Alcator C-Mod Run 1010716 Information

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Miniproposals
Miniproposal:289a
Date Filed: 5/2/2001
Title:Investigations of Double Transport Barrier Plasmas
First Author:John Rice
Session Leader:John Rice (shots 1-18)

Operators
Session leader(s):John Rice
Physics operator(s):Joseph Snipes
Engineering operator(s):Bill Cochran

Engineering Operator Run Comment
MP 289A Double Barrier. Rice/Snipes/Cochran

Session Leader Plans

Physics Operators Plans

Session Leader Summaries
Entered: Jul 7 2004 03:49:26:993PM
Author: To Be Determined
Run Summary for Monday July 16, 2001

RF Conditioning
MP289A: Double Barrier Experiments
SL: Rice
PO: Snipes

The run was scheduled to start at 10:00 AM. First plasma was at
approximately 11:15 AM and the run ended at 5:00 PM.

Shots 001 - 009 were devoted to RF Conditioning at 5.3 T.
Shots 010 - 018 were devoted to recovering the ITB barrier mode
at 4.5 T. Very slow but steady progress was made throughout the
day, especially considering the late start time of the run.

A. RF Conditioning Phase

The D- and E- antenna / xmtr systems ran well at both 5.3T and 4.5T.
We were finally able to get a shot at 5.3 T where D-, E-, and
J-antenna sysrtems all ran through simultaneously at 2.8 MW (see Shot
1010716008). However, J-port still needs further conditioning as
evidenced in part by the fact that we were not able to get it to
stay on even at lower power (0.6 MW) at 4.5T. There also appears to be
a problem with the de-coupling stub on J-port.

The H/D fraction was on the high side all day with H/D starting at
0.06-0.08 and rising throughout the shots.

B. ITB Studies

Attempts to recover the density barrier mode at 4.5T were partially
successful. As an example, on shot 1010716012 we got a transition into
an EDA H-mode phase with strong density peaking [n_e(TS) = 5.75 X
10^20 m^{-3}]. In subsequent shots however, the H-mode / ITB phase was
killed by radiation. The target density was raised to nl_04 = 1.0 X
10^20 to mitigate the radiative collapse (borrowing from our
experience during the December, 2000 ITB run campaign). But this did
not seem to work. We also increased the discharge triangularity in
order to be closer to the conditions under which we produced the
density barrier in December, 2000 (see 1001220016). As a general
observation, the EDA H-modes today were not the greatest in the sense
that there was significant radiative build-up even in the 5.3 T
H-modes (see 101071608).

Conclusion: The machine may need more conditioning before we can
reproduce the density barrier mode without back transitions.

Physics Operator Summaries
Entered: Jul 7 2004 04:37:13:850PM
Author: To Be Determined
Run Plan and ENGINEERING SETUP FOR Monday 1010716

MP289A Double Barrier
SL: Rice
PO: Snipes

ECDC in D2 over the weekend with a 60 C bake stopping at 8:00 am

RUN BEGINS AT 10:00 AND ENDS AT 5:00

Power systems the same as for shot 1010713022

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 6 psi He Hybrid DISABLED(PG5)
Enable the following gate valves, assuming no vacuum problems:
ECE, DNB, VUV

RF STATUS:

XMTR 1 AND 2, RUN-ON STARTED AT 8:00 AM
XMTR 3 AND 4, RUN-ON STARTED AT 8:00 AM

RUN PLAN:

RF antenna conditioning for the first couple of hours to determine
if the RF is far enough along to begin MP289A ITB studies.
In the event of RF problems, fall back MP's include:
MP259 MSE calibration (beam into gas with field) Yuh
MP137 L-H-L transitions Hubbard
MP233 Density Limits [g],laBombard
Piggybacking by MP281 Edge Turbulence Imaging is expected on any
of the above except MP259.

Run Delayed until 11:15 due to RF maintenance.

Summary: The machine ran reasonably well, although there were a half dozen
fizzles due to difficulties in tuning up the fields and gas, particularly the
gas at breakdown. The RF ran so-so with about 2 MW typically, sometimes
reasonably steady, but sometimes tripping. The ITB's were not generated under
these rather non-stationary multiple H-mode conditions. So, the MP will
continue tomorrow. The H/(H+D) ratio was not too bad, starting at 4 - 5 %, but
it did climb some during the longer RF pulses to 10% or so. Between shot ECDC
in D2 helped, but some care needs to be taken to allow the gas to pump out
before going to INIT.
1 0.000 0.032 2 0.000 0.037
3 0.000 0.045 4 1.948 0.792
5 1.944 0.792 6 1.911 0.789
7 1.194 0.805 8 1.919 0.802
9 1.892 0.797 10 0.000 0.032
11 0.000 0.003 12 1.871 0.789
13 0.000 0.029 14 1.848 0.797
15 0.000 0.032 16 1.862 0.797
17 1.892 0.802 18 1.918 0.805

Finished summary for 1010716 Total of 18 shots.
18 shots. 11 plasmas. 6 fizzles. 1 test


Shot 1: Start from 1010713022 with no changes to see how well the RF performs.
Fizzle!
Shot 2: Raised Br0 by 0.5 mT to 0.5 mT and increased EF4 current from -1290 A
to -1270 A. Try again. Wrong way on Br0. My mistake. Fizzle again!
Shot 3: Raised Br0 by 1 mT to 1.5 mT. Fizzle again!
Shot 4: Raise Br0 by another 0.5 mT to 2 mT and decrease prepuff from 24 ms
to 21 ms duration. Good shot. Full length plasma with EDA H-mode from 1.07 s
to 1.55 s. PRF = 1.5 MW.
Shot 5: Try increasing the gas to 23 ms duration and tweak Br0 back to 1.75 mT.
Good shot. Similar to shot 4 except that the startup is better.
Shot 6: Good shot. Similar to shot 5. ECDC for 10 minutes between shots 6 and
7.
Shot 7: Good shot except that it disrupted at 1.19 s apparently due to an
impurity injection at 1.16 s. The RF antenna at D port appears to be lighting
up on the wide angle camera view just before the disruption. Continue ECDC
between shots in deuterium.
Shot 8: Good shot. Ramped all the way down. Got EDA H-mode from 0.73 - 1.3
s.
Shot 9: Increase nl04 to 1 x 10^20 m^-2. Good shot. EDA 0.74 - 1.38 s.
Shot 10: Copied TF waveform from 1001220016 and reduced nl04 to 9 x 10^19 m^-2.
Fizzle!
Computer hang in INIT for shot 11. Stuart Sherman is looking into it in the
absence of Tom and Josh.
shot 12: Wolfe taking over from Snipes as Physop while he
gives a presentation a quarterly review.
plasma full length, loses eda at about 1.2sec when d-port
faults momentarily.
It does seem to be peaking up.
Shot 13: raise nl4 to 1.0e20; RF will fire earlier;
#12 had a late breakdown, raise the fill to 23msec
and ef4 from -1270 -> -1280
fizzled. Too many tweaks
pressure was very high .105; the beam moved to .5sec,
and I moved the prepuff the wrong way.
Shot 14: drop prepuff to 19msec, try again (leave ef4 at -1280 for now)
plasma, full length, H->L at .843 and again at 1.098 and 1.32
It's not eda-ish enough, high Prad is killing it.

next shot: copy RXU,ZXU from 1001220016, which seems to have been higher
triang.
Shot 15: copy RXU,ZXU from 1001220016, which seems to have been higher triang.
RXU now -.02, ZXU now +.04
Snipes taking over once again.
Shot 15: Fizzle!
Shot 16: Decrease EF4 current back to -1290 A and take 1 ms off of the prepuff
to 17 ms duration. For some reason, the gas pressure was substantially larger
at breakdown on shot 15 than in previous shots. Good shot. Multiple EDA
H-modes.
Shot 17: Good shot. Multiple short H-modes due to RF tripping.
Shot 18: Reduce nl04 to 7 x 10^19 m^-2. Good shot. Multiple H-modes.


Session Leader Comments

Physics Operator Comments
Jul 16 2001 08:16:41:360AMJoseph SnipesRun Plan and ENGINEERING SETUP FOR Monday 1010716

MP289A Double Barrier
SL: Rice
PO: Snipes

ECDC in D2 over the weekend with a 60 C bake stopping at 8:00 am

RUN BEGINS AT 10:00 AND ENDS AT 5:00

Power systems the same as for shot 1010713022

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 6 psi He Hybrid DISABLED(PG5)
Enable the following gate valves, assuming no vacuum problems:
ECE, DNB, VUV

RF STATUS:

XMTR 1 AND 2, RUN-ON STARTED AT 8:00 AM
XMTR 3 AND 4, RUN-ON STARTED AT 8:00 AM

RUN PLAN:

RF antenna conditioning for the first couple of hours to determine
if the RF is far enough along to begin MP289A ITB studies.
In the event of RF problems, fall back MP's include:
MP259 MSE calibration (beam into gas with field) Yuh
MP137 L-H-L transitions Hubbard
MP233 Density Limits [g],laBombard
Piggybacking by MP281 Edge Turbulence Imaging is expected on any
of the above except MP259.

Jul 16 2001 08:17:46:470AMJoseph Snipesrtnode -- data loaded, A matrix responds
rtnode -- data loaded, M matrix responds
rtnode -- data loaded, PID matrix responds
RT_NODE Done
16-JUL-2001 08:07:10.29 doing TCL command TYPE *************** END COL
*************** END COLDSTART ******************
Successful coldstart.
Jul 16 2001 10:49:20:830AMJoseph SnipesRun Delayed until 11:15 due to RF maintenance.
Jul 16 2001 11:17:03:057AM1010716001Joseph SnipesShot 1: Start from 1010713022 with no changes to see how well the RF performs.
Fizzle!
Jul 16 2001 11:31:37:647AM1010716002Joseph SnipesShot 2: Raised Br0 by 0.5 mT to 0.5 mT and increased EF4 current from -1290 A
to -1270 A. Try again. Wrong way on Br0. My mistake. Fizzle again!
Jul 16 2001 11:51:36:107AM1010716003Joseph SnipesShot 2: Raised Br0 by 1 mT to 1.5 mT. Fizzle again!
Jul 16 2001 12:04:33:240PM1010716004Joseph SnipesShot 4: Raise Br0 by another 0.5 mT to 2 mT and decrease prepuff from 24 ms
to 21 ms duration. Good shot. Full length plasma with EDA H-mode from 1.07 s
to 1.55 s. PRF = 1.5 MW.
Jul 16 2001 12:19:21:613PM1010716005Joseph SnipesShot 5: Try increasing the gas to 23 ms duration and tweak Br0 back to 1.75 mT.
Good shot. Similar to shot 4 except that the startup is better.
Jul 16 2001 01:12:44:137PM1010716006Joseph SnipesShot 6: Good shot. Similar to shot 5. ECDC for 10 minutes between shots 6 and
7.
Jul 16 2001 01:13:02:687PM1010716007Joseph SnipesShot 7: Good shot except that it disrupted at 1.19 s apparently due to an
impurity injection at 1.16 s. The RF antenna at D port appears to be lighting
up on the wide angle camera view just before the disruption. Continue ECDC
between shots in deuterium.
Jul 16 2001 01:28:39:527PM1010716008Joseph SnipesShot 8: Good shot. Ramped all the way down. Got EDA H-mode from 0.73 - 1.3 s.
Jul 16 2001 01:50:34:350PM1010716009Joseph SnipesShot 9: Increase nl04 to 1 x 10^20 m^-2. Good shot. EDA 0.74 - 1.38 s.
Jul 16 2001 02:09:25:870PM1010716010Joseph SnipesShot 10: Copied TF waveform from 1001220016 and reduced nl04 to 9 x 10^19 m^-2.
Fizzle!
Jul 16 2001 02:30:10:820PM1010716011Joseph SnipesComputer hang in INIT for shot 11. Stuart Sherman is looking into it in the
absence of Tom and Josh.
Jul 16 2001 02:48:39:260PM1010716012Joseph Snipesshot 12: Wolfe taking over from Snipes as Physop while he
gives a presentation a quarterly review.
plasma full length, loses eda at about 1.2sec when d-port
faults momentarily.
It does seem to be peaking up.
Jul 16 2001 03:15:25:873PM1010716013Steve WolfeShot 13: raise nl4 to 1.0e20; RF will fire earlier;
#12 had a late breakdown, raise the fill to 23msec
and ef4 from -1270 -> -1280
fizzled. Too many tweaks
pressure was very high .105; the beam moved to .5sec,
and I moved the prepuff the wrong way.
Jul 16 2001 03:32:02:077PM1010716014Steve WolfeShot 14: drop prepuff to 19msec, try again (leave ef4 at -1280 for now)
plasma, full length, H->L at .843 and again at 1.098 and 1.32
It's not eda-ish enough, high Prad is killing it.

next shot: copy RXU,ZXU from 1001220016, which seems to have been higher triang.

Jul 16 2001 03:37:19:273PM1010716015Steve WolfeShot 15: copy RXU,ZXU from 1001220016, which seems to have been higher triang.
RXU now -.02, ZXU now +.04

Jul 16 2001 03:49:40:063PM1010716015Joseph SnipesSnipes taking over once again.
Shot 15: Fizzle!
Jul 16 2001 04:09:53:837PM1010716016Joseph SnipesShot 16: Decrease EF4 current back to -1290 A and take 1 ms off of the prepuff
to 17 ms duration. For some reason, the gas pressure was substantially larger
at breakdown on shot 15 than in previous shots. Good shot. Multiple EDA
H-modes.
Jul 16 2001 04:47:49:143PM1010716017Joseph SnipesShot 17: Good shot. Multiple short H-modes due to RF tripping.
Jul 16 2001 05:08:34:730PM1010716018Joseph SnipesShot 18: Reduce nl04 to 7 x 10^19 m^-2. Good shot. Multiple H-modes.
Jul 16 2001 05:23:15:430PM1010716018Joseph SnipesSummary: The machine ran reasonably well, although there were a half dozen
fizzles due to difficulties in tuning up the fields and gas, particularly the
gas at breakdown. The RF ran so-so with about 2 MW typically, sometimes
reasonably steady, but sometimes tripping. The ITB's were not generated under
these rather non-stationary multiple H-mode conditions. So, the MP will
continue tomorrow. The H/(H+D) ratio was not too bad, starting at 4 - 5 %, but
it did climb some during the longer RF pulses to 10% or so. Between shot ECDC
in D2 helped, but some care needs to be taken to allow the gas to pump out
before going to INIT.
1 0.000 0.032 2 0.000 0.037
3 0.000 0.045 4 1.948 0.792
5 1.944 0.792 6 1.911 0.789
7 1.194 0.805 8 1.919 0.802
9 1.892 0.797 10 0.000 0.032
11 0.000 0.003 12 1.871 0.789
13 0.000 0.029 14 1.848 0.797
15 0.000 0.032 16 1.862 0.797
17 1.892 0.802 18 1.918 0.805

Finished summary for 1010716 Total of 18 shots.
18 shots. 11 plasmas. 6 fizzles. 1 test

Engineering Operator Comments
ShotTimeTypeStatusComment
111:13:11:050AMPlasmaOk
211:26:32:137AMPlasmaOk
311:41:43:900AMPlasmaOk
411:57:08:570AMPlasmaOk
512:14:47:730PMPlasmaOk
612:32:31:107PMPlasmaOk
712:57:05:780PMPlasmaOk
801:20:41:793PMPlasmaOk
901:42:45:243PMPlasmaOk
1002:05:12:753PMPlasmaOk
1102:17:52:637PMPlasmaBadno power, shot action monitor hung up.
1202:40:38:980PMPlasmaOk
1303:07:29:717PMPlasmaOk
1403:20:28:007PMPlasmaOk
1503:47:15:920PMPlasmaOk
1604:07:16:520PMPlasmaOk
1704:35:56:200PMPlasmaOk
1805:00:34:857PMPlasmaOk