Alcator C-Mod Run 1021008 Information

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Miniproposals
Miniproposal:304
Date Filed: 6/19/2002
Title:H-Mode Regimes
First Author:Martin Greenwald
Session Leader:Martin Greenwald (shots 1-18)

Operators
Session leader(s):Martin Greenwald
Physics operator(s):Bill Rowan
Engineering operator(s):Gary Dekow

Engineering Operator Run Comment
MP#304 H-mode regimes; SL: Greenwald; PO: Rowan; EO: Dekow

Session Leader Plans

Physics Operators Plans

Session Leader Summaries
Entered: Jul 7 2004 03:49:31:130PM
Author: To Be Determined
Run Summary for 1021008
mp 304 H-mode regimes

Session Leader - Greenwald
Phys Op - Rowan

============================

Plan:

Given machine constraints, Emphasis will be on the EDA/ELMfree
boundary as a function of delta. The hope is that the loose tile
will not cause too much trouble. Even this study will be constrained
because of limits on plasma current.

The overall strategy is to pick a triangularity, get an H-mode. If
it is EDA, we scan up in current (down in q) till the discharge goes
ELMfree. If it is ELMfree, we scan down in current till it goes
EDA. Then go to next value of triangularity.

- start at the highest triangularity, maybe delta_av = 0.7, then
scan to 0.55 and 0.35. If time permits (hah!) we'll try to fill in.
a possible shot to start with would be 1020930015, though we
need to increase the upper triangularity.

- Bt = 5.3 or whatever value it is these days that puts the D&E
antennas squarely on the magnetic axis

- no power scans - steady power at about 2 MW

- start at 1 MA for the high triangularity. we can probably drop
the base current as the triangularity is lowered.


==============================

Results:

Not great luck today. Recovery from boronization was quicker than
expected, but 4 hours were lost to a problem eventually traced to a
power cable in the RF tuning system. Afterwards the RF was slow to
come up to power - and a pair of high current disruptions and
subsequent recovery took most of the rest of the afternoon.

For the afternoon we switched to an Ip scan to maximize results
(sacrificing pedestal profile studies).

shot 17 was the only one that could contribute to the mp (though the
RF power dropped to 1 MW at the L/H transition). It had average
triangularity of 0.64 and q scanning from 5.3 to 4.6. A clear QC
mode was seen on PCI, though the radiated power and density ramped
continuously.

================================


Physics Operator Summaries
Entered: Jul 7 2004 04:37:16:473PM
Author: To Be Determined
Physop Summary for Tuesday, October 8th, Run 1021008


Run Plan and Engineering Setup---------------------------------------------

Recovery from Boronization

MP#304 H-mode regimes
Session leader: Greenwald
Physics Operator: Rowan

For the experiment, use segment 2 of 1020930015 and segment 1
of 1021003024

The overall strategy is to pick a triangularity, get an H-mode. If
it is EDA, we scan up in current (down in q) till the discharge goes
ELMfree. If it is ELMfree, we scan down in current till it goes
EDA. Then choose a new value of triangularity.

Overnight boronization.
ECDC in D2 after boronization until 7:00 am

Run begins at 9:00 am and ends at 5:00 pm

Set up for possible ECDC in D2 between shots.

Power systems as on 1020930015

Gas setup:
fill B-Top with 6 psi D2 Hybrid enabled (PG4)
fill B-side lower with 1 psi Ar Hybrid enabled (PG1)
fill B-side upper with 10 psi D2 Hybrid DISABLED (PG2) (for ECDC)
fill C-side with 30 psi D2 Hybrid enabled (PG3)
leave J-Bottom as is Hybrid DISABLED (PG5)

Enable the following gate valves:
ECE, VUV, DNB

-------------------------------------------------------------------------------
RF Setup: FMIT#1 and 2 transmitters in Run On by 08:00
-------------------------------------------------------------------------------


Results-------------------------------------------------------------------------
Boronization Recovery
The plasma started up without difficulty. By shot 006, full length plasma
shots were produced although we did continue to lose shots to boronization
recovery throughout the day. Minor error field corrections and pressure
corrections were made.

Progress on the MP
Shot 017 contains the triangularity, the q-scan, and the RF required for
this MP. The other shots were used for shape setup, lacked RF, or failed
to produce plasmas. One very long delay (after shot 006) was due to a failed
controller for an RF tuning stub. A couple of shots were lost due to engineering
problems.

Logbook Entries-------------------------------------------------------------------

Run Plan and Engineering setup for Tuesday, October 8th, Run 1021008

Recovery from Boronization

MP#304 H-mode regimes
Session leader: Greenwald
Physics Operator: Rowan

For the experiment, use segment 2 of 1020930015 and segment 1
of 1021003024

The overall strategy is to pick a triangularity, get an H-mode. If
it is EDA, we scan up in current (down in q) till the discharge goes
ELMfree. If it is ELMfree, we scan down in current till it goes
EDA. Then choose a new value of triangularity.

Overnight boronization.
ECDC in D2 after boronization until 7:00 am

Run begins at 9:00 am and ends at 5:00 pm

Set up for possible ECDC in D2 between shots.

Power systems as on 1020930015

Gas setup:
fill B-Top with 6 psi D2 Hybrid enabled (PG4)
fill B-side lower with 1 psi Ar Hybrid enabled (PG1)
fill B-side upper with 10 psi D2 Hybrid DISABLED (PG2) (for ECDC)
fill C-side with 30 psi D2 Hybrid enabled (PG3)
leave J-Bottom as is Hybrid DISABLED (PG5)

Enable the following gate valves:
ECE, VUV, DNB

-------------------------------------------------------------------------------
RF Setup: FMIT#1 and 2 transmitters in Run On by 08:00
-------------------------------------------------------------------------------

From Irby: Possible late start due to boronization delays

Engineering Operator did the cold start.

Loaded segment 1 from 1021003024
Loaded segment 2 from 1020930015

30 minutes of ecdc after completion of boronization.

RF did some conditioning after ECDC shut down.

Will do 10 minutes of ECDC before the first shot.

Not requesting RF for the first few shots because this is boronization recovery

Some additional delay before the first shot. Last minute shutter work. RF repair

002. Fizzle
The prefill pressure was too high. Aroound 0.08mT

For the next shot.
Reduced the prefill from 27 ms to 23 ms.


003. Segment 2 was turned off on this shot.


005. Plasma.

Next shot.
Increase BZ by changing IC_EF4 from -1325 to -1315
Add 1 ms to the prefill. It is not 24 ms
Reduced ZXU form 0.03 to 0.027

Long delay before next shot. Waiting for RF repairs.
Problem with control of a stub tuner.

006. Plasma

Next shot.
RXU decreased by approximatly 0.025m
ZXU decreased from 0.027 to 0.020
Current ramping from 0.8 MA to 1.2 MA during the RF

007. Plasma

Next shot.
RXL flattened
RXU corrected to avoid the double null around 0.6s
Ip ramp down started at 1.4s

008. Fizzle.

Not sure what the pressure was. Ratiomatic was off.

Next shot.
Reloaded segment 2 form sho 007.
Added 1 ms to the prefill

009. Fizzle
EF3 breaker pulled before the shot.

Next shot.
RXU corrected to avoid the double null around 0.6s
Ip ramp down started at 1.4s
Modified RXL to flatted DeltaL

010. No shot. Engineering problems.


011. Plasma

Next shot. No changes

012. Plasma disrupted at 1.5 s. On the current ramp down.

Next shot.
Reduced the current peak to 1.1MA

013. Fizzle

Next shot.
Reduced the TF to 5.3 T.

014. Plasma. Disrupted at 1.5 s on the rampddown

Next shot.
Made a small change in RXU so that the demand does not
change so rapidly after 1.4 s


015. Fizzle

Next shot.
Reduced BZ_0; ic_ef4 reduced from -1315 to -1325


016. Dud
Engineering problem.
Blown fuse on OH2L

017. Plasma. No disruption

H-mode from 0.8 s to 1.1 s

Next shot.
Put the current peak back at 1.2 MA

018. Fizzle



Session Leader Comments
Oct 8 2002 09:38:51:820AMMartin GreenwaldBackground:

Previous experiments have explored the EDA/ELMfree boundary and
found strong dependence on q and $\delta$. Other studies have found
a boundary between EDA and type II ELMs at high $\beta$ (or
$\alpha$) and high temperature. In particular we will exploit the
increased shaping and increased RF power available during this
campaign.

Plan:

Given machine constraints, Emphasis will be on the EDA/ELMfree
boundary as a function of delta. The hope is that the loose tile
will not cause too much trouble. Even this study will be constrained
because of limits on plasma current.

The overall strategy is to pick a triangularity, get an H-mode. If
it is EDA, we scan up in current (down in q) till the discharge goes
ELMfree. If it is ELMfree, we scan down in current till it goes
EDA. Then go to next value of triangularity.

- start at the highest triangularity, maybe delta_av = 0.7, then
scan to 0.55 and 0.35. If time permits (hah!) we'll try to fill in.
a possible shot to start with would be 1020625021, though we
probably need to back of slightly on the upper triangularity to
avoid double null.

- Bt = 5.3 or whatever value it is these days that puts the D&E
antennas squarely on the magnetic axis

- no power scans - steady power at about 2 MW

- start at 1 MA for the high triangularity. we can probably drop
the base current as the triangularity is lowered.

Oct 8 2002 05:24:05:007PMMartin Greenwald
Results:

Not great luck today. Recovery from boronization was quicker than
expected, but 4 hours were lost to a problem eventually traced to a
power cable in the RF tuning system. Afterwards the RF was slow to
come up to power - and a pair of high current disruptions and
subsequent recovery took most of the rest of the afternoon.

For the afternoon we switched to an Ip scan to maximize results
(sacrificing pedestal profile studies).


shot 17 was the only one that could contribute to the mp (though the
RF power dropped to 1 MW at the L/H transition). It had average
triangularity of 0.64 and q scanning from 5.3 to 4.6. A clear QC
mode was seen on PCI, though the radiated power and density ramped
continuously.

Oct 8 2002 09:42:02:930AM1021008003Martin GreenwaldPlasma - ohmic
Oct 8 2002 09:51:26:333AM1021008004Martin Greenwaldplasma - ohmic
Oct 8 2002 10:08:53:290AM1021008005Martin GreenwaldPlasma - under control this time
still no RF power
Oct 8 2002 01:57:34:467PM1021008006Martin GreenwaldPlasma - ohmic
after long delay
still no RF, but engineering problem is fixed
Oct 8 2002 02:49:26:697PM1021008007Martin GreenwaldPlasma - ohmic
higher triangularity
scanning current now 0.8 - 1.2 during "RF time"
still no RF
Oct 8 2002 02:48:39:103PM1021008008Martin Greenwaldfizzle

Oct 8 2002 02:48:13:243PM1021008009Martin Greenwalddud
Oct 8 2002 02:56:39:477PM1021008010Martin GreenwaldNo power cycle
Oct 8 2002 03:17:28:887PM1021008011Martin GreenwaldPlasma - late H-mode
RF power ramps to 1.8 MW
H-mode is mostly during ohmic phase following RF
Oct 8 2002 03:33:57:853PM1021008012Martin GreenwaldPlasma - L-mode
RF only at 1 MW
Oct 8 2002 03:53:59:667PM1021008013Martin Greenwaldfizzle
Oct 8 2002 03:58:25:667PM1021008014Martin GreenwaldPlasma - L-mode
disrupts early in rampdown
only 1 MW RF
Oct 8 2002 04:07:31:993PM1021008015Martin Greenwaldfizzle
Oct 8 2002 04:24:12:887PM1021008016Martin Greenwalddud
Oct 8 2002 05:01:10:840PM1021008017Martin GreenwaldPlasma - H-mode
QC mode seen on PCI
RF power briefly at 2 MW then drops back to 1 MW
delta_av = 0.642
delta_u = 0.6
delta_l = 0.68
q95 = 4.7

Physics Operator Comments
Oct 8 2002 08:10:17:297AMBill RowanRun Plan and Engineering setup for Tuesday, October 8th, Run 1021008

Recovery from Boronization

MP#304 H-mode regimes
Session leader: Greenwald
Physics Operator: Rowan

For the experiment, use segment 2 of 1020930015 and segment 1
of 1021003024

The overall strategy is to pick a triangularity, get an H-mode. If
it is EDA, we scan up in current (down in q) till the discharge goes
ELMfree. If it is ELMfree, we scan down in current till it goes
EDA. Then choose a new value of triangularity.

Overnight boronization.
ECDC in D2 after boronization until 7:00 am

Run begins at 9:00 am and ends at 5:00 pm

Set up for possible ECDC in D2 between shots.

Power systems as on 1020930015

Gas setup:
fill B-Top with 6 psi D2 Hybrid enabled (PG4)
fill B-side lower with 1 psi Ar Hybrid enabled (PG1)
fill B-side upper with 10 psi D2 Hybrid DISABLED (PG2) (for ECDC)
fill C-side with 30 psi D2 Hybrid enabled (PG3)
leave J-Bottom as is Hybrid DISABLED (PG5)

Enable the following gate valves:
ECE, VUV, DNB

-------------------------------------------------------------------------------
RF Setup: FMIT#1 and 2 transmitters in Run On by 08:00
-------------------------------------------------------------------------------
Oct 8 2002 08:12:22:550AMBill Rowan


From Irby: Possible late start due to boronization delays.
Oct 8 2002 08:36:41:857AMBill RowanEngineering Operator did the cold start.

Loaded segment 1 from 1021003024
Loaded segment 2 from 1020930015

Oct 8 2002 09:03:18:747AMBill Rowan30 minutes of ecdc after completion of boronization.

RF did some conditioning after ECDC shut down.

Will do 10 minutes of ECDC before the first shot.

Not requesting RF for the first few shots because this is boronization recovery
Oct 8 2002 09:20:23:733AMBill RowanSome additional delay before the first shot. Last minute shutter work. RF repair
Oct 8 2002 09:39:29:617AM1021008002Bill Rowan002. Fizzle
The prefill pressure was too high. Aroound 0.08mT

For the next shot.
Reduced the prefill from 27 ms to 23 ms.
Oct 8 2002 09:38:57:023AM1021008003Bill Rowan003. Segment 2 was turned off on this shot.

Next shot. Turn on segment 2 and try again.
Oct 8 2002 10:05:28:427AM1021008005Bill Rowan005. Plasma.


Oct 8 2002 10:12:05:450AM1021008005Bill Rowan
Next shot.
Increase BZ by changing IC_EF4 from -1325 to -1315
Add 1 ms to the prefill. It is not 24 ms
Oct 8 2002 10:21:02:727AM1021008005Bill RowanFor the next shot: Reduced ZXU form 0.03 to 0.027
Oct 8 2002 10:40:22:530AM1021008005Bill RowanLong delay between shots. Waiting for RF repairs.
Oct 8 2002 01:39:12:650PM1021008005Bill RowanProblem with control of a stub tuner. Now repaired.
Continuing with the run
Oct 8 2002 02:00:17:410PM1021008006Bill RowanNext shot.
RXU decreased by approximatly 0.025m
ZXU decreased from 0.027 to 0.020
Current ramping from 0.8 MA to 1.2 MA during the RF
Oct 8 2002 02:19:35:417PM1021008007Bill Rowan007. Plasma

Next shot.
RXL flattened
RXU corrected to avoid the double null around 0.6s
Ip ramp down started at 1.4s
Oct 8 2002 02:35:06:880PM1021008008Bill Rowan008. Fizzle.

Not sure what the pressure was. Ratiomatic was off.

Next shot.
Reloaded segment 2 form sho 007.
Added 1 ms to the prefill
Oct 8 2002 02:50:23:227PM1021008009Bill Rowan009. Fizzle
EF3 breaker pulled before the shot.

Next shot.
RXU corrected to avoid the double null around 0.6s
Ip ramp down started at 1.4s
Modified RXL to flatted DeltaL
Oct 8 2002 02:54:37:417PM1021008010Bill Rowan010. No shot. Engineering problems.
Oct 8 2002 03:22:49:120PM1021008011Bill Rowan011. Plasma

Next shot. No changes
Oct 8 2002 03:33:02:590PM1021008012Bill Rowan012. Plasma disrupted at 1.5 s. On the current ramp down.

Next shot.
Reduced the current peak to 1.1MA
Oct 8 2002 03:51:29:040PM1021008013Bill Rowan013. Fizzle



Next shot.
Reduced the TF to 5.3 T.
Oct 8 2002 04:03:12:743PM1021008014Bill Rowan014. Plasma. Disrupted at 1.5 s on the rampddown

Next shot.
Made a small change in RXU so that the demand does not
change so rapidly after 1.4 s
Oct 8 2002 04:16:49:120PM1021008015Bill Rowan015. Fizzle

Next shot.
Reduced BZ_0; ic_ef4 reduced from -1315 to -1325
Oct 8 2002 04:23:30:650PM1021008016Bill Rowan016. Dud
Engineering problem.
Oct 8 2002 04:31:47:320PM1021008016Bill RowanEngineering problem.
Blown fuse on OH2L
Oct 8 2002 05:01:03:887PM1021008017Bill Rowan017. Plasma. No disruption

H-mode from 0.8 s to 1.1 s

Next shot.
Put the current peak back at 1.2 MA
Oct 8 2002 05:14:34:740PM1021008018Bill Rowan018, Fizzle

Engineering Operator Comments
ShotTimeTypeStatusComment
108:28:54:083AMTestOkCycle Test
209:21:48:237AMPlasmaOk
309:34:50:893AMPlasmaOk
409:48:00:360AMPlasmaOk
510:01:41:813AMPlasmaOk
601:42:52:130PMPlasmaOk
702:02:06:323PMPlasmaOk
802:21:15:013PMPlasmaOk
902:36:48:010PMPlasmaBadEF3 15KV Circuit Breaker Opened Just prior to the shot
1002:52:02:040PMPlasmaBadNo Power Shot Igor Failure from previous cycle
1103:09:47:353PMPlasmaOk
1203:24:16:883PMPlasmaOk
1303:38:41:273PMPlasmaOk
1403:52:25:620PMPlasmaOk
1504:05:20:853PMPlasmaOk
1604:19:36:993PMPlasmaBadPF breaker pulled during pulse OH2L fault
1704:51:34:230PMPlasmaOk
1805:05:23:127PMPlasmaOk