Alcator C-Mod Run 990722 Information

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Miniproposals
Miniproposal:214
Date Filed: 1/5/1999
Title:D and E-port RF System Commissioning
First Author:Steve Wukitch
Session Leader:Steve Wukitch (shots 1-20)

Operators
Session leader(s):Steve Wukitch
Physics operator(s):Robert Granetz
Engineering operator(s):Frank Silva

Engineering Operator Run Comment
RF ConditioningNULLGranetz, Silva

Session Leader Plans

Physics Operators Plans

Session Leader Summaries

Physics Operator Summaries
Entered: Jul 7 2004 04:37:04:973PM
Author: To Be Determined
Physics operator summary for run 990722:

MP 214 -- RF conditioning

SL: Dr. Wukitch, I presume?
PO: R. Granetz

The goal for today:

Re-establish plasma operation and condition the ICRF.

Summary: It was a really tough day ... predominantly duds, interspersed with
a few plasmas, and even a fizzle. Throughout the day, the null looked
decent, and variations in Br0, Bz0, and pre-fill did not seem to
increase the probability of success with any consistency, although
there were no duds at the highest pre-fill pressures (i.e. pre-fill
pulse width > 30 ms)

On the positive side, both D and E systems were able to operate
simultaneously, coupling up to a total of 1.5 MW on shot 990722017.
This shot had a pre-fill pulse width of 32 ms, and is probably a good
one to start from tomorrow.

Scorecard: 6 plasmas
1 fizzles
13 duds (0 due to lack of one or more power supplies)
0 tests
0 aborted
----------
20 total

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

Engineering Setup for Thursday, 990722:

Load from 990721009 (or similar shot from Wednesday).

Overnight ECDC in D2 prior to run, with Steve Wukitch stopping the ECDC when
he wants to pulse RF, and turning it back on again when he's done.

Gas setup - fill B-top with 6 psi of D2 Hybrid enabled
fill B-side lower with 1 psi of Ar Hybrid DISABLED
fill B-side upper with 6 psi of H2 Hybrid DISABLED
fill C-side with 30 psi of D2 Hybrid enabled
leave J-bottom as is Hybrid DISABLED

The following gate valves should be enabled, assuming no vacuum problems:

ECE, VUV

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

Run Plan for 990722:

MP 214 -- RF conditioning

SL: Dr. Wukitch, I presume?
PO: R. Granetz

Start by loading 990721009. Optimise outer gap for RF coupling.

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

Note: overnight ECDC in D2 was done prior to this run.

Hybrid coldstart done; no errors found
($set default cmod$models:[hybrid.tcl]
$@hybinit_dispatch
$@show_bitbus_log
Use editor search to verify no occurrences of "error" nor
"not respond")
Load 990721009, add 0.5 mT to Br0 and reduce pre-puff from 25 to 22 ms.

Shot 01 -- Plasma. Good shot. 0.8 MA, 5.4 T, nl_04=1.0e20 m-2, ramped all
the way down, terminating at 1.83 s. Flattop to 1.4 s.
Right gap = 12 mm. There were a number of injections throughout
the shot. Prf=0.8 MW, all from D-port.

Next shot: reduce outboard gap to 10 mm (by increasing RCUR 1 mm)

Shot 02 -- Dud. Null looked very good. Pre-fill okay also.

Next shot: just try again with no changes

Shot 03 -- Dud. Bz is creeping up and Br is creeping down.

Next shot: increase Br0 offset by 1 mT.

Shot 04 -- Dud.

Next shot: increase pre-fill puff from 22 to 28 ms.

Shot 05 -- Dud.

Begin ECDC between shots, starting now.

Next shot: also reduce Br0 by 0.5 mT, and reduce pre-fill pulse
from 28 to 25 ms.

Shot 06 -- Dud.

Earl and Steve say "reduce Br0"

Next shot: reduce Br0 by 1.5 mT

Shot 07 -- Dud.

Next shot: try reducing Bz0 (change IC_EF4U from -1285 to -1300 A),
and reduce gas puff from 25 to 20 ms.

Shot 08 -- Dud.

Next shot: try raising Bz0 (change IC_EF4U from -1300 to -1270 A),
and set gas puff at 22 ms.

Shot 09 -- Dud.

Next shot: reload shot 01

Shot 10 -- Plasma. Good shot. 0.8 MA, 5.4 T, nl_04=1.0e20 m-2, ramped all
the way down, terminating at 1.83 s. Flattop to 1.4 s.
Right gap = 10-11 mm. There were a number of large injections
throughout the shot. Prf=1.3 MW, mostly from E-port, but D-port
also ran. Short H-mode around t=0.7 s. Br0 was slightly less
than on shot 01.

Next shot: raise nl_04 slightly (from 1.0 to 1.1e20 m-2) (only in
segment 2)

Shot 11 -- Plasma. Disrupted at 0.32 s, after going vertically unstable.
There was a big injection starting at 0.28 s, which turned the
current over and may be the reason for the vertical stability
problems.

Next shot: no changes

Shot 12 -- Plasma. Disrupted at 0.27 s, just as it was about to divert. The
plasma may be just touching the inner divertor nose.

Next shot: keep nl_04 at 1.0e20 m-2 until after t=0.5 s (then
it goes to 1.1e20 m-2)

Shot 13 -- Dud. Null was reasonable.

Next shot: no changes.

Shot 14 -- Dud. Null was reasonable, but Bz was a little higher on the last
two shots compared to shot 10.

Next shot: reduce Bz (change IC_EF4U from -1285 to -1300 A), and
redefine processed flux_14 to use F29 instead of F15.

Shot 15 -- Dud. Null looked really good, since Bz was nulled out better.

Next shot: reduce pre-fill pulse to 15 ms (just to do something).

Shot 16 -- Dud. Well, lowering the pre-fill didn't do it.

Next shot: try raising pre-fill to 32 ms, and enable the argon

Shot 17 -- Plasma. Good shot. 2 H-modes, with ITB at H-L transition.
Prf=1.5 MW (1 MW from E, and 0.5 MW from D). Right gap = 1.0 cm.

Next shot: no PCS changes. Change processed flux_14 to use F15
instead of F29.

Shot 18 -- Fizzle. Late breakdown.

Next shot: reduce pre-fill pulse from 32 to 28 ms.

Shot 19 -- Dud.

Next shot: increase pre-fill pulse to 35 ms.

Shot 20 -- Plasma. Disrupted at t=0.33 s due to vertical instability.

End of run.

Session Leader Comments
Jul 22 1999 09:48:39:653AMSteve Wukitch
MP 214: RF conditioning


All transmitters are ready to be tested into plasma.

We will have #2 in as yesterday at ~1MW level.
#1 breaker is working and we will bring that one online.
#4 is goint to antenna.
#3 is going first into dummy load to start it then to antenna.

Minor tweaks will be performed to plasmas in order to optimize
the RF tuning.

Jul 22 1999 10:33:02:797AM990722001Steve Wukitch

Plasma,

D antenna ran up to ~800 kW.

J3 went into dummy load
J4 was still at low power (few kW)

Jul 22 1999 01:38:43:683PM990722010Steve Wukitch

Plasma,

D antenna ran up to ~600 kW. (second pulse)
E antenna ran up to 1.3MW (first pulse) small H mode

J3 just got nixed (gate off) before it put power into machine
J4 was still at low power (few kW), (third pulse)

Jul 22 1999 04:19:00:560PM990722017Steve Wukitch

Plasma,

D antenna ran up to ~600 kW. (second pulse)
E antenna ran up to 1.3MW (first pulse), together and H modes

J3 not quite putting power in machine, otherwise running (last pulse)
J4 was still at low power (40 kW), (third pulse)

Physics Operator Comments
Jul 22 1999 09:28:32:607AMRobert GranetzEngineering Setup for Thursday, 990722:

Load from 990721009 (or similar shot from Wednesday).

Overnight ECDC in D2 prior to run, with Steve Wukitch stopping the ECDC when
he wants to pulse RF, and turning it back on again when he's done.

Gas setup - fill B-top with 6 psi of D2 Hybrid enabled
fill B-side lower with 1 psi of Ar Hybrid DISABLED
fill B-side upper with 6 psi of H2 Hybrid DISABLED
fill C-side with 30 psi of D2 Hybrid enabled
leave J-bottom as is Hybrid DISABLED

The following gate valves should be enabled, assuming no vacuum problems:

ECE, VUV
Jul 22 1999 09:28:53:263AMRobert GranetzRun Plan for 990722:

MP 214 -- RF conditioning

SL: Dr. Wukitch, I presume?
PO: R. Granetz

Start by loading 990721009. Optimise outer gap for RF coupling.
Jul 22 1999 09:29:09:123AMRobert Granetz Note: overnight ECDC in D2 was done prior to this run.

Hybrid coldstart done; no errors found
($set default cmod$models:[hybrid.tcl]
$@hybinit_dispatch
$@show_bitbus_log
Use editor search to verify no occurrences of "error" nor
"not respond")
Load 990721009, add 0.5 mT to Br0 and reduce pre-puff from 25 to 22 ms.
Jul 22 1999 10:49:39:513AM990722001Robert GranetzShot 01 -- Plasma. Good shot. 0.8 MA, 5.4 T, nl_04=1.0e20 m-2, ramped all
the way down, terminating at 1.83 s. Flattop to 1.4 s.
Right gap = 12 mm. There were a number of injections throughout
the shot. Prf=0.8 MW, all from D-port.

Next shot: reduce outboard gap to 10 mm (by increasing RCUR 1 mm)
Jul 22 1999 10:28:03:357AM990722002Robert GranetzShot 02 -- Dud. Null looked very good. Pre-fill okay also.

Next shot: just try again with no changes
Jul 22 1999 11:07:11:200AM990722003Robert GranetzShot 03 -- Dud. Bz is creeping up and Br is creeping down.

Next shot: increase Br0 offset by 1 mT.
Jul 22 1999 11:19:24:577AM990722004Robert GranetzShot 04 -- Dud.

Next shot: increase pre-fill puff from 22 to 28 ms.
Jul 22 1999 11:36:13:327AM990722005Robert GranetzShot 05 -- Dud.

Begin ECDC between shots, starting now.

Next shot: also reduce Br0 by 0.5 mT
Jul 22 1999 12:07:44:090PM990722006Robert GranetzShot 06 -- Dud.

Earl and Steve say "reduce Br0"

Next shot: reduce Br0 by 1.5 mT
Jul 22 1999 12:22:32:327PM990722007Robert GranetzShot 07 -- Dud.

Next shot: try reducing Bz0 (change IC_EF4U from -1285 to -1300 A),
and reduce gas puff from 25 to 20 ms.
Jul 22 1999 12:42:06:967PM990722008Robert GranetzShot 08 -- Dud.

Next shot: try raising Bz0 (change IC_EF4U from -1300 to -1270 A),
and set gas puff at 22 ms.
Jul 22 1999 12:54:12:763PM990722009Robert GranetzShot 09 -- Dud.

Next shot: reload shot 1
Jul 22 1999 01:26:10:060PM990722010Robert GranetzShot 10 -- Plasma. Good shot. 0.8 MA, 5.4 T, nl_04=1.0e20 m-2, ramped all
the way down, terminating at 1.83 s. Flattop to 1.4 s.
Right gap = 10-11 mm. There were a number of large injections
throughout the shot. Prf=1.3 MW, mostly from E-port, but D-port
also ran. Short H-mode around t=0.7 s. Br0 was slightly less
than on shot 01.

Next shot: raise nl_04 slightly (from 1.0 to 1.1e20 m-2) (only in
segment 2)
Jul 22 1999 02:11:58:983PM990722011Robert GranetzShot 11 -- Plasma. Disrupted at 0.32 s, after going vertically unstable.
There was a big injection starting at 0.28 s, which turned the
current over and may be the reason for the vertical stability
problems.

Next shot: no changes
Jul 22 1999 02:12:06:857PM990722012Robert GranetzShot 12 -- Plasma. Disrupted at 0.27 s, just as it was about to divert. The
plasma may be just touching the inner divertor nose.

Next shot: keep nl_04 at 1.0e20 m-2 until after t=0.5 s (then
it goes to 1.1e20 m-2)
Jul 22 1999 02:28:17:230PM990722013Robert GranetzShot 13 -- Dud. Null was reasonable.

Next shot: no changes.
Jul 22 1999 03:05:56:483PM990722014Robert GranetzShot 14 -- Dud. Null was reasonable, but Bz was a little higher on the last
two shots compared to shot 10.

Next shot: reduce Bz (change IC_EF4U from -1285 to -1300 A), and
redefine processed flux_14 to use F29 instead of F15.
Jul 22 1999 03:16:04:060PM990722015Robert GranetzShot 15 -- Dud. Null looked really good, since Bz was nulled out better.

Next shot: reduce pre-fill pulse to 15 ms (just to do something).
Jul 22 1999 03:36:12:797PM990722016Robert GranetzShot 16 -- Dud. Well, lowering the pre-fill didn't do it.

Next shot: try raising pre-fill to 32 ms
Jul 22 1999 04:15:58:403PM990722017Robert GranetzShot 17 -- Plasma. Good shot. 2 H-modes, with ITB at H-L transition.
Prf=1.5 MW (1 MW from E, and 0.5 MW from D). Right gap = 1.0 cm.

Next shot: no PCS changes. Change processed flux_14 to use F15
instead of F29.
Jul 22 1999 04:29:44:230PM990722018Robert GranetzShot 18 -- Fizzle. Late breakdown.

Next shot: reduce pre-fill pulse from 32 to 28 ms.
Jul 22 1999 04:44:20:000PM990722019Robert GranetzShot 19 -- Dud.

Next shot: increase pre-fill pulse to 35 ms.
Jul 22 1999 05:15:32:170PM990722020Robert GranetzShot 20 -- Plasma. Disrupted at t=0.33 s due to vertical instability.

End of run.

Engineering Operator Comments
ShotTimeTypeStatusComment
109:48:31:500AMPlasmaOkno faults/plasma
210:21:33:653AMPlasmaOkno faults
310:56:26:077AMPlasmaOkno faults
411:10:05:890AMPlasmaOkno faults
511:26:18:293AMPlasmaOkno faults
611:50:10:387AMPlasmaOkno faults
712:15:48:687PMPlasmaOkno faults
812:35:53:297PMPlasmaOkno faults
912:50:33:827PMPlasmaOkno faults
1001:06:35:480PMPlasmaOkno faults
1101:35:39:437PMPlasmaOkno faults
1202:00:51:797PMPlasmaOkno faults
1302:20:34:280PMPlasmaOkno faults
1402:43:15:217PMPlasmaOkNo faults
1503:10:17:733PMPlasmaOkNo Faults
1603:28:34:530PMPlasmaOkNo faults
1704:00:28:750PMPlasmaOk(null)
1804:21:23:543PMPlasmaOkno faults
1904:41:43:920PMPlasmaOkNo Plasma
2004:59:17:653PMPlasmaOkNo Faults