Alcator C-Mod Run 1060614 Information

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Miniproposals
Miniproposal:356
Date Filed:11/12/2003
Title:Mode Conversion Current Drive Experiments
First Author:Alexandre Parisot
Session Leader:Alexandre Parisot (shots 1-18)
Miniproposal:447
Date Filed: 4/4/2006
Title:MCCD experiments during current ramp-up
First Author:Alexandre Parisot
Session Leader:Alexandre Parisot (shots 19-31)

Operators
Session leader(s):Alexandre Parisot,Alexandre Parisot
Physics operator(s):Ian Hutchinson
Engineering operator(s):Bill Parkin

Engineering Operator Run Comment
MP#356 Mode conversioncurrent drive experiments MP#447 MCCD experiments

Session Leader Plans
Entered: Jun 13 2006 05:32:26:763PM
Author: Alexandre Parisot
Session leader plan for 1060614

MP#356 Mode conversion current drive experiments
Session leader: Parisot
Physics operator: Hutchinson

## Note: This plan is contingent upon the status of FRCECE. If it is not working, we'll switch to MP#458 ELM studies (SL: Terry)

The primary goal of this run is to measure net current drive from mode converted waves using loop voltage differences between co/counter phasing. This is a continuation of 1050729 and 1050804.

Run Plan:

0] Run gas tests to check the status of the B-side upper valve.

1] Load 1050804037 (USN, 600 kA, nl04 ~ 0.7), change BT to 5.45 T, 3He puff 100 ms @ 0.2 sec
With J-port flat 0.7-1.4sec in heating phase, and notches for break-in-slope analysis:
Ajust 3He puff for HFS near-axis deposition by changing the 3He puff time and duration
Obtain good MCEH scenario (max power from J-port) and scan density to maximize Te0/(ne0 * Zeff)
Superimpose D and E power up to antenna limits or H-mode threshold. ~ 10 shots

2] Once good target is establish, scan phasing (co, counter, heating), and vary 3He puff to change
the deposition location. Monitor loop voltage changes. ~ 10 shots

Once we are happy with the loop voltage results (or the lack thereof), switch to:

MP#447 MCCD experiments during ramp-up [part 1 - scenario development]
The primary goal of this part is to establish a good mode conversion scenario during the ramp-up phase of the discharge (as early as 150 ms).

Run Plan:
1] Load 1050429015 (the disruption is optional).
J-port on from 0.12s - 0.5s, in heating phase, with notches.
Puff 3He during segment 1 immediately after breakdown (we accidentally did this in 1060613015 and 016).
Monitor 3He concentration and its evolution from HeII line intensity and break-in-slope measurements.
Vary puff in segment II to change and control the MCEH deposition location (goal is near axis on the HFS).
This should take ~ 10 shots.

If time (and luck) allows:
2] Add power from D and E-port and attempt to obtain Alfven cascade activity.

----------------------------------------------------------------------------------------------
Tentative Engineering setup (See PO plan for official version):

Boronization (copied from 1060601):
10% B2D6 / 90% He 6L bottle.
vessel temperature at 60/60/60.
120 psi to be deposited.
PEI setting to 44/70/80 (Rmin/Rres/Rmax) with no pulser.
20 s/60 s sweep time
Gas Pressures: TC3/TC6/TC9/TC6Request = [4 to 7]/150/95/150

Helium ECDC at 5e-5 Torr to be started after the boronization.
Run until 7am, then turn off if requested for work in the cell.
No multipactor or vacuum conditionning is planned.

PEI setting to 44/70/80 during Helium ECDC

A-coil configuration: normal [+Dtop -Dbot -Jtop +Jbot] and enabled.

Power systems as on 1050804037.

Gas Setup:
fill B-Top with 6 psi D2 Hybrid enabled (PG4)
fill B-side lower with 1 psi Ar + 2 psi Ne Hybrid DISABLED (PG1)
fill B-side upper with 15 psi 3He Hybrid enabled
fill B-main (C-side) with 40 psi D2 Hybrid enabled (PG3)
fill NINJA with 12 psi D2 Enabled

Enable the following gate valves and shutters, assuming no vacuum problems:
ECE, VUV, Z-bolo shutters

Important Diagnostics: ECE (FRC-ECE and GPC), HeII monitor, PCI

ICRF Setup: FMIT#1,2,3,4 in run-on by 8:30.

Physics Operators Plans

Session Leader Summaries
Entered: Jun 14 2006 05:25:20:177PM
Author: Alexandre Parisot
MP#356: Mode conversion current drive.
After some struggle and heroic efforts by Josh (who deserves many thanks for this) to fix the FRC-ECE,
we rapidly obtained good target plasmas for MCEH with central heating, low nl04 (~.6) and Zeff (~2.5).
Conditioning J-port after boronization was slow but we obtained good pulses with ~ 2 MW. However, significant
pickup on the magnetics prevented for moving further with this experiment, since it makes the loop voltage
signals suspicious and we would be looking for small differences.

This pickup from J-port on the magnetics is very strange. The pickup is observed on the toroidal field trace, flux loops and b-dot probes. It does not affect diagnostics which usually get problems with 50 MHz leakage in the cell. Also, unlike previous pickup problems, it depends on the plasma parameters we are running. We ran shot 39 from 1060613 (LSN, 5.2 T, 1 MA) and the pickup was reduced by an order of magnitude. With the same shape, we ran 5.4 T and 0.6 MA, and the pickup on the magnetics was back. More analysis is required to determine the cause of this pick-up and salvage this experiment.

MP#417: MCCD experiments during ramp-up
Obtaining MCEH during ramp-up by puffing 3He in segment 1 was in fact quite easy. The plasmas were pretty reliable, and we did not have problems with MARFEs. We did an extensive scan of the puff duration, which will be useful in determine optimum conditions for next Wednesday's experiment. There is a good deal of density production associated with RF, and with both D and 3He puffs early, the obtained densities are probably too large to observe Alfven cascade activity. We coupled 2 MW of power from D and E without difficulty in these plasmas. Unfortunately, we were not successful at coupling power from J-port in these plasmas. The antenna struggles at powers above ~ 1 MW.

Despite two long cell/power room accesses to fix FRC-ECE and OH fuses, we had 31 shots with pretty good machine operation. We made progress in obtaining good targets for both miniproposals, but could not get to the physics part of either of them. We will have to see what we can do on the pickup and J-port problems before we can proceed.

Physics Operator Summaries
Entered: Jun 14 2006 05:12:17:483PM
Author: Ian Hutchinson
Today we pursued the upper null plasmas desired for He3 current drive expts.

Unfortunately the RF pickup at 50MHz is too severe, even on the
magnetic flux loops, to allow detection of small loop voltage changes,
so the physics was not really accomplished. Nevertheless, we found out
a few things.

1. The disruptions in the configuration studied here that occurred at
about .3s are due to vertical instability. It was fixed by
adjustments to rcur.

2. The RF pickup increases with Bt and decreases with Ip. [Why would
RF pickup measure the safety factor?]

3. Immediate post boronization startup is not too difficult these
days. The field ramp in standard configuration is slightly too
slow, leading to mild bounces and runaways.

4. The Br offset required has changed noticeably compared with the
standard.

Scorecard:
  Shot,Duration(s),Ipmax(MA),Result  Shot,Duration(s),Ipmax,Result
  |   01   1.986   0.686   Plasma  |   02   1.978   0.719   Plasma  |
  |   03   1.977   0.677   Plasma  |   04   1.980   0.692   Plasma  |
  |   05   0.352   0.721   Plasma  |   06   0.323   0.670   Plasma  |
  |   07   1.985   0.708   Plasma  |   08   1.981   0.724   Plasma  |
  |   09   1.983   0.712   Plasma  |   10   0.401   0.629   Plasma  |
  |   11   1.984   0.687   Plasma  |   12   1.982   0.710   Plasma  |
  |   13   1.981   1.018   Plasma  |   14   1.977   1.005   Plasma  |
  |   15   1.924   0.703   Plasma  |   16   0.000   0.049   Fizzle  |
  |   17   1.982   0.719   Plasma  |   18   0.000   0.049   Fizzle  |
  |   19   0.000   0.046   Fizzle  |   20   1.378   0.820   Plasma  |
  |   21   0.000   0.029   Dud     |   22   1.387   0.811   Plasma  |
  |   23   1.393   0.814   Plasma  |   24   0.000   0.035   Dud     |
  |   25   1.396   0.814   Plasma  |   26   1.387   0.812   Plasma  |
  |   27   1.387   0.811   Plasma  |   28   1.388   0.812   Plasma  |
  |   29   1.387   0.837   Plasma  |   30   1.388   0.843   Plasma  |
  |   31   1.390   0.847   Plasma 
Date 1060614:  31 shots.  26 plasmas.   3 fizzles.   2 duds.   0 System Error.
        (Plasma = Ip gt 50.0 kA   Dud = H_alpha lt  0.40 V)
Total plasma duration: 40.66 s (exceeding  -68 kA)

Session Leader Comments
Jun 14 2006 09:45:17:090AM1060614001Alexandre ParisotGood shot. Not sure we injected 3He.
Josh is working on the FRC-ECE, we'll have a (hopefully) short delay due to that.

Next: Increase puff duration to 200ms.
Jun 14 2006 09:48:46:310AM1060614002Alexandre ParisotGood shot. This time we had 3He.
Some electron heating on GPC channels 1,2.

Next: Repeat.
Jun 14 2006 10:26:41:170AM1060614003Alexandre ParisotGood shot. J will need some serious conditionning.
Josh reports FRC-ECE should be working now.
There seems to be a lot of pickup from J-port on various traces, including the loop voltage.

Next: Reduce puff time to 150 ms.
Jun 14 2006 10:41:16:843AM1060614004Alexandre ParisotWe now have FRC-ECE data, however there seems to be an offset in the time base.
Less pickup on the loop voltage and other traces (why ?).

Next: Reduce puff time to 120 ms.
Jun 14 2006 10:44:46:597AM1060614005Alexandre ParisotEarly disruption.
Jun 14 2006 11:01:36:260AM1060614006Alexandre ParisotEarly disruption.
Jun 14 2006 11:23:30:250AM1060614007Alexandre ParisotGood shot. Concentration estimate from FRC-ECE: 7 %.
J-port is slowly getting there.

Next: Increase 3He puff duration to 200ms (Target is ~ 15% 3He)
Jun 14 2006 11:36:28:413AM1060614008Alexandre ParisotGood shot. Pick-up is back on the loop voltage.

Next: 3He puff duration to 175ms
Jun 14 2006 11:49:07:057AM1060614009Alexandre ParisotGood shot. Concentration estimate is ~ 15 %, this is what we want.
So we're left with two things:
- condition up J-port
- see what we can do about the pickup.

Next: Repeat.



Jun 14 2006 11:57:40:110AM1060614010Alexandre ParisotRunaway plasma.
(Luckily) disrupted early.



Jun 14 2006 12:13:12:520PM1060614011Alexandre ParisotGood shot. Central heating still seen on the ECE.

Next: Raise power from J-port.




Jun 14 2006 12:39:14:123PM1060614013Alexandre ParisotPlasma full length. H-modes (LSN!)
J-port ran, no or very little pickup on magnetics.

Next: Raise Bt to 5.45 T.



Jun 14 2006 12:48:28:317PM1060614014Alexandre ParisotPlasma full length. Pickup is worse.

Next: Change Ip to 600 kA.



Jun 14 2006 12:58:56:383PM1060614015Alexandre ParisotPlasma full length. J faulted out

Next: Retune.



Jun 14 2006 01:09:18:040PM1060614016Alexandre ParisotFizzle.



Jun 14 2006 01:28:05:977PM1060614017Alexandre ParisotPlasma. Pickup is worse with lower current (higher q95).

Next: Switch to MP#447.
Load 1050429015. Extend flatop to 1.0 sec
J-port on from 0.15-0.5sec, D&E 0.5-0.8sec, LH will fire after 0.8sec






Jun 14 2006 01:36:06:073PM1060614018Alexandre ParisotFizzle.
Jun 14 2006 01:50:01:250PM1060614019Alexandre ParisotFizzle.
Jun 14 2006 02:11:27:993PM1060614020Alexandre ParisotPlasma. Everything looks fine during ramp-up.

Next: Puff 3He 0-100 ms
Jun 14 2006 02:16:38:183PM1060614021Alexandre Parisotdud
Jun 14 2006 03:12:07:983PM1060614022Alexandre ParisotPlasma. Full length.
No problem getting 3He in the plasma during segment 1. The electron temperature responds to J-port.

Next: Reduce puff duration to 50 ms (0-50ms)
Jun 14 2006 03:23:10:253PM1060614023Alexandre ParisotPlasma. Full length.
The electron heating is less efficient. Still difficult to obtain a concentration estimate.

Next: Reduce puff duration to 75 ms (0-75ms)
Jun 14 2006 03:57:09:033PM1060614025Alexandre ParisotPlasma. Full length.
The electron heating is less efficient than shot 22.

Next: Increase puff duration to 150 ms (0-150ms). Co-current drive.
Jun 14 2006 04:08:09:977PM1060614026Alexandre ParisotPlasma. Full length. Very good electron heating at the end of the RF pulse.

Next: Go the opposite phasing.
Jun 14 2006 04:30:06:670PM1060614027Alexandre ParisotPlasma. J mismatched.

Next: Retune.
Jun 14 2006 04:30:40:967PM1060614028Alexandre ParisotPlasma. Still many faults on J.

Next: Add power from D and E 1 MW each.
Jun 14 2006 04:42:44:427PM1060614029Alexandre ParisotPlasma. D and E ran OK. Still many faults on J.

Next: Reduce puff duration to 125 ms. Go to opposite phasing.
Jun 14 2006 05:10:35:797PM1060614030Alexandre ParisotPlasma. D and E ran OK. Still many faults on J.

Next: Repeat. Lower J-port power to 1 MW.
Jun 14 2006 05:11:09:483PM1060614031Alexandre ParisotPlasma. D and E ran OK. J is better, but I doubt we'll get anything will only 1 MW.

Next: End of run.

Physics Operator Comments
Jun 14 2006 08:35:59:377AMIan HutchinsonExamined the two shots under consideration. Found their active segments.

Load from 1060613035, yesterday.

Load seg 3 from 1050804037 seg 3. 0.6MA Upper null. Lots of messages.
Called all predictors, wires 1-8.
Load/clean. Seems to work.

Load seg 4 from 10050429015 seg 4. 0.8 MA Upper null.
Called all predictors, wires 1-8.
Load/clean. Seems to work.

Ok now we have what ought to be viable shots in all segments. 3 and 4 are the
segments we have called for today.

Turn off seg 2. Turn on seg 3. I notice that the segments 3 and 4 seem to have
the reference set to IP for 9-12, which is probably right for their settings.
However, in the modern shot the reference is 10. The active channel is 9,
which is what we are using for the B21_proj feedback. This presumably needs to
be added to the old shots. So set their refs to 10 (seg3 and 4).

Load wire 9 segs 3 and 4 from wire 9 seg 2.

Seg 3: That shot has TF -158416A and gets 5.69T. We want 5.45T so
151.7 kA (Use 152kA). Set TF to 152kA.
Set PG2 (supposedly Bside upper1, He3) to 100ms.

No seg 4 adjustments (yet). Load.

Jun 14 2006 09:34:59:477AM1060614001Ian HutchinsonPlasma. All seems to work well (except RF).
The He3 monitor (parisot/scopes/gas.dat) indicates only very small puff.
Some RF pickup problems and maybe some physics associated with RF trips on
and off.

Cell access to figure out the FRECE problem.
Gas puff PG2 to 200ms.
Jun 14 2006 10:12:21:130AM1060614002Ian HutchinsonPlasma. He3 appears but takes almost 70ms before it starts to come in.

Cell entry to fix various things
No PCS changes.
Jun 14 2006 10:31:30:793AM1060614003Ian HutchinsonPlasma. He3 seems enough to raise nl04 a bit.
RF pickup is really bad.

He3 puff to 150ms.
Jun 14 2006 10:42:13:237AM1060614004Ian HutchinsonPlasma. RF pickup not as bad.

He3 puff to 120ms.
Jun 14 2006 11:02:01:383AM1060614005Ian HutchinsonPlasma disrupts at .35s
Jun 14 2006 11:13:54:467AM1060614006Ian HutchinsonPlasma. Very similar disruption.
On close examination, this is a vertical stability problem, present incipiently in all these shots at about this time.

Move rcur out to .656 at .25s to lower the elongation at this critical time.
Jun 14 2006 11:34:40:570AM1060614007Ian HutchinsonPlasma. Survived, but there's still some instability in that time range so
we need a bit more of that.

Rcur to .658 at .25s
He3 puff back to 200ms.
Jun 14 2006 11:45:34:603AM1060614008Ian HutchinsonPlasma. Vertical problem practically fixed. Can't really push any more on rcur.

He3 puff to 175ms.
Jun 14 2006 11:53:47:920AM1060614009Ian HutchinsonPlasma. Pickup very bad.

Lower nl04 demand to .4e20 to turn off D2 puff.
Tweak rcur at .35s.
Jun 14 2006 12:20:13:603PM1060614010Ian HutchinsonPlasma disrupts early. This was almost all runaways. Startup problem.

Br offset to -.001 from -.0007
Jun 14 2006 12:20:19:807PM1060614011Ian HutchinsonPlasma.
Jun 14 2006 12:33:23:373PM1060614012Ian HutchinsonPlasma.

Since pickup is bad we reload shot 39 from yesterday to prove it is not a difference in the plasma.

Jun 14 2006 12:48:24:690PM1060614013Ian HutchinsonPlasma. The pickup is far less for this shot. So we proved the opposite.

Raise Bt to 152kA to see if field difference is the cause of the pickup difference.

Also Br offset to -.001T in seg 1.
Jun 14 2006 12:57:21:320PM1060614014Ian HutchinsonPlasma. Pickup noticeably worse. Visible on TF.

Lower Ip to 600kA.
Jun 14 2006 01:09:23:430PM1060614015Ian HutchinsonPlasma. No significant RF.
Jun 14 2006 01:13:33:237PM1060614016Ian HutchinsonFizzle. Not obvious why.
Jun 14 2006 01:35:37:713PM1060614017Ian HutchinsonPlasma.Pickup is worse still. Back to practically where it was for the upper-null shot.


Load from shot 12 today.
Extend segment 4 Ip flattop to 1s.
Turn off seg3; turn on segment 4.
Jun 14 2006 01:49:36:983PM1060614018Ian HutchinsonFizzle.

Lower fill puff to 18ms. A sacrifice to the GasHead Gods.
ICEF4 to -1330 from -1335. More likely to do something.
Jun 14 2006 02:02:21:897PM1060614019Ian HutchinsonFizzle.

Br offset to -.0013T
Puff to 21ms.
Jun 14 2006 02:18:37:353PM1060614020Ian HutchinsonPlasma. Bt ramped down early. This is not what is wanted.

Lengthen Bt by loading from segment2 and adjusting. This includes the back porch.
Remove PG2 puff from seg 4. Put 150ms in seg 1 starting at t=0.
Jun 14 2006 03:03:16:683PM1060614021Ian HutchinsonDud. Power supplies breakers pulled before 0.

Hiatus for fixing OH2.
Jun 14 2006 03:17:36:877PM1060614022Ian HutchinsonPlasma. Got plenty of He3 and pickup.

Reduce PG2 puff duration to 0-49ms.
Jun 14 2006 03:26:36:240PM1060614023Ian HutchinsonPlasma. Got about half the He3 monitor signal. Works fine.

There's a funny effect where the TF ramps back up again as if it is reverting to one of the other segments.

Paste TF trace in segment 4 from segment 1 to try to fix
Jun 14 2006 03:37:23:370PM1060614024Ian HutchinsonNo TF.
Jun 14 2006 03:57:08:347PM1060614025Ian HutchinsonPlasma.

Br offset to -.001

PG2 to 100ms in segment 1 plus .1-.15s in segment 2. 150ms total.
Jun 14 2006 04:40:17:753PM1060614029Ian HutchinsonPlasma.

EF3 voltage to 2600V at 12ms.
Jun 14 2006 04:45:34:300PM1060614029Ian HutchinsonPlasma. Perhaps slightly better startup. D and E port RF.

EF3 voltage to 2700 at 12ms.
Jun 14 2006 04:56:01:477PM1060614030Ian HutchinsonPlasma. No improvement in startup.

EF3 back to 2500. EF4 to -1325A.

Engineering Operator Comments
ShotTimeTypeStatusComment
109:02:29:777AMPlasmaOk
209:34:26:740AMPlasmaOk
310:13:16:833AMPlasmaOk
410:28:00:950AMPlasmaOk
510:42:41:910AMPlasmaOk
611:00:01:710AMPlasmaOk
711:12:29:827AMPlasmaOk
811:25:11:597AMPlasmaOk
911:37:38:913AMPlasmaOk
1011:51:23:683AMPlasmaOk
1112:04:19:860PMPlasmaOk
1212:17:12:350PMPlasmaOk
1312:29:37:230PMPlasmaOk
1412:42:26:250PMPlasmaOk
1512:55:01:583PMPlasmaOk
1601:07:32:260PMPlasmaOk
1701:20:11:110PMPlasmaOk
1801:34:07:947PMPlasmaOk
1901:48:01:657PMPlasmaOk
2002:00:46:647PMPlasmaOk
2102:14:40:540PMPlasmaBad3 blown fuses OH2U
2203:01:28:573PMPlasmaOk
2303:14:18:093PMPlasmaOk
2403:30:00:633PMPlasmaBadNo TF
2503:42:54:420PMPlasmaOk
2603:55:38:283PMPlasmaOk
2704:08:18:333PMPlasmaOk
2804:23:02:903PMPlasmaOk
2904:36:00:237PMPlasmaOk
3004:52:05:587PMPlasmaOk
3105:04:38:683PMPlasmaOk