Alcator C-Mod Run 960213 Information

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Miniproposals
Miniproposal:117
Date Filed: 4/18/1995
Title:3He Minority Heating at 7.9T
First Author:Yuichi Takase
Session Leader:Yuichi Takase (shots 1-19)

Operators
Session leader(s):Yuichi Takase
Physics operator(s):Steve Wolfe
Engineering operator(s):Joe Daigle,Frank Silva,Vinny Bertolino

Engineering Operator Run Comment
8T Wolfe

Session Leader Plans

Physics Operators Plans

Session Leader Summaries
Entered: Jul 7 2004 03:49:15:163PM
Author: To Be Determined
Run summary 960213

MP#117 7.9T D(He3) heating
SL: Takase
PO: Wolfe
EO: Silva/Bertolino/Daigle

Overnight boronization
ECDC in He for 2hrs before run

Run plan:

1. Fiducial
2. 5.3T H-mode conditioning shots
Also try off-axis (outside of sawtooth inversion radius) heating
3. 8T H-mode, 1.0MA then 1.2MA
Try various RF power step programming (including modulation)

Another late start, plus leaks, power glitch, etc. (see the physics
operator's summary for details). We did achieve the record stored
energy at 8T (nearly 200kJ) with a good H-factor (about 1.8).

We took 7 shots at lower fields (5.3T and 6.2T) to condition the
freshly boronized wall for H-mode operation, including one fiducial shot.
As observed during previous weeks, it was clear that H-mode quality
improved over the first several shots, but after 7 shots we have not yet
achieved the "well-conditioned" H-mode performance (960116025).
Shots at 6.2T had the minority resonance outside the sawtooth inversion
radius. Although the central temperature increase was lower, as expected,
the stored energy increase was comparable to on-axis resonance heating.
This is very different from the pre-boronization result.

The problem with the 8T diamagnetic measurement was identified to be
saturated signal. The measurement looks promising after the saturation
problem is fixed (after shot 14). We did obtain good H-modes at 1.2MA.
Shot 18 had RF power modulation, but it stayed in L-mode for most of
the RF pulse. Shot 19 had RF power steps (unintentional) which would
be useful for evaluating the absorption efficiency (preliminary analysis
indicates approximately 60% absorption).

Shot
01 test Relay test
02 test OH test
03 test TF test
04 fiz 5.3T 1MA (loaded 960116025) H-mode conditioning
05 pla disrupt @ 1s, nel=1.1 @ RF turn on, 2.5MW 120kJ
06 dud mag res fault
07 pla 2.5MW, 115kJ, inj @ 0.63s
08 pla 6.2T (res outside q=1) nicer shot, 2.5MW, 135kJ
09 pla 5.3T disruption @ 1.14s, 2.5MW, 150kJ
10 pla 6.2T got nel=0.8, worse H-mode, inj before RF, 2.5MW, 115kJ
11 pla 5.3T fiducial 72kJ @ 1MW
12 pla 6.2T 2.5MW, 145kJ, HeII baseline shot (very little background)

start 8T run
13 pla 7.9T 1.0MA (loaded 960207012) 50ms He3 puff, 2.4MW, 128kJ
cell access for Granetz to fix diamag (saturates @ 8T)
14 pla disr @ 0.1s (Granetz's integrator board out)
15 pla 30ms He3 puff, 1.0MW (D-port only), 90kJ (no H-mode)
N2 leak after shot
16 pla 35ms He3 puff, 2.5MW, 198kJ (delayed H-mode)
17 pla 2.5MW, 193kJ (short H-mode, inj @ 0.9s)
delay caused by leak and power glitch
18 pla RF modulation 1.3-2.5MW, 136kJ (late H-mode)
19 pla good power steps from E-port trips, 2.8MW, 175kJ

Physics Operator Summaries
Entered: Jul 7 2004 04:36:56:100PM
Author: To Be Determined
Phys Op Summary for Tuesday 960213

MP# 117 7.9T D(He3) heating
SL: Takase
PO: wolfe
EO: Silva/Bertolino/Daigle

Run Plan
--------
After boronization, He ECDC

0. OH and TF tests
1. Fiducial
2. 5.3T H-mode conditioning shots
Also try off-axis (outside of sawtooth inversion radius) heating
3. 8T H-mode, 1.0MA then 1.2MA
Try various RF power step programming (including modulation)

The run got off to a late start due to a variety of SNAFUs, the most
serious of which was a bug in the CRYO PLC program which prevented the relays
from closing and the 5V supply from turning on for the resistance
measurements. "Don't upgrade a working system!" Shot #1 was a no-power cycle
to try to get the relays to close. First power test was #2, run at around
10AM.

A TF test (#3)was requested by the engineers because the filter on the TF was
changed again, this time to .75Hz. The test went ok, with a reduction in
alternator oscillations, but Vinnie later decided that the filter wasn't
properly configured and put it back the way it was before.

The fiducial was postponed because there was a problem with the VUV,
eventually traced to a cable interfering with the limit switch on the stepping
motor drive. It was eventually taken at shot #11.

We started with 1MA conditioning discharges, based on 960116025 and 960206004.
Shots #4 fizzled - Br too negative at 0.0064. Changed to .0074 for next shot.
Shots #5,7-10,12 were 1MA conditioning shots, some at 5.3T and some at 6.2T.
Off-axis heating seemed to work as well or better than on-axis. There was a
clear improvement in confinement over this sequence. Shot 6 was a dud with no
13.8 supplies (spurious magnet resistance fault). Shot#11 was the fiducial.

Shot 13-19 were at 7.9T, #15-19 at 1.2MA. See the logbook for shot-by-shot
record. Best shots were probably 16 and 17 which got close to 200kJ.

Shot 14 had no Ip trace or feedback because RSG had removed the integrator
board to prevent saturation of the diamagnetic signal, without realizing the
same board had the rogowski integrator. The shot actually ran until shortly
after segment switch.

There were long delays caused by a N2/Ar leak, later an air leak. This was
probably but not definitely the B-bottom leak, on which the purge had become
semi-operative. At about the same time the alternator house had a power glitch
and the speed had to coast down below 1200 rpm before it could be sped up
again. The leak was apparently "fixed" by the end of the run.

The J-port ratiomatic was dead at the start of the day. Joe Snipes changed
filaments during one of the delays. Calibration is unknown. The RGA is also
dead with a blown filament.

All of the 1.2MA shots had EF2 currents above 5kA at .7-.8sec. I reduced these
somewhat by relaxing the RXU and ZXU demands and forcing the EF4 voltage to
stay maxed out through .5sec using the voltage pre-program. On shot 19 EF4 hit
its current rail at +3500A; this should be increased to the admin. limit of
5000A.

In view of the number of shots required to condition after boronization,
running 8T on Tuesday seems to be a bad idea.

Scorecard:
----------
Shots 19
Tests 3
Duds 1
Fizzles 1
Plasmas 14 (counting #14 on which the current didn't register, but reached
>500ka)

Session Leader Comments
Feb 13 1996 09:09:11:480AMYuichi TakaseMP#117 7.9T D(He3) heating
SL: Takase
PO: Wolfe
EO: Silva/Bertolino/Daigle

Overnight boronization
ECDC in He for 2hrs before run

Run plan:

1. Fiducial
2. 5.3T H-mode conditioning shots
Also try off-axis (outside of sawtooth inversion radius) heating
3. 8T H-mode, 1.0MA then 1.2MA
Try various RF power step programming (including modulation)

Feb 13 1996 09:12:33:010AM960213001Yuichi TakaseShot 001: Relay test

Feb 13 1996 09:12:45:410AM960213002Yuichi TakaseShot 002: OH test

Feb 13 1996 09:24:07:340AM960213003Yuichi TakaseShot 003: TF test

Feb 13 1996 10:15:54:890AM960213004Yuichi TakaseShot 004: fizzle
reload of 960116025 (5.3T 1MA H-mode conditioning)

Feb 13 1996 10:46:33:230AM960213005Yuichi TakaseShot 005: plasma
disrupt @ 1s, 2.5MW 120kJ

Feb 13 1996 10:57:37:830AM960213006Yuichi TakaseShot 006: dud
mag res fault

Feb 13 1996 10:58:40:390AM960213007Yuichi TakaseShot 007: plasma
2.5MW, 115kJ, inj @ 0.63s

Feb 13 1996 11:14:14:620AM960213008Yuichi TakaseShot 008: plasma
6.2T nicer shot, 2.5MW, 135kJ

Feb 13 1996 11:45:43:190AM960213009Yuichi TakaseShot 009: plasma
5.3T disruption @ 1.14s, 2.5MW, 150kJ

Feb 13 1996 11:46:38:360AM960213010Yuichi TakaseShot 010: plasma
6.2T got nel=0.8 (have been trying to get this)
worse H-mode, inj before RF, 2.5MW, 115kJ

Feb 13 1996 11:48:04:620AM960213011Yuichi TakaseShot 011: plasma
5.3T fiducial 72kJ @ 1MW

Feb 13 1996 11:59:57:080AM960213012Yuichi TakaseShot 012: plasma
6.2T 2.5MW, 145kJ, HeII baseline shot (very little background)

Feb 13 1996 12:47:13:660PM960213013Yuichi TakaseShot 013: plasma
7.9T 1.0MA (loaded 960207012) 50ms He3 puff, 2.4MW, 128kJ
cell access for Granetz to fix diamag (saturates @ 8T)

Feb 13 1996 12:54:33:480PM960213014Yuichi TakaseShot 014: plasma
disr @ 0.1s (Granetz's integrator board out)

Feb 13 1996 01:59:21:800PM960213015Yuichi TakaseShot 015: plasma
30ms He3 puff, 1.0MW (D-port only), 90kJ (no H-mode)
N2 leak after shot

Feb 13 1996 02:15:25:940PM960213016Yuichi TakaseShot 016: plasma
35ms He3 puff, 2.5MW, 198kJ (delayed H-mode)

Feb 13 1996 02:17:10:380PM960213017Yuichi TakaseShot 017: plasma
2.5MW, 193kJ (short H-mode, inj @ 0.9s)

Feb 13 1996 05:11:10:900PM960213018Yuichi TakaseShot 018: plasma
RF modulation 1.3-2.5MW, 136kJ (late H-mode)

Feb 13 1996 05:11:32:200PM960213019Yuichi TakaseShot 019: plasma
good power steps from E-port trips, 2.8MW, 175kJ

Physics Operator Comments
Feb 13 1996 07:17:46:200AMSteve WolfeMP#117 7.9T D(He3) ICRF
SL: TAkase
PO: Wolfe
EO: Silva/

Plan-
Start with Tuesday OH test and TF test
Fiducial based on 960206003
Run 5T shots conditioning shots until H-mode looks good; may try
off-axis heating at higher field as we wait. Start from 960116025.
7.9T H-mode, 1.0MA then 1.2MA - start from 960207012

Feb 13 1996 08:00:52:390AMSteve WolfeBoronization lasted aboit 12 hours and consumed 120psi of diborane mix.
He ECDC on at 6:45 and off at 8:00

Feb 13 1996 08:13:15:120AM960213001Steve WolfeShot 960213001 - no power test to get relays to cycle.

Feb 13 1996 09:10:36:820AM960213002Steve WolfeShot 960213002 - Tuesday oh test.

Feb 13 1996 09:18:38:200AM960213003Steve WolfeShot 960213003 - TF test. looks ok, no overshoot. Irby says oscillation
is much reduced.

Feb 13 1996 10:17:02:980AM960213004Steve WolfeShot 960213004 - VUV is screwed up. Start the conditioning sequence.
Load 960116025, with pre-pulse reduced to 14msec.

Relay/s and 5V supply screwed up again. Long delay before shot.
Meanwhile JT has fixed the VUV, but we'll start with the conditioning
discharges anyway.
Fizzle.

Feb 13 1996 10:33:43:810AM960213005Steve WolfeShot 960213005 - Increase Br from .0064 to .0074.
Note- ratiomatic seems to be dead again.

PLasma disrupted at 1sec. Looks like an injection at .94sec. About
110kA of halo current. Only 122kJ in h-mode before disruption.

Feb 13 1996 10:37:36:450AM960213006Steve WolfeShot 960213006 - Reduce PG3 to zero from .38sec
Magnet resistance fault. No shot.

Feb 13 1996 10:50:51:300AM960213007Steve WolfeShot 960213007 - Reduce PG3 to zero from .38sec

Plasma - ramps down this time. Still have a current rise disruption as
noted by Ian on last shot. Still only 120kJ

Feb 13 1996 11:05:47:160AM960213008Steve WolfeShot 960213008 - Load 960206004 (longer shot, otherwise same.)
Change Br to .0074, drop PG3 in segment 2, increase late PG3 in seg 1.
Increase PLC setting for TF to 176kA from 151 - should give 6.2T
Vinnie has put the TF supply filter back the way it was last week. He
believes there is something wrong with what was installed.

Plasma - ramps down ok. Still getting a rising density before RF. 140kJ.

Feb 13 1996 11:18:11:760AM960213009Steve WolfeShot 960213009 - Drop PG3 segmewnt 2 puff a little earlier. Go back to
5.3T

PLasma disrupted at 1.15sec (early ramp down). 150kJ.

Feb 13 1996 11:32:50:680AM960213009Steve WolfeShot 960213010- Back to 176kA (6.2T) on TF.

Plasma- ramps down ok. No halpha blob, multiple stutters in H-mode.
117kJ.

Feb 13 1996 11:32:56:010AM960213010Steve WolfeShot 960213010- Back to 176kA (6.2T) on TF.

Plasma- ramps down ok. No halpha blob, multiple stutters in H-mode.
117kJ.

Feb 13 1996 11:40:17:970AM960213011Steve WolfeShot 960213011- Fiducial, load 960206003 and change Br to .0074.

Fiducial ok.

Feb 13 1996 11:58:47:020AM960213012Steve WolfeShot 960213012- reload from shot 10 and put back some of the seg2
gas puff. Back to 6.2T.
Plasma - ramps down ok. 145kJ

Feb 13 1996 12:11:40:040PM960213013Steve WolfeShot 960213013- Ready for 8Tesla.
Load from 960207012. Increase He3 puff from 30msec to 50msec.

Plasma - 128kJ. RF not on all the time.

Feb 13 1996 12:45:08:880PM960213014Steve WolfeShot 960213014- Raise current to 1.2MA. GO back to 30msec He3 puff.
Reduce seg2 PG3 puff to zero after .45sec to try to eliminate rise in
NL04 above program.

Early disruption. Granetz had removed an integrator board between shots
to fix a saturation on the diamagnetic signal. It looks like he removed
the Ip integrator as well!!

Feb 13 1996 01:32:14:040PM960213015Steve WolfeShot 960213015- Raise current to 1.2MA. GO back to 30msec He3 puff.
Reduce seg2 PG3 puff to zero after .45sec to try to eliminate rise in
NL04 above program. Try again after RSG puts things back.

Plasma - ramps down ok. Only 1MW, just ditrhers no H-mode.

Feb 13 1996 01:45:42:620PM960213016Steve WolfeShot 960213016- Increase He3 puff to 35msec. There was a N2 leak between
shots; seems to have reclosed.

Plasma- RF ok from .73, doesn't get into H-mode until .86. In between
there is a burst of vertical instability. 200kJ.
Ian points out we are moving very close to the antenna at .45sec.

Feb 13 1996 02:34:40:400PM960213017Steve WolfeShot 960213017- Reduce NL_04 demand to 7e19 (from 8). Move plasma in a
bit before .5sec. Remove RXL zig-zag.

Plasma - still getting very high EF2U currents. This one drops put of
H-mode at .92sec; why? Gets to 193kJ before it drops out.
No spectroscopy data on H-alpa, 2pi, z-meter. CAMAC INIT failure.

Feb 13 1996 02:34:58:300PM960213017Steve WolfeShot 960213017- Reduce NL_04 demand to 7e19 (from 8). Move plasma in a
bit before .5sec. Remove RXL zig-zag.

Plasma - still getting very high EF2U currents. This one drops put of
H-mode at .92sec; why? Gets to 193kJ before it drops out.
No spectroscopy data on H-alpa, 2pi, z-meter. CAMAC INIT failure.

Feb 13 1996 04:17:30:520PM960213018Steve WolfeShot 960213018- Move RXU and ZXU in and down to try to get rid of
large EF2U currents.
Long delay due to leak, then a power glitch which drops the alternator.

Plasma - EF2U is still high, but better. RF power was modulated, probably
a bit too much; It doesn't really get into a good H-mode. 130kJ.

Feb 13 1996 04:47:25:270PM960213019Steve WolfeShot 960213019- Noticed that EF4 demand was actually dropping between
200 an 400ms, possibly lengthening time in crossover. Fix this using
V_EF4 for shot 19.

Plasma - disrupted in rampdown, PF crowbar. Brick. Also there was an RF
dropout. Got to 170kJ before bad things happened. EF4 hit current rail
(3.5kA) at 1sec. EF2U is down a bit, still high.

Engineering Operator Comments
ShotTimeTypeStatusComment
106:28:13:900AMTestOk
209:05:37:120AMTestOkoh test
309:13:54:200AMTestOk
410:11:15:760AMPlasmaOk
510:22:07:610AMPlasmaOk
610:35:58:520AMPlasmaBadmag res fault in pulse
710:43:29:260AMPlasmaOk
810:57:06:350AMPlasmaOk
911:10:23:370AMPlasmaOk
1011:25:08:650AMPlasmaOk
1111:38:05:760AMPlasmaOk
1211:50:54:570AMPlasmaOk
1312:03:53:930PMPlasmaOk
1412:39:08:890PMPlasmaOk
1501:00:14:320PMPlasmaOk
1601:35:26:330PMPlasmaOk
1702:03:13:520PMPlasmaOk
1804:08:49:220PMPlasmaOk
1904:36:55:750PMPlasmaOkComm fault OH2U & OH1