Alcator C-Mod Run 960206 Information

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Miniproposals
Miniproposal:132
Date Filed:12/20/1995
Title:ICRF H Mode Confinement With Boronized Walls
First Author:Steve Golovato
Session Leader:Yuichi Takase (shots 1-17)

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

Engineering Operator Run Comment
boronized H-mode

Session Leader Plans

Physics Operators Plans

Session Leader Summaries
Entered: Jul 7 2004 03:49:15:100PM
Author: To Be Determined
MP#132 Boronized H-mode (5.3-6T)

SL Takase
PO Wolfe
EO Bertolino/Daigle

Run Plan:
1. start with 960116025 (5.3T, 1.0MA)
extend TF (and everything else) to 1.1sec
sharp RF turn-off @ 1.05sec
2. Program TF ramp 5.3T@0.6s -> 6T@1.0s (may need to adjust programming)
take a few shots (gpc outer channels sweeping through separatrix)
3. TF scan (no ramp) @ 1.0MA
BT H resonance
5.3T R=0.667m
5.6 0.705
5.8 0.730
6.0 0.755
4. Raise Ip to 1.2MA at highest field with good H-mode
take a few shots, raising P_RF
5. PEP H-mode

The run started late because of an air leak (Dan Lo's SMA feedthru -- see
the physics operator's summary for detail).
The fiducial shot (shot 003) did achieve H-mode with 1MW of RF power, but
the quality of H-mode was poor. Jim Terry reports sightings of nitrogen
(even on the last shot of the day), and oxygen on earlier shots.

The run went reasonably well, in spite of the late start.
All of the objectives 1-5 were at least partially achieved.
It was found that slightly off-axis resonance does not degrade the H-mode.
Some variations were observed during the field scan
(field ramps and shot-to-shot scans). There is some evidence
that slightly higher field (5.6-5.7T) may be better than on-axis resonance
(5.3T), but the variation was small (less than 10% on the stored energy).
The H-factor was not as high as the highest we have achieved in the past,
but still respectable (up to about 1.7, for example on shot 011).
Transiently higher values (up to about 2 but declining slowly with time,
for example on shot 016) were also observed.
HIREX had data acquisition problems part way through the run.

Li pellet was injected on shots 014 and 017, but did not produce a nice
PEP mode. Deuterium was puffed into the divertor on shots 014, 015, and
017. Deuterium puffing in the divertor does seem to have an unfavorable
effect on H-mode. See shots 015 (with divertor puff) and 016 (without puff)
for comparison, with otherwise identical conditions.

01 test OH test
02 test TF test (with filter installed)
03 pl fiducial, RF started late, got H-mode
04 pl load 960116025 (5.3T 1.0MA), TF flattop to 1.2s, 136kJ
05 pl TF ramp 5.3T@0.7s->6.0T@0.95s, same W_EFIT
06 pl TF ramp 5.3T@0.65s->6.0T@0.9s->5.4T@1.1s, 153kJ before disrupting
07 pl TF ramp 5.3T@0.65s->5.7T@0.84s->5.3T@1.0s, 160kJ @ 5.7T
08 pl TF ramp 5.3T@0.80s->5.9T@1.05s, 156kJ
09 pl TF ramp 5.3T@0.80s->5.9T@1.05s, 168kJ
10 pl TF @ 5.3T, 160kJ
11 pl TF @ 5.6T, 169kJ
12 pl TF @ 5.8T, 163kJ
13 pl TF @ 6.0T, 166kJ
14 pl TF @ 5.8T, Li pellet @ 0.63s, D2 div puff @ 0.90s, no PEP, 149kJ
15 pl TF @ 5.8T, 1.2MA, no Li pellet, D2 div puff @ 0.85s
16 pl TF @ 5.8T, 1.2MA, no Li pellet, no D2 div puff
17 pl TF @ 5.8T, Li pellet @ 0.64s, D2 div puff @ 0.85s, no PEP, 166kJ


Physics Operator Summaries
Entered: Jul 7 2004 04:36:56:020PM
Author: To Be Determined
Physics Operator Summary for Tuesday, 960206

MP#132 Boronized H-modes
SL Takase
PO wolfe
EO Silva/Bertolino/Daigle

Run plan:
---------
1. start with 960116025 (5.3T, 1.0MA)
extend TF (and everything else) to 1.1sec
sharp RF turn-off @ 1.05sec
2. Program TF ramp 5.3T@0.6s -> 6T@1.0s (may need to adjust programming)
take a few shots (gpc outer channels sweeping through separatrix)
3. TF scan (no ramp) @ 1.0MA
BT H resonance
5.3T R=0.667m
5.6 0.705
5.8 0.730
6.0 0.755
4. Raise Ip to 1.2MA at highest field with good H-mode
take a few shots, raising P_RF
5. PEP H-mode

Overnight boronization was carried out, followed by 90minutes
of He ECDC. However, a 1X10^-6Torr air leak occurred after completion of
boronization. After much searching, the leak was located at a feedthru on the
charged fusion product probe. The leak was temporarily bagged off with a He
purge, and ECDC in D2 was carried out for 90minutes to try to reduce the air
contamination on the walls. After ECDC the DYCOR RGA was showing about 1e-8 on
the 28 peak, as well as significant diborane complex. The run began around
12:30PM

In addtition to the usual Tuesday OH Coax test, we also had a TF test to check
operation of a new filter in the gate drive circuit. This filter (15Hz) was
installed to prevent an oscillation in the alterator at TF inversion from high
field. It seemed that it did slow down the TF response, but did not obviously
improve the oscillation.

SHot 3 was the fiducial, taken from 960201001. It looked ok, although the
h-mode was a little ratty.

Considering the fact that we only got half a run, the main part of the run
went quite well. We accomplished all the five items in the run plan, and got
pretty good H-modes, but no new records.

Shot 4 was based on program from the record shot 960116025, but with waveforms
extended to 1.1sec, and TF under hybrid control. I also reduced the pre-puff to
14msec (from 18). This shot went well but h-factor was not great, getting only
133kJ.

Shots 5-9 had various TF ramps during the RF to get edge profiles from the
GPC. This was successful, and the H-factors did seem to improve as we took
more shots. Shot 9 was up to 167kJ. Shot 9 was also the first shot with RF
feedback on RCUR turned on, with a weight of -1500.

Shots 10-13 were flat TF at different fields (5.3,5.6,5.8,6.0) to test
off-axis heating. These all showed good H-modes and good stored energy. The
h-modes actually seemed to marginally improve, and the radiated power (as seen
on the 2pi) decreased as the field was increased. This could be a real effect
or it could be just evidence of improved wall condition.

Shot 14 was back to 5.8T and featured a Li pellet and a NINJA puff in the
divertor. The PEP h-mode ended up with 150kJ.

Shot 15-17 were at 1.2MA and 5.8T (q~3.4). SHot 15 had NINJA but no pellet,
and got a quite respectable 202kJ at the peak, then W decayed. Shot 16 was a
lower density target (asked for 6e19, got about 7.5e19); got about 200kJ but
the 2pi was around 5MW! Shot 17 had a pellet, and a larger NINJA puff; got
165kJ and a disruption, probably an injection. All these shots had a strike
point that just missed the outer target, i.e. marginally slot configuration.

Other problems, observations
----------------------------
I encountered a zero-divide error in the load database phase of the
PUT_FIDUCIAL routine. Aside from notifying JAS and Terry I did not pursue it.

Hybrid TF control worked well, allowing multiple Bt ramps with good acccuracy.

There were CAMAC problems on DAQ3 highway on a few shots, fixed by Joe Bosco.

There was a problem with the HIREX CAMAC involving flaky memory modules. This
cost data on a number of shots.

There was a long delay before shot 15 when PCS started generating error
messages on LOAD_INTO_MODEL. These came from the P_to_V routines, but were in
fact ultimately diagnosed by Josh as being due to a resource (global page)
problem on PHYSOP which in turn arose because of a gotcha in an "improvement"
he and Tom made to the SCOPE programs, entirely unrelated to PCS, which caused
iconized SCOPES to gobble up pages and not let go. An important lesson from
this, aside from "Call Josh at the first sign of trouble", is that it is
essential that the physop pay attention to the message stream from PCS. Had I
not noticed the error messages I might have tried to run a 1.2MA shot with a
lot of garbage in the downloaded program.

Cooling seemed to work well today, with only one shot having a significant
wait for the C-top arm to cool.

A little D2 ECDC does not seem to adversely affect the fresh boronization, at
least not by much.

We left the TF off the fizzle detector all day (after the fiducial) with the
idea that a fizzle would provide a free diamagnetic baseline for whatever
condition it happened in. This was doubtless the reason we didn't get any
fizzles.

Scorecard:
----------
Shots 17
Tests 2
Plasmas 15
Duds 0
Fizzles 0

Session Leader Comments
Feb 6 1996 01:18:26:480PMYuichi TakaseMP#132 Boronized H-mode (5.3-6T)

SL Takase
PO Wolfe
EO Bertolino/Daigle

Run Plan:
1. start with 960116025 (5.3T, 1.0MA)
extend TF (and everything else) to 1.1sec
sharp RF turn-off @ 1.05sec
2. Program TF ramp 5.3T@0.6s -> 6T@1.0s (may need to adjust programming)
take a few shots (gpc outer channels sweeping through separatrix)
3. TF scan (no ramp) @ 1.0MA
BT H resonance
5.3T R=0.667m
5.6 0.705
5.8 0.730
6.0 0.755
4. Raise Ip to 1.2MA at highest field with good H-mode
take a few shots, raising P_RF
5. PEP H-mode

The run started late because of an air leak (Dan Lo's SMA feedthru -- see
the physics operator's summary for detail).

Feb 6 1996 01:18:59:080PM960206001Yuichi TakaseShot 001: OH test

Feb 6 1996 01:19:57:280PM960206002Yuichi TakaseShot 002: TF test (with filter installed)

Feb 6 1996 06:07:07:330PM960206003Yuichi TakaseShot 003: plasma
fiducial, RF started late, got H-mode

Feb 6 1996 06:07:26:400PM960206004Yuichi TakaseShot 004: plasma
load 960116025 (5.3T 1.0MA), TF flattop to 1.2s, 136kJ

Feb 6 1996 06:07:44:720PM960206005Yuichi TakaseShot 005: plasma
TF ramp 5.3T@0.7s->6.0T@0.95s, same W_EFIT

Feb 6 1996 06:08:06:080PM960206006Yuichi TakaseShot 006: plasma
TF ramp 5.3T@0.65s->6.0T@0.9s->5.4T@1.1s, 153kJ before disrupting

Feb 6 1996 06:08:22:960PM960206007Yuichi TakaseShot 007: plasma
TF ramp 5.3T@0.65s->5.7T@0.84s->5.3T@1.0s, 160kJ @ 5.7T

Feb 6 1996 06:08:44:690PM960206008Yuichi TakaseShot 008: plasma
TF ramp 5.3T@0.80s->5.9T@1.05s, 156kJ

Feb 6 1996 06:08:59:830PM960206009Yuichi TakaseShot 009: plasma
TF ramp 5.3T@0.80s->5.9T@1.05s, 168kJ

Feb 6 1996 06:09:16:100PM960206010Yuichi TakaseShot 010: plasma
TF @ 5.3T, 160kJ

Feb 6 1996 06:09:29:790PM960206011Yuichi TakaseShot 011: plasma
TF @ 5.6T, 169kJ

Feb 6 1996 06:09:43:420PM960206012Yuichi TakaseShot 012: plasma
TF @ 5.8T, 163kJ

Feb 6 1996 06:09:57:010PM960206013Yuichi TakaseShot 013: plasma
TF @ 6.0T, 166kJ

Feb 6 1996 06:10:10:440PM960206014Yuichi TakaseShot 014: plasma
TF @ 5.8T, Li pellet @ 0.63s, D2 div puff @ 0.90s, no PEP, 149kJ

Feb 6 1996 06:10:25:890PM960206015Yuichi TakaseShot 015: plasma
TF @ 5.8T, 1.2MA, no Li pellet, D2 div puff @ 0.85s

Feb 6 1996 06:10:40:130PM960206016Yuichi TakaseShot 016: plasma
TF @ 5.8T, 1.2MA, no Li pellet, no D2 div puff

Feb 6 1996 06:10:54:440PM960206017Yuichi TakaseShot 017: plasma
TF @ 5.8T, Li pellet @ 0.64s, D2 div puff @ 0.85s, no PEP, 166kJ

Physics Operator Comments
Feb 6 1996 07:24:30:900AMSteve WolfeMP#132 Boronized H-modes
SL Takase
PO Wolfe
EO Silva/?

setup:
Overnight boronization
ECDC in He for 1.5 to 2hrs prior to run

Gas setup:
A-side 20psi D2
B-top 5psi D2
B-side lower 4psi Ar
B-side upper As is (He3 - don't touch)
NINJA Pumped out.

1. Tuesday OH test
2. Fiducial setup from 960201001
3. Begin experiment with setup from 960116025, except:
TF under hybrid control, PLC limit set to 167kA
TF invert at 1.2 sec
Shot same as 960116025 but flattop extended to 1.1sec
PCS shot is stored in USER9:[WOLFE.MDS.SHOTS.HYBRID.PCS]pcs_960206901
4. TF ramp during rf to get edge gpc profile
5. shot-to-shot tf scan
6. 1.2MA at highest field with good H-mode
7. PEP h-mode

Feb 6 1996 07:36:26:390AMSteve WolfeFiducial shot loaded last night from 960201001
coldstart done last night,just in case.
coldstart redone this morning: 6-FEB-1996 07:29:18.61
Checked PCS files - ok
PCS set up for 1MA,1.1sec shot -- DO NOT LOAD until after fiducial.

Feb 6 1996 08:17:18:720AMSteve Wolfe0800 - We had an air leak, apparently enough to shut down ECDC.
The 28 peak got to nearly 1e-6 on the DYCOR!
ECDC actually seems to have gone off because it ran out of gas in the
plenum. The leak may have been there for some time and only appeared
when the ECDC went off (RGA sensitivity is suppresed).

08:15 - Ar etc are dropping some, but 28 is still high and may be
rising.

Feb 6 1996 11:06:18:620AMSteve WolfeLeak found at a feedthrough on Dan Lo's probe at K-port.
Presently bagged and flowing He at 5CFM. ECDC until noon and see how it
goes.

Feb 6 1996 12:38:28:420PM960206001Steve WolfeShot 960201001 - Tuesday coax test: ok

Feb 6 1996 12:54:07:480PM960206002Steve WolfeShot 960201002 - TF test: The filter does seem to have slowed it down,
but it's not clear the alternator ripple was affected.

Feb 6 1996 01:24:57:930PM960206003Steve WolfeShot 960201003 - fiducial: Looks ok, got h-mode. Got some injections
during and before RF. H-mode looks pretty marginal.

Feb 6 1996 01:41:54:960PM960206004Steve WolfeShot 960201004 - Load based on 960116025, except TF under hybrid control,
all waveforms and gains extended to 1.1sec, and pre-pulse to 14msec
(was 18!)

Plasma- ramped down ok. ONly 133kJ though.

Feb 6 1996 01:51:38:070PM960206005Steve WolfeShot 960201005 - Put ramp on TF from .7sec to 1.1sec up to 6.0T (164.1kA)
Plasma - TF ramp took the current to new flattop (164000) by 0.96sec.

Feb 6 1996 02:16:21:750PM960206006Steve WolfeShot 960201006 - Put in a ramp up and down (.65-.9 up, .9-1.1down)
and reduce PG3 seg 2 pulse after .4sec to 0.

DIsrupted at 1sec. LOoks like the radiation goes way up in H-mode.
150kJ before it gets in trouble. 2pi Prad gets to 3MW on the first
h-mode, then has an injection (?) at .9sec during the second.

Feb 6 1996 02:32:04:100PM960206007Steve WolfeShot 960201007 - PUt PG3 gas pulse back
Change TF ramp to go from 5.3 to 5.8T and back
with sweeps at .65 and .82sec

Plasma up and down. 2pi reaches 3MW.

Feb 6 1996 02:48:44:460PM960206008Steve WolfeShot 960201008 - Raise the seg 1 gas puff from 35 to 50 (Ian's suggestion
to get rid of current rise disruption). Move ramp to .8 sec, 6T, no down
ramp before 1.1sec
PLasma- the puff seems to get rid of the mini-disruption at .09.
RF faulted half-way thru. 152kJ but 3000kW on 2pi

Feb 6 1996 03:03:21:850PM960206009Steve WolfeShot 960201009 - RF feedback on RCUR (-1500). No other changes
PLasma - no RF crowbar this time
2pi goes to 2600 and saturates. 167kJ

Feb 6 1996 03:14:01:590PM960206010Steve WolfeShot 960201010 - TF flat at 5.3T
Plasma H-mode looks ok. JR is having memory module problems.
159kJ

Feb 6 1996 03:24:40:460PM960206011Steve WolfeShot 960201011 - TF flat at 5.6T (changed seg1 & seg2)
PLasma - hmode - 2pi at 2.4MW - 168kJ

Feb 6 1996 03:34:01:600PM960206012Steve WolfeShot 960201012 - TF flat at 5.8T (changed seg1 & seg2)
PLasma - hmode, 2pi at 2350, 162kJ

Feb 6 1996 03:52:01:800PM960206013Steve WolfeShot 960201013 - TF flat at 6.0T (changed seg1 & seg2)
PLasma - CAMAC errors on bus rogs
H-mode, 2pi=1.9MW , 164kJ

Feb 6 1996 04:09:13:000PM960206014Steve WolfeShot 960201014 - TF flat at 5.8T (changed seg1 & seg2)
Pellet before RF, NINJA at .7 (should come in at .8sec)
Plasma - pellet, H-mode, 2pi=2.5MW, 150kJ

Feb 6 1996 04:45:43:300PM960206015Steve WolfeShot 960201015 - TF flat at 5.8T
Raise Ip to 1.2MA
NINJA pressure to 12psi (from 8)
PCS bombs out in p-to-V (error -- unknown node name) due to a change
that T&J made to scopes that ate global pages (I have no idea what that
means) Long delay while JAS figures this out and remedies the situation

H-mode through 1sec, then faults. 200kJ

Feb 6 1996 04:57:23:860PM960206016Steve WolfeShot 960201016 - drop program density to 6e19 (from 7, we are getting 9)
plasma - 2pi=5MW, 199kJ

Feb 6 1996 05:23:53:410PM960206017Steve WolfeShot 960201017 - density back to 7e19. Ar puff reduced at JR's request!
NINJA and LPI on again, EF3 current limit to 15kA

Disrupts at 1.15, at 1MA. Got a halo warning.
Fast pump out after pellet. H-mode terminates at about 1sec, possible
injection
Ian points out that the last several shots have been marginal slot
divertors.
Only 165kJ.

Engineering Operator Comments
ShotTimeTypeStatusComment
112:32:12:520PMTestOk
212:40:18:700PMTestOk
301:20:15:390PMPlasmaOk
401:32:11:520PMPlasmaOk
501:47:00:990PMPlasmaOk
602:02:30:270PMPlasmaOk
702:20:45:570PMPlasmaOk
802:37:29:370PMPlasmaOk
902:54:35:330PMPlasmaOk
1003:05:13:190PMPlasmaOk
1103:16:16:830PMPlasmaOk
1203:26:27:520PMPlasmaOk
1303:44:28:040PMPlasmaOk
1404:00:57:830PMPlasmaOk
1504:37:23:310PMPlasmaOk
1604:48:58:830PMPlasmaOk
1704:59:30:790PMPlasmaOk