Alcator C-Mod Run 1010718 Information

Back to runs

Miniproposals
Miniproposal:289a
Date Filed: 5/2/2001
Title:Investigations of Double Transport Barrier Plasmas
First Author:John Rice
Session Leader:John Rice (shots 1-14)

Operators
Session leader(s):John Rice
Physics operator(s):Robert Granetz
Engineering operator(s):Bill Parkin,Ed Fitzgerald,Bill Cochran

Engineering Operator Run Comment
MP#289A Double Barrier,MP#137 L-H-L transitionsSL:Rice,Hubbard PO:Granet

Session Leader Plans

Physics Operators Plans

Session Leader Summaries
Entered: Jul 7 2004 03:49:27:383PM
Author: To Be Determined
Session Leader Run Summary for 1010718 MP289A Double Barrier Studies

Again several double barrier plasmas were formed at 4.5 T using D and E port;
however J-port was essentially unavailable so not much headway was made into
MP289A. The run began late, with the first plasma after 1 PM. Most of the shots
were spent trying to arrest the density and impurity increase by reramping the
TF, similar to shot 1010717017 but all plasmas suffered H-L transitions which
destroyed the ITBs. Perhaps the problem was due to high radiation.

Physics Operator Summaries
Entered: Jul 7 2004 04:37:13:880PM
Author: To Be Determined
Physics operator summary for run 1010718 (Wednesday):

MP #289A -- Double Barrier
MP #137 -- L-H-L transitions (standby)

Session leader: J. Rice (A. Hubbard for standby MP)
Physics operator: R. Granetz
Engineer: W. Cochran/E. Fitzgerald/W. Parkin

Summary: We stayed with MP #289A for the whole run, but plasma operation didn't
begin until 13:00, because a failed OH2 shunt had to be removed.
When we finally did get going, the machine ran well, with only 2
fizzles and no duds. We did ECDC between nearly all shots. Most
of the PCS work today involved varying the temporal behavior of the
toroidal field, using varies rampups from 4.5 to 5.4 T. This had
a noticeable effect on the H-L back-transition. See John Rice's
run summary for more details. H/D was kept at 8% for shots with 2 MW
of RF, 10% for shots with 2.5 MW (all from D and E antennas).
J-antenna only got up to 300 kW for short pulses.

Scorecard: 10 plasmas
2 fizzles
0 duds
2 tests
0 aborted and/or screwed up by computer problems
----------
14 total

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

Engineering setup for Wednesday 18 July 2001

ECDC in D2 overnight, stopping by 8:00 am.

*******************************************************************************
* If the ICRF does vacuum conditioning of J-port before the run, we will *
* want to do at least 30 minutes of ECDC in D2 just prior to plasma *
* operation. *
*******************************************************************************

Run begins at 09:00 and ends at 17:00, unless there are delays required by
the pumping/purging of the J-port line.

Power systems the same as for shot 1010717016.

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)
fill J-Bottom with 30 psi He Hybrid DISABLED(PG5)

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

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

RF Setup:

Transmitters 1 and 2 in run-on started at 08:00.
Transmitters 3 and 4 in run-on started at 08:00.

RF Waveforms: same as on 1010717016 (2+ MW from D+E, flat from t=0.6 to 1.5 s

-------------------------------------------------------------------------------
Run Plan:

Pick up where we left off on Tuesday. Start with shot 1010717016. Try to
optimize the off-axis core barrier with D and E at 80 MHz.

J-port tuning at 70 MHz will be done in background (i.e. toward the end of
each shot).

If the double barrier experiments are completed and J-port is not ready to
proceed, then Amanda's MP #137 (L-H-L transitions) will be started.

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

Overnight ECDC in D2 was done.

Hybrid coldstart done; no errors found

Loaded PCS from shot 1010717016, no changes made.

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

The start of the run is delayed to 10:00 in order to fix an OH2 shunt, and
to work on the RF.

The first shot will be a 10 kA OH test to check the new shunt.

Shot 01 -- Test. No-power shot cycle. PF fault occurred during INIT.

Next shot: OH test (with power)

Shot 02 -- Test. 10 kA OH test to check the new shunt. All OK.

Next shot: go for plasma, after first doing 20 minutes of ECDC
(J-port did some vacuum conditioning this morning.)

20 minutes of ECDC in D2.

Shot 03 -- Fizzle.

Next shot: increase pre-fill puff by 2 ms.

ECDC in D2 between shots.

Shot 04 -- Plasma. Good shot. Ip=0.8 MA, Btor=4.5 T, nl_04(target)=1.0e20 m-2
Good core barrier. Prf=2 MW, equally from D and E.

Next shot: ramp Btor back up to 5.4 T starting at t=0.85 s (like
shot 17 from yesterday). Also reduce pre-fill puff by 1 ms.

ECDC in D2 between shots.

Shot 05 -- Plasma. Disrupted at t=0.62 s, just after the RF turns on. Looks
like an impurity injection killed it. Nothing seen in the wide
angle camera view.

Next shot: try again, no changes.

ECDC in D2 between shots.

Shot 06 -- Plasma. Good shot. Btor ramps back up and reaches 5.4 T at
t=1.0 s. Short ITB, followed by a standard EDA. Prf=2.0 MW.

Next shot: repeat, no changes

ECDC in D2 between shots.

Short cell access for TS, DNB, XTOMO

Shot 07 -- Plasma. Good shot. Virtually identical ITB and EDA behavior as
the previous shot. H/D has been holding at 8% during the RF
pulse for all of the plasmas today.

Next shot: move Btor rampup earlier by 100 ms, to see whether this
has something to do with triggering the end of the ITB.

ECDC in D2 between shots.

Shot 08 -- Plasma. Disrupted at t=1.40 s. ITB H-L back transition is earlier
on this shot, seemingly caused by the Btor rampup.

Next shot: cut the Btor ramp rate. (Start rampup at t=0.75, as
before, but end the rampup at t=1.10 s.)

ECDC in D2 between shots.

Shot 09 -- Fizzle. Weak. Pressure is high.

Next shot: reduce pre-fill puff by 2 ms.

No ECDC in D2 between shots this time.

Shot 10 -- Plasma. Back-transition happened a little later this time.
No H/D signal this shot.

Next shot: start Btor rampup at t=0.85 and stop it at t=1.50. This
cuts the ramp rate nearly in half again.

ECDC in D2 between shots.

Shot 11 -- Plasma. Good shot. Prf=2.0 MW from D and E. H/D=8-10%.

Next shot: get rid of Btor rampup entirely (stay at 4.5 T)

ECDC in D2 between shots.

Shot 12 -- Plasma. Good shot. Only one H-mode/ITB. H/D=8%. Prf=2.0 MW (D+E)

Next shot: reset Btor to be the same as on shot 10 (start rampup
at t=0.75 and stop rampup at t=1.10 s

ECDC in D2 between shots.

Shot 13 -- Plasma. Disrupted at t=1.18 s. Looks like an impurity injection.
Three H-modes. Prf=2.5 MW, but there were a lot of faults.
Wide-angle camera shows an obvious bright spot at the top of
D-antenna on the frame before the disruption.

Next shot: raise target density by 10% (to nl_04=1.1e20 m-2)

ECDC in D2 between shots.

Shot 14 -- Plasma. Good shot. Prf=2.5 MW, but E faulted alot. H/D=8-10%

End of run.

Session Leader Comments
Jul 18 2001 12:32:15:870PM1010718003John Ricefiz
Jul 18 2001 01:14:30:373PM1010718004John Ricegood ITB
no J-port
Jul 18 2001 01:33:58:363PM1010718005John Ricedisrupted at 0.6s
Jul 18 2001 02:05:31:470PM1010718006John RiceITB, with TF reramp, but H-L at 0.9 s
Jul 18 2001 02:41:05:977PM1010718007John RiceITB, with TF reramp, but H-L at 0.9 s
Jul 18 2001 02:43:44:030PM1010718007John RiceITB, with TF reramp earlier, and H-L also earlier at 0.8 s
Jul 18 2001 02:57:57:603PM1010718008John RiceITB, with TF reramp earlier, and H-L also earlier at 0.8 s
Jul 18 2001 03:06:33:230PM1010718009John Ricefiz
Jul 18 2001 03:23:36:183PM1010718010John RiceITB, slower TF ramp, but still H-L at 0.8 s
Jul 18 2001 03:57:23:470PM1010718011John RiceITB, slower TF ramp, but still H-L at 0.88 s
Jul 18 2001 04:17:26:960PM1010718012John RiceITB, no TF ramp, but still H-L at 0.88 s
Jul 18 2001 04:40:40:550PM1010718013John RiceITB, TF ramp, but still H-L at 0.8 s
Jul 18 2001 05:04:19:847PM1010718014John RiceITB, raised density, TF ramp, but still H-L at 0.8 s

Physics Operator Comments
Jul 18 2001 09:12:15:127AMRobert GranetzEngineering setup for Wednesday 18 July 2001

ECDC in D2 overnight, stopping by 8:00 am.

*******************************************************************************
* If the ICRF does vacuum conditioning of J-port before the run, we will *
* want to do at least 30 minutes of ECDC in D2 just prior to plasma *
* operation. *
*******************************************************************************

Run begins at 09:00 and ends at 17:00, unless there are delays required by
the pumping/purging of the J-port line.

Power systems the same as for shot 1010717016.

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)
fill J-Bottom with 30 psi He Hybrid DISABLED(PG5)

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

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

RF Setup:

Transmitters 1 and 2 in run-on started at 08:00.
Transmitters 3 and 4 in run-on started at 08:00.

RF Waveforms: same as on 1010717016 (2+ MW from D+E, flat from t=0.6 to 1.5 s

-------------------------------------------------------------------------------
Run Plan:

Pick up where we left off on Tuesday. Start with shot 1010717016. Try to
optimize the off-axis core barrier with D and E at 80 MHz.

J-port tuning at 70 MHz will be done in background (i.e. toward the end of
each shot).

If the double barrier experiments are completed and J-port is not ready to
proceed, then Amanda's MP #137 (L-H-L transitions) will be started.
Jul 18 2001 09:12:43:707AMRobert Granetz Overnight ECDC in D2 was done.

Hybrid coldstart done; no errors found

Loaded PCS from shot 1010717016, no changes made.
Jul 18 2001 09:12:51:567AMRobert GranetzThe start of the run is delayed to 10:00 in order to fix an OH2 shunt, and
to work on the RF.
Jul 18 2001 11:02:39:243AMRobert GranetzThe first shot will be a 10 kA OH test to check the new shunt.
Jul 18 2001 11:40:21:850AM1010718001Robert GranetzShot 01 -- Test. No-power shot cycle. PF fault occurred during INIT.

Next shot: OH test (with power)
Jul 18 2001 11:55:12:080AM1010718002Robert GranetzShot 02 -- Test. 10 kA OH test to check the new shunt. All OK.

Next shot: go for plasma, after first doing 20 minutes of ECDC
(J-port did some vacuum conditioning this morning.)

20 minutes of ECDC in D2.
Jul 18 2001 12:38:12:100PM1010718003Robert GranetzShot 03 -- Fizzle.

Next shot: increase pre-fill puff by 2 ms.

ECDC in D2 between shots.
Jul 18 2001 02:06:30:850PM1010718004Robert GranetzShot 04 -- Plasma. Good shot. Ip=0.8 MA, Btor=4.5 T, nl_04(target)=1.0e20 m-2
Good core barrier. Prf=2 MW, equally from D and E.

Next shot: ramp Btor back up to 5.4 T starting at t=0.85 s (like
shot 17 from yesterday). Also reduce pre-fill puff by 1 ms.

ECDC in D2 between shots.
Jul 18 2001 01:36:23:993PM1010718005Robert GranetzShot 05 -- Plasma. Disrupted at t=0.62 s, just after the RF turns on. Looks
like an impurity injection killed it. Nothing seen in the wide
angle camera view.

Next shot: try again, no changes.

ECDC in D2 between shots.
Jul 18 2001 02:05:40:173PM1010718006Robert GranetzShot 06 -- Plasma. Good shot. Btor ramps back up and reaches 5.4 T at
t=1.0 s. Short ITB, followed by a standard EDA. Prf=2.0 MW.

Next shot: repeat, no changes

ECDC in D2 between shots.

Short cell access for TS, DNB, XTOMO
Jul 18 2001 03:38:26:930PM1010718007Robert GranetzShot 07 -- Plasma. Good shot. Virtually identical ITB and EDA behavior as
the previous shot. H/D has been holding at 8% during the RF
pulse for all of the plasmas today.

Next shot: move Btor rampup earlier by 100 ms, to see whether this
has something to do with triggering the end of the ITB.

ECDC in D2 between shots.
Jul 18 2001 02:47:51:757PM1010718008Robert GranetzShot 08 -- Plasma. Disrupted at t=1.40 s. ITB H-L back transition is earlier
on this shot, seemingly caused by the Btor rampup.

Next shot: cut the Btor ramp rate. (Start rampup at t=0.75, as
before, but end the rampup at t=1.10 s.)

ECDC in D2 between shots.
Jul 18 2001 03:13:14:430PM1010718009Robert GranetzShot 09 -- Fizzle. Weak. Pressure is high.

Next shot: reduce pre-fill puff by 2 ms.

No ECDC in D2 between shots this time.
Jul 18 2001 03:36:53:930PM1010718010Robert GranetzShot 10 -- Plasma. Back-transition happened a little later this time.
No H/D signal this shot.

Next shot: start Btor rampup at t=0.85 and stop it at t=1.50. This
cuts the ramp rate nearly in half again.

ECDC in D2 between shots.
Jul 18 2001 04:04:57:810PM1010718011Robert GranetzShot 11 -- Plasma. Good shot. Prf=2.0 MW from D and E. H/D=8-10%.

Next shot: get rid of Btor rampup entirely (stay at 4.5 T)

ECDC in D2 between shots.
Jul 18 2001 04:28:12:497PM1010718012Robert GranetzShot 12 -- Plasma. Good shot. Only one H-mode/ITB. H/D=8%. Prf=2.0 MW (D+E)

Next shot: reset Btor to be the same as on shot 10 (start rampup
at t=0.75 and stop rampup at t=1.10 s

ECDC in D2 between shots.
Jul 18 2001 05:52:35:767PM1010718013Robert GranetzShot 13 -- Plasma. Disrupted at t=1.18 s. Looks like an impurity injection.
Three H-modes. Prf=2.5 MW, but there were a lot of faults.
Wide-angle camera shows an obvious bright spot at the top of
D-antenna on the frame before the disruption.

Next shot: raise target density by 10% (to nl_04=1.1e20 m-2)

ECDC in D2 between shots.
Jul 18 2001 05:34:42:310PM1010718014Robert GranetzShot 14 -- Plasma. Good shot. Prf=2.5 MW, but E faulted alot. H/D=8-10%

End of run.

Engineering Operator Comments
ShotTimeTypeStatusComment
111:35:17:747AMTestBadOH PLC Test, Aborted due to erroneous OH2L type 1 flt
211:49:43:150AMTestOkOH PLC Test
312:24:11:073PMPlasmaOk
412:56:11:573PMPlasmaOk
501:23:03:360PMPlasmaOk
601:47:13:937PMPlasmaOk
702:12:26:330PMPlasmaOk
802:37:37:127PMPlasmaOk
903:03:03:723PMPlasmaOk
1003:18:06:783PMPlasmaOk
1103:48:43:327PMPlasmaOk
1204:15:03:000PMPlasmaOk
1304:38:06:390PMPlasmaOk
1405:02:18:500PMPlasmaOk