Alcator C-Mod Run 1031010 Information

Back to runs

Miniproposals
Miniproposal:
Date Filed:
Title:
First Author:
Session Leader: Unknown (shots 1-27)

Operators
Session leader(s): Unknown
Physics operator(s):Robert Granetz,Earl Marmar
Engineering operator(s):Bill Parkin,Gary Dekow,Bill Byford,Bill Cochran

Engineering Operator Run Comment
Plasma startup and conditioning PO: Granetz; EO: Dekow/Cochran/Byford/Pa

Session Leader Plans

Physics Operators Plans

Session Leader Summaries

Physics Operator Summaries
Entered: Jul 7 2004 04:37:19:020PM
Author: Earl Marmar
Physics operator summary for run 1031010 (Friday):

Purpose: Plasma startup and conditioning

Session leader: --
Physics operator: R. Granetz/E. Marmar
Engineers in charge: G. Dekow

Summary: Things were going along pretty well until mid-afternoon. Plasma
startup was very reliable, and most shots lasted well into rampdown.
The H/D ratio was 0.3-0.4. Some RF power was also being injected.
Then, right around the time we decided to try for upper null plasmas
(shot 16), things turned ugly. We had many computer/network problems
which resulted in three lost shot cycles, lots of delays, and
eventually ended the run early. Two of the upper null attempts
successfully produced plasmas, but most were fizzles.

Scorecard: 15 plasmas
7 fizzles
2 duds
0 tests or no-power shot cycles
3 aborted and/or screwed up by computer problems
----------
27 total

-------------------------------------------------------------------------------
Engineering setup for Friday, 10 Oct 2003

Purpose: Plasma startup and conditioning

Session leader: --
Physics operator: R. Granetz (am) /E. Marmar (pm)
Engineering operator:

ECDC overnight in D2 at 2e-4 Torr, stopping by 07:00.
Bake at 60 C overnight as well.

Run begins at 09:00 and ends at 17:00.

Power systems the same as on 1031009018 (1.0 MA, 5.4 T, lower single null)

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)

Enable the following gate valves, assuming no vacuum problems:
ECE, VUV, DNB

-------------------------------------------------------------------------------
RF Setup: Transmitters 1,2,3, and 4 in RUN ON by 08:00 am

-------------------------------------------------------------------------------
Run Plan: Once we get reliable startup, we'll continue running boring cleanup
plasmas while monitoring H/D, etc. RF Group may start conditioning.

-------------------------------------------------------------------------------

ECDC was done overnight, as well as a 60 C bake.

Hybrid coldstart done by the engineering group; no errors found

Loaded PCS from shot 1031009019 (1.0 MA, 5.4 T, nl_04=1.0e20 m-2,
single null lower), and reduced Ip to 0.8 MA.

-------------------------------------------------------------------------------

Shot 01 -- Plasma. Disrupted at t=0.50 s after becoming resistive. Startup
looked good, even though Bz is higher than last campaign.

Next shot: reduce pre-fill by 3 ms.

Shot 02 -- Plasma. Another short, resistive shot. Disrupted at t=0.48 s.

Next shot: reduce Ip to 0.6 MA, reduce nl_04 to 0.6e20 m-2, and
reduce gas valve voltage preprogramming.

Shot 03 -- Dud. Problem with OH2U commutation.

Next shot: repeat, no changes.

Shot 04 -- Plasma. Lasted until t=0.69 s, but even at Ip=0.6 MA the current
was drooping for most of the shot. Density remained low throughout
the discharge, as desired. No locked mode though (judging from
the sawteeth on the x-rays and ECE).

Next shot: no changes.

Shot 05 -- Plasma. Nearly identical to the last shot.

Next shot: on Earl's suggestion, I moved RXL in by approx 1 cm so
that the inner strike point is not right at the bottom edge
of the girdle.

Shot 06 -- Plasma. Same thing.

Next shot: at Earl's insistence, I loaded segment 2 with a
low-density, 0.6 MA shot from 1030612013.

Shot 07 -- Plasma. Full-length shot. Earl suggested this shot based on the
fact that the inner strike point is 1-2 cm above the bottom edge
of the girdle. Not sure why, but it seemed to work.

Next shot: one more without RF

Shot 08 -- Plasma. Good shot. Ip=0.6 MA, nl_04=0.5-0.6e20 m-2.

Next shot: raise density to 0.8e20 m-2, plasma current to 0.8 MA.
Turn on D and E antennas?

John Rice just pointed out to me that the shot I loaded recently does not
have argon puffing, whereas the previous shots did. Maybe that's the real
difference.

Shot 09 -- Plasma. 0.8 MA, nl_04=0.8e20 m-2. Disrupted during rampdown.
Prf(E)=0.5 MW.

Next shot: put in a 30 ms argon puff. It had been 60 ms for
the first 6 shots today, then got switched to 20 ms when I
loaded in the older shot.

Shot 10 -- Plasma. Good shot. Ramped nearly all the way down. Prf=0.8 MW,
but with a lot of trips.

Next shot: no changes.

Shot 11 -- Fizzle.

Next shot: add -10 A to IC_EF4

Shot 12 -- Plasma. Good shot. Very strange density behavior until t=0.77 s,
and there there was some kind of transition to lower density,
higher Te, lower Prad. There was also a brief neutron
enhancement at the transition.

Next shot: no changes

Shot 13 -- Plasma. Good shot. Prf approx 1 MW.

Next shot: no changes

Shot 14 -- Plasma. Good shot. Prf approx 1 MW. DNB is firing at t=0.90 s.
H/D=0.3-0.4

Next shot: no changes

Shot 15 -- Plasma. Good shot. Prf approx 1 MW.

Next shot: CHANGE TO UPPER SINGLE NULL! Load segment 2 from
segment 3 of shot 1030630026.

Shot 16 -- Aborted. Network problems.

Earl is taking over as physop.

Shot 17 -- another cycle test; still having computer problems

Shot 18 -- 0.8 MA upper null (using segment 2); loaded from 1030630026
segment 3.

fizzle; very late breakdown; Bz seems way too positive.

Shot 19 -- add 2 ms to prefill puff (now 21 msec)

no power test; computer problems again

Shot 20 -- add 1 additional ms to prefill puff (now 22 msec)

fizzle

Shot 21 -- reduce prefill puff by 2 msec; now 20 msec

plasma; upper null; disrupt at 0.98 s (dirt)

Shot 22 -- no pcs changes

fizzle; fields look ok

Shot 23 -- no pcs changes
plasma; made it to 1.36 s

next shot: lower prefill puff by 1 msec (to 19)

Shot 24 -- Decrease prefill puff 1 msec (now 19 msec)

fizzle

next shot: no changes

Shot 25 -- no pcs changes

fizzle

next shot, decrease B_r offset by .5 mT to 0.000000 T

Shot 26 -- decrease B_r offset by 0.5 mT to 0.00000 T

dud

next shot: reload 1031010023

Shot 27 -- reload shot 23

fizzle; late breakdown

next shot: increase prefill puff

after shot 27, a problem developed with NFS (file server); PCS would no longer
operate.

End of run.

Session Leader Comments

Physics Operator Comments
Oct 9 2003 04:44:52:977PMRobert GranetzEngineering setup for Friday, 10 Oct 2003

Purpose: Plasma startup and conditioning

Session leader: --
Physics operator: R. Granetz (am) /E. Marmar (pm)
Engineering operator:

ECDC overnight in D2 at 2e-4 Torr, stopping by 07:00.
Bake at 60 C overnight as well.

Run begins at 09:00 and ends at 17:00.

Power systems the same as on 1031009018 (1.0 MA, 5.4 T, lower single null)

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)

Enable the following gate valves, assuming no vacuum problems:
ECE, VUV, DNB

-------------------------------------------------------------------------------
RF Setup: Transmitters 1,2,3, and 4 in RUN ON by 08:00 am

-------------------------------------------------------------------------------
Run Plan: Once we get reliable startup, we'll continue running boring cleanup
plasmas while monitoring H/D, etc. RF Group may start conditioning.

-------------------------------------------------------------------------------
Oct 10 2003 08:22:58:263AMRobert Granetz ECDC was done overnight, as well as a 60 C bake.

Hybrid coldstart done by the engineering group; no errors found

Loaded PCS from shot 1031009019 (1.0 MA, 5.4 T, nl_04=1.0e20 m-2,
single null lower), and reduced Ip to 0.8 MA.
Oct 10 2003 09:13:44:613AM1031010001Robert GranetzShot 01 -- Plasma. Disrupted at t=0.50 s after becoming resistive. Startup
looked good, even though Bz is higher than last campaign.

Next shot: reduce pre-fill by 3 ms.
Oct 10 2003 09:56:33:507AM1031010002Robert GranetzShot 02 -- Plasma. Another short, resistive shot. Disrupted at t=0.48 s.

Next shot: reduce Ip to 0.6 MA, reduce nl_04 to 0.6e20 m-2, and
reduce gas valve voltage preprogramming.
Oct 10 2003 10:17:21:193AM1031010003Robert GranetzShot 03 -- Dud. Problem with OH2U commutation.

Next shot: repeat, no changes.
Oct 10 2003 10:44:04:823AM1031010004Robert GranetzShot 04 -- Plasma. Lasted until t=0.69 s, but even at Ip=0.6 MA the current
was drooping for most of the shot. Density remained low throughout
the discharge, as desired. No locked mode though (judging from
the sawteeth on the x-rays and ECE).

Next shot: no changes.
Oct 10 2003 10:58:21:833AM1031010005Robert GranetzShot 05 -- Plasma. Nearly identical to the last shot.

Next shot: on Earl's suggestion, I moved RXL in by approx 1 cm so
that the inner strike point is not right at the bottom edge
of the girdle.
Oct 10 2003 11:09:40:830AM1031010006Robert GranetzShot 06 -- Plasma. Same thing.

Next shot: at Earl's insistence, I loaded segment 2 with a
low-density, 0.6 MA shot from 1030612013.
Oct 10 2003 11:24:06:073AM1031010007Robert GranetzShot 07 -- Plasma. Full-length shot. Earl suggested this shot based on the
fact that the inner strike point is 1-2 cm above the bottom edge
of the girdle. Not sure why, but it seemed to work.

Next shot: one more without RF
Oct 10 2003 11:29:54:907AM1031010008Robert GranetzShot 08 -- Plasma. Good shot. Ip=0.6 MA, nl_04=0.5-0.6e20 m-2.

Next shot: raise density to 0.8e20 m-2, plasma current to 0.8 MA.
Turn on D and E antennas?
Oct 10 2003 11:38:34:397AM1031010008Robert GranetzJohn Rice just pointed out to me that the shot I loaded recently does not
have argon puffing, whereas the previous shots did. Maybe that's the real
difference.
Oct 10 2003 11:47:08:217AM1031010009Robert GranetzShot 09 -- Plasma. 0.8 MA, nl_04=0.8e20 m-2. Disrupted during rampdown.
Prf(E)=0.5 MW.

Next shot: put in an argon puff.
Oct 10 2003 11:51:40:313AM1031010009Robert GranetzShot 09 -- Plasma. 0.8 MA, nl_04=0.8e20 m-2. Disrupted during rampdown.
Prf(E)=0.5 MW.

Next shot: put in a 30 ms argon puff. It had been 60 ms for
the first 6 shots today, then got switched to 20 ms when I
loaded in the older shot.
Oct 10 2003 12:17:49:803PM1031010011Robert GranetzShot 11 -- Fizzle.

Next shot: add -10 A to IC_EF4
Oct 10 2003 12:34:24:817PM1031010012Robert GranetzShot 12 -- Plasma. Good shot. Very strange density behavior until t=0.77 s,
and there there was some kind of transition to lower density,
higher Te, lower Prad. There was also a brief neutron
enhancement at the transition.

Next shot: no changes
Oct 10 2003 12:44:13:527PM1031010013Robert GranetzShot 13 -- Plasma. Good shot. Prf approx 1 MW.

Next shot: no changes
Oct 10 2003 01:07:57:950PM1031010014Robert GranetzShot 14 -- Plasma. Good shot. Prf approx 1 MW. DNB is firing at t=0.90 s.
H/D=0.3-0.4

Next shot: no changes
Oct 10 2003 01:20:36:303PM1031010015Robert GranetzShot 15 -- Plasma. Good shot. Prf approx 1 MW.

Next shot: CHANGE TO UPPER SINGLE NULL! Load segment 2 from
segment 3 of shot 1030630026.
Oct 10 2003 01:44:03:040PM1031010016Robert GranetzShot 16 -- Aborted. Network problems.
Oct 10 2003 02:11:53:250PM1031010017Robert GranetzEarl is taking over as physop.
Oct 10 2003 02:25:03:630PM1031010017Earl Marmaranother cycle test; still having computer problems
Oct 10 2003 02:30:52:290PM1031010018Earl Marmar0.8 MA upper null (using segment 2); loaded from 1030630026 segment 3.

fizzle; very late breakdown; Bz seems way too positive.
Oct 10 2003 02:46:49:773PM1031010019Earl Marmaradd 2 ms to prefill puff (now 21 msec)

no power test; computer problems again
Oct 10 2003 02:59:13:380PM1031010020Earl Marmaradd 1 additional ms to prefill puff (now 22 msec)

fizzle
Oct 10 2003 03:18:50:740PM1031010021Earl Marmarreduce prefill puff by 2 msec; now 20 msec

plasma; upper null; disrupt at 0.98 s (dirt)
Oct 10 2003 03:25:05:680PM1031010022Earl Marmarno pcs changes

fizzle; fields look ok
Oct 10 2003 03:46:53:897PM1031010023Earl Marmarno pcs changes
plasma; made it to 1.36 s

next shot: lower prefill puff by 1 msec (to 19)
Oct 10 2003 03:51:54:227PM1031010024Earl MarmarDecrease prefill puff 1 msec (now 19 msec)

fizzle

next shot: no changes
Oct 10 2003 04:05:40:757PM1031010025Earl Marmarno pcs changes

fizzle

next shot, decrease B_r offset by .5 mT to 0.000000 T
Oct 10 2003 04:23:46:913PM1031010026Earl Marmardecrease B_r offset by 0.5 mT to 0.00000 T

dud

next shot: reload 1031010023
Oct 10 2003 04:45:41:070PM1031010027Earl Marmarreload shot 23

fizzle; late breakdown

next shot: increase prefill puff
Oct 10 2003 05:08:07:367PM1031010027Earl Marmarafter shot 27, a problem developed with NFS (file server); PCS would no longer operate.

End of run.

Engineering Operator Comments
ShotTimeTypeStatusComment
109:07:52:250AMPlasmaBadOH1 self powered crkt fired
209:47:07:670AMPlasmaBadOH1 Fault
310:08:26:970AMPlasmaBadNo OH2 Commutation to missed reset
410:31:15:597AMPlasmaOk
510:44:29:450AMPlasmaOk
610:58:56:727AMPlasmaOk
711:11:44:673AMPlasmaOk
811:25:09:887AMPlasmaOk
911:40:03:367AMPlasmaOk
1011:53:13:097AMPlasmaOk
1112:06:41:293PMPlasmaOk
1212:20:15:913PMPlasmaOk
1312:40:33:460PMPlasmaOk
1412:56:08:940PMPlasmaOk
1501:09:06:000PMPlasmaOk
1601:27:01:573PMTestOk
1702:08:15:933PMTestOk
1802:25:51:443PMTestBad
1902:39:36:443PMTestOk
2002:55:17:837PMPlasmaOk
2103:08:54:787PMPlasmaOk
2203:21:35:367PMPlasmaOk
2303:34:24:023PMPlasmaOk
2403:48:06:007PMPlasmaOk
2504:00:52:693PMPlasmaOk
2604:18:48:943PMPlasmaOk
2704:31:36:430PMPlasmaOk