 1080306013 | Amanda Hubbard | J-port got nice clean 2 MW. But LHCD trips earlier. Retry. |
| Mar 6 2008 02:28:09:377PM | 1080306014 | Amanda Hubbard |
1.6 MW J. LH 1 MW, trips about 1.3 secs. Nice clear Vloop, density signatures, and heating. |
| Mar 6 2008 02:24:33:580PM | 1080306015 | Amanda Hubbard |
2 MW J-port, LH trips fairly early. 1 MW. Clear pumpout effect, Vloop drop etc. |
| Mar 6 2008 01:20:55:423PM | 1080306016 | Amanda Hubbard | For reasons which are not obvious, had H-L transition just before LHCD came on.
Clean 2 MW J, so that's not it. LH still trips. Next shot, put LH on earlier, at 1.0 s, and back off a little on power. |
| Mar 6 2008 01:29:58:753PM | 1080306017 | Amanda Hubbard | Good. LH on at 1.0 secs, 920 kW. Stays in H-mode, ne pumps out a bit. LH effects are there, but may be weaker. |
| Mar 6 2008 02:00:01:097PM | 1080306018 | Amanda Hubbard | This is rather different in that we lose the first H-mode before the LH comes on.
Density does not decrease as on prior shots, indirect indications are that the cryopump may not be as effective as on prior shots. (IGT did not get as low). Either that or there is a machine leak... LH does stay on OK into the L-mode, and through transition into the second H-mode. Looks like it pumps better than the cryopump... |
| Mar 7 2008 11:45:55:847AM | 1080306019 | Amanda Hubbard | Fizzle. |
| Mar 6 2008 02:42:48:690PM | 1080306020 | Amanda Hubbard | Cryopump OFF. Nominal repeat. Got nice long H-mode, with nel 1.1 e20 (not dropping) before LHCD, pumps to 1.0e20 in LHCD. Good, but higher ne than earlier in the day. And LH signatures weaker.
Next: reduce target ne. |
| Mar 6 2008 02:53:16:813PM | 1080306021 | Amanda Hubbard | CRYO OFF. Nominal target lower (5e19 m-2) actual 5.9 pre RF, 7.3e19 pre L-H transition. H-mode nel 1.1 e20 m-3, not much different.
We lose the first H-mode, just before LHCD pulse@1 sec. Get a second H-mode at 1.14 secs, then lost J-port at 1.28 secs. There is concern we may have a machine (or cryopump) leak. and that something bad happened on J-port. Stay tuned. |
| Mar 6 2008 03:16:08:237PM | 1080306022 | Amanda Hubbard | Cryo OFF. Target nel back up, gave a longer H-mode again.
LH 80 degrees, Gave ne pumpout, but not much Vloop drop.Also, LH trips 1.1 secs, H-mode ends shortly after. Not much headroom at this density it seems. Next shot 100 degrees. |
| Mar 6 2008 03:25:34:877PM | 1080306023 | Amanda Hubbard | Cryo OFF LH 100 degrees.
Big injection cause H-L transition around 1.05 s, plasma never recovered. Many LH trips. repeat, hopefully with cryopump on and without the injection. |
| Mar 6 2008 03:44:34:910PM | 1080306024 | Amanda Hubbard | CRYO ON (but not much change in ne). 100 degrees. First H-mode ends before LHCD, LH clean in second one. Vloop change underwhelming, and no ECE. |
| Mar 6 2008 03:58:17:550PM | 1080306025 | Amanda Hubbard | Back 10 90 degrees. Turn on ICRF later, to get H-mode in USN phase.
Did get H-mode soon after LH, though ne and Prad are rising. H-L around 1.4 secs, same time as LH off, so hard to see Vloop effect. But, Greg notes that early in LH , before full H-mode evolution, Vloop is 0.2 V! nel in H-mode 9.2-9.7e20 m-2, lower than in earlier H-modes (as hoped). But not much headroom. Next shot: 700 kA. Turn LH off earlier. |
| Mar 6 2008 04:10:39:517PM | 1080306026 | Amanda Hubbard | 700 kA. But get three rather transient, radiative H-modes, not v useful.
|
| Mar 7 2008 11:48:09:080AM | 1080306027 | Amanda Hubbard | Try for 600 kA L-mode. USN earlier. Target nel 8e19.
J-port was OK, LH tripped at lot. Did get L-mode A short H-mode late in the day. Already it can be seen that in contrast to the H-modes, nel rises during LH, and Vloop does not drop (may even rise). |
| Mar 6 2008 04:38:15:580PM | 1080306028 | Amanda Hubbard | Programmed density was higher, actual was still around 8.5e19 m-3.
LH still tripping, Might be a transient Vloop drop early this time. Certainly not an ne pumpout. |
| Mar 7 2008 11:50:27:770AM | 1080306029 | Amanda Hubbard | Fizzle |
| Mar 7 2008 11:46:54:457AM | 1080306030 | Amanda Hubbard | Got higher ne L-mode, nel 9.5e19, good comparison to many H-modes.
LHCD was still unhappy at 800 kW. There was NOT any evident pumpout or CD, in fact enl rose slightly at each LH pulse, as did Vloop. |
| Mar 7 2008 11:46:26:503AM | 1080306031 | Amanda Hubbard | 5pm fizzle. End of run. |
| Physics Operator Comments | |||
| Mar 6 2008 08:54:03:450AM | Robert Granetz | Loaded shot 1080125021. Then loaded seg 1 from 1080305001. Set pre-fill pulse to 50 ms since we'll have the cryopump on the first shot. Changed ZCUR programming to remove intermediate step. Plasma should now start LSN and transition to USN starting at t=0.7 s, which will be during the H-mode if the ICRF runs. | |
| Mar 6 2008 09:10:05:730AM | 1080306001 | Robert Granetz | Shot 01 -- Plasma. Good shot. 0.6 MA, 5.4 T, 0.7e20 m-2. No E-port power; J faulted continuously. No H-modes. Configuration changes from LSN to USN between t=0.750 and 0.800 s. Next shot: repeat for better RF. Reduce pre-fill by 3 ms. |
| Mar 6 2008 09:29:14:940AM | 1080306002 | Robert Granetz | Shot 02 -- Plasma. Good shot. ICRF coupling is a little better. Got some power from E-port. LH is faulting continously. Next shot: add 1 ms to pre-fill pulse. ICRF and LH still need to improve their coupling. |
| Mar 6 2008 09:47:05:517AM | 1080306003 | Robert Granetz | Shot 03 -- Plasma. Good shot. ICRF coupling is still not good enough to give robust H-modes. Next shot: add 1 more ms to pre-fill pulse. Repeat for RF conditioning. |
| Mar 6 2008 10:12:26:207AM | 1080306004 | Robert Granetz | Shot 04 -- Plasma. Good shot. E-port is now working pretty well. ICRF purposely turned off at t=1.2 s, so that LH could run without ICRF. LH ran well. Got an H-mode. Cell access granted after this shot to move LH grill back. Next shot: no DPCS changes |
| Mar 6 2008 10:33:58:423AM | 1080306005 | Robert Granetz | Shot 05 -- Plasma. Good shot. Long steady EDA H-mode. E-port is doing well; J is still not there yet. P_LH=0.5-0.6 MW, with no faults, but not simultaneous with ICRF. Next shot: lower requested J-port power to 1.5 MW (from 2.0 MW); no DPCS changes |
| Mar 6 2008 10:57:10:550AM | 1080306006 | Robert Granetz | Shot 06 -- Plasma. Good shot. We now have the ICRF staying on until t=1.5 s. Some faulting. LH goes from t=1.2 to 1.5 s, i.e. simultaneous with ICRF. Looks like there are some interaction issues. Next shot: increase pre-fill by 2 ms. Tweak CLEARIN to keep it and the outer gap more constant from t=1.0 to 1.5 s (requested by LH group). |
| Mar 6 2008 11:10:41:767AM | 1080306007 | Robert Granetz | Shot 07 -- Plasma. Good shot. Much better ICRF and LH performance. LH into H-mode. No drop in loop voltage...actually might be an increase in loop voltage. Outer gap is much steadier late in the flattop. Best startup of the day. Power room access for ICRF after this shot. Next shot: no DPCS changes; increase LH power |
| Mar 6 2008 11:18:59:707AM | 1080306007 | Robert Granetz | A problem occurred with the E-antenna FPA. It's gone for the day. We'll see if J-port alone can provide enough power for H-modes. We might be able to get by with 2 MW. |
| Mar 6 2008 11:31:33:377AM | 1080306008 | Robert Granetz | Shot 08 -- Plasma. Good shot. J-port gave 1.6 MW, but this was enough to get a long H-mode. Good LH pulse; 700 kW. Loop voltage clearly dropped with the LH pulse. ""A distinctly hopeful sign"" says the session leader. Next shot: no DPCS changes. Increase LH power. |
| Mar 6 2008 11:46:55:720AM | 1080306009 | Robert Granetz | Shot 09 -- Plasma. Good shot. Very good ICRF and LH performance. Prf=1.6 MW. P_LH=0.8 MW. LH causes a loop voltage drop, a density pumpout, an increase in Te, and even a slight improvement in ICRF coupling. What more could we ask for? Next shot: no DPCS changes. More LH power. |
| Mar 6 2008 12:00:00:410PM | 1080306010 | Robert Granetz | Shot 10 -- Plasma. Good shot. Good ICRF. LH faulted a bit...shows up clearly on the loop voltage, ne, Te. P_LH=0.93 MW. Next shot: no DPCS changes. |
| Mar 6 2008 12:12:18:110PM | 1080306011 | Robert Granetz | Shot 11 -- Plasma. Good shot. Good ICRF. LH faulted a bit again, perhaps due to outer gap varying a bit. H-mode; loop voltage drop. Next shot: tweak RCUR in to keep outer gap more constant late in flattop. |
| Mar 6 2008 12:22:13:330PM | 1080306012 | Robert Granetz | Shot 12 -- Plasma. Good shot. Good ICRF, good LH. H-mode. Similar effects as previous shots today. Next shot: move RCUR in by 2 mm for the entire flattop in order to increase outer gap by 4 mm (to 14 mm). Also turn on argon (100 ms puff) |
| Mar 6 2008 12:38:51:410PM | 1080306013 | Robert Granetz | Shot 13 -- Plasma. Good shot. Very clean ICRF (1.6-1.7 MW) and LH (0.90-0.95 MW). Outer gap increased to 1.4 cm, as progrmamed. Loop voltage drops by at least 0.3 volts. Even H/(H+D) drops during LH. Next shot: increase pre-fill by 1 ms. |
| Mar 6 2008 12:48:42:003PM | 1080306014 | Robert Granetz | Shot 14 -- Plasma. Good shot. Good ICRF. P_LH=1.0-1.1 MW. H-mode. Loop voltage drop, Te rise, ne drop, Wth rise, H/D drop. Next shot: decrease RCUR by 1.5 mm to increase outer gap by 3 mm; add 1 ms to pre-fill. |
| Mar 6 2008 01:00:32:970PM | 1080306015 | Robert Granetz | Shot 15 -- Plasma. Good shot. Outer gap increased by 2 mm (to 16 mm). LH had some faulting problems. J-port ICRF increased to 2.0 MW. H-mode. Next shot: increase pre-fill pulse another 2 ms. |
| Mar 6 2008 01:21:37:050PM | 1080306016 | Robert Granetz | Shot 16 -- Plasma. Good shot. LH causes bizarre loss of H-mode? Good ICRF. Next shot: add 3 more ms to pre-fill. Move LH pulse earlier. |
| Mar 6 2008 01:37:15:597PM | 1080306017 | Robert Granetz | Shot 17 -- Plasma. Good shot. Good ICRF (2.0 MW). P_LH=0.9 MW. LH comes on at t=1.0 s, which is earlier than previous shots. The drop in loop voltage is still apparent...perhaps not as much as previous shots. Other effects on Te, ne also seem reduced. Next shot: add 1 ms to pre-fill. Reload RCUR from shot 14 (to reduce outer gap by 2 mm). |
| Mar 6 2008 01:55:43:190PM | 1080306019 | Robert Granetz | Shot 18 -- Plasma. Good shot. We lose the H-mode for some reason (before LH turns on). Prf=1.7 MW; P_LH=0.9 MW. Outer gap is back to 14 mm, and the LH seems to do better after the H-mode returns. Suspicion is that the cryopump is not pumping as well, leading to a slightly higher H-mode density. Next shot: repeat, no changes. Don't recool cryopump after the next shot. |
| Mar 6 2008 02:00:27:673PM | 1080306019 | Robert Granetz | Shot 19 -- Fizzle. Next shot: Don't recool cryopump. Therefore decrease pre-fill to 28 ms (from 59 ms). |
| Mar 6 2008 02:21:43:580PM | 1080306019 | Robert Granetz | We're having a delay while we investigate a possible leak. |
| Mar 6 2008 02:40:19:140PM | 1080306020 | Robert Granetz | Shot 20 -- Plasma. Good shot. Cryopump was off for this shot. Long H-mode. Prf=1.7 MW. P_LH=0.9 MW. Nice startup. Next shot: lower target nl_04 to 5e19 m-2 (from 6e19 m-2) |
| Mar 6 2008 02:59:38:707PM | 1080306021 | Robert Granetz | Shot 21 -- Plasma. Good shot. Back to two H-modes. Don't know what's causing the H-L transition just before the LH turns on. Power room access for the ICRF. May have damaged another tube (J4). Next shot: raise nl_04 back to 6e19 m-2. Lower LH phasing to 80 deg. |
| Mar 6 2008 03:14:11:753PM | 1080306022 | Robert Granetz | Shot 22 -- Plasma. Good shot. LH freq is 80 deg. One longish H-mode. Lots of LH faulting. Next shot: change LH phase to 100 deg. |
| Mar 6 2008 03:28:13:330PM | 1080306023 | Robert Granetz | Shot 23 -- Plasma. Good shot. LH phasing is 100 deg. Lots of faulting. H-mode ends early. Next shot: cryopump will be on. Increase pre-fill to 59 ms to compensate. |
| Mar 6 2008 03:40:32:423PM | 1080306024 | Robert Granetz | Shot 24 -- Plasma. Good shot. Two H-modes. Cryopump was on. Next shot: set LH phase back to 90 deg. Cryopump on. |
| Mar 6 2008 03:50:43:753PM | 1080306025 | Robert Granetz | Shot 25 -- Plasma. Good shot. Got ICRF and LH, and an H-mode. Next shot: raise Ip to 0.7 MA |
| Mar 6 2008 04:08:05:220PM | 1080306026 | Robert Granetz | Shot 26 -- Plasma. Good shot. Ip=0.7 MA. Several H-modes, which makes it difficult to discern the effect of the LH. Next shot: change Ip back to 0.6 MA; move ZCUR transition between LSN to USN earlier by 0.2 s; raise nl_04 to 0.8e20 m-2. |
| Mar 6 2008 04:24:08:330PM | 1080306027 | Robert Granetz | Shot 27 -- Plasma. Good shot. Back to 0.6 MA. L-mode until end of flattop, as desired. LH faulted alot. Next shot: raise nl_04 to 0.9e20 m-2; reduce RCUR by 3.5 mm to increase outer gap by 7 mm. |
| Mar 6 2008 04:35:46:877PM | 1080306028 | Robert Granetz | Shot 28 -- Plasma. Good shot. L-Mode. LH had lots of faulting. Next shot: increase nl_04 to 1.0e20 m-2; extend nl_04 to t=1.4 s (was 1.3 s). |
| Mar 6 2008 04:40:57:283PM | 1080306029 | Robert Granetz | Shot 29 -- Dud. Cryopump burped. Pre-fill pressure was 0.15 mTorr. Next shot: try again |
| Mar 6 2008 04:57:45:627PM | 1080306030 | Robert Granetz | Shot 30 -- Plasma. Good shot. L-mode. nl_04=1.0e20 m-2. Some strange spikes on the D-alpha. LH faulted alot. ICRF still running well (J-port). Next shot: no DPCS changes. This will be the last shot. |
| Mar 6 2008 05:06:30:440PM | 1080306031 | Robert Granetz | Shot 31 -- Fizzle. No obvious why. End of run. |
| Engineering Operator Comments | ||||
| Shot | Time | Type | Status | Comment |
| 1 | 09:01:44:040AM | Plasma | Ok | |
| 2 | 09:22:56:753AM | Plasma | Ok | |
| 3 | 09:40:10:517AM | Plasma | Ok | |
| 4 | 09:56:22:237AM | Plasma | Ok | |
| 5 | 10:26:38:313AM | Plasma | Ok | |
| 6 | 10:41:58:127AM | Plasma | Ok | |
| 7 | 10:58:05:220AM | Plasma | Ok | |
| 8 | 11:21:59:737AM | Plasma | Ok | |
| 9 | 11:34:46:910AM | Plasma | Ok | |
| 10 | 11:47:28:160AM | Plasma | Ok | |
| 11 | 12:00:13:003PM | Plasma | Ok | |
| 12 | 12:12:41:987PM | Plasma | Ok | |
| 13 | 12:26:57:550PM | Plasma | Ok | |
| 14 | 12:40:16:720PM | Plasma | Ok | |
| 15 | 12:54:33:860PM | Plasma | Ok | |
| 16 | 01:09:22:830PM | Plasma | Ok | |
| 17 | 01:22:48:017PM | Plasma | Ok | |
| 18 | 01:38:02:080PM | Plasma | Ok | |
| 19 | 01:55:18:660PM | Plasma | Ok | |
| 20 | 02:26:51:563PM | Plasma | Ok | |
| 21 | 02:40:31:877PM | Plasma | Ok | |
| 22 | 03:01:41:063PM | Plasma | Ok | |
| 23 | 03:14:29:267PM | Plasma | Ok | |
| 24 | 03:30:24:753PM | Plasma | Ok | |
| 25 | 03:43:09:610PM | Plasma | Ok | |
| 26 | 03:56:09:860PM | Plasma | Ok | |
| 27 | 04:11:51:847PM | Plasma | Ok | |
| 28 | 04:24:53:377PM | Plasma | Ok | |
| 29 | 04:37:45:207PM | Plasma | Ok | |
| 30 | 04:50:12:173PM | Plasma | Ok | |
| 31 | 05:02:46:190PM | Plasma | Ok | |
| System Availability | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Mar 6 2008 09:01:35:157AM | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Mar 6 2008 09:22:51:627AM | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||