Alcator C-Mod Run 1050426 Information

Back to runs

Miniproposals
Miniproposal:417
Date Filed: 2/24/2005
Title:Plasma performance, boronization and ICRF heating effectiveness with high-Z antenna guards and all-m
First Author:Yijun Lin
Session Leader:Yijun Lin (shots 1-23)

Operators
Session leader(s):Yijun Lin
Physics operator(s):
Engineering operator(s):Bill Cochran,Bill Byford,Bill Parkin

Engineering Operator Run Comment
MP#417, Post 2nd-Boronization

Session Leader Plans
Entered: Apr 26 2005 09:35:48:067AM
Author: Yijun Lin
SL plan: 1050426
MP417, post 2nd-boronization

Run starts at 10:45 am.

Fiducial plasma at 1 MA (load 1050422003)

Starts with post-boronization recovery. RF conditioning until clean 3 MW available.
RF waveform: [0.7-0.85] sec, 0.6 MW
[0.85, 1.2] sec, 0.6 ramping up to 2 MW
[1.2, 1.5] sec, constant 3 MW

1 shot: same RF waveform. Gate valves closed. (fiducial discharge)
3 shots: Performance at RF power scan. RF power at 1, 2, 3, 4 MW.
(1 MW and 2 MW can be done in the same shot)
7 shots: Performance vs density. Density scan
nl04 = 0.8, 0.9, 1.0, 1.1, 1.2, 1.3, and 1.4e20 m^-2
at 3 MW RF power.

2 shots: 0.8 MA, reload 1050421016. Density scan 0.8 and 1.0e20 m^2

2 shots: puff D2 in H-mode (same as in shot 1050422026). Choose the nl04 with the best performance.
1 shot: puff D2 in L-mode (RF power below L-H threshold)
2 shots: puff N2 in divertor (same as shot 1050422025, 11 PSI in Ninja. puff 0.2 sec and 0.4 sec).
1 shot: puff N2 in L-mode (RF power below L-H threshold)

If both D2 and N2 puff show enhancement on plasma performance, then
2 shot: puff both N2 and D2.

2 shots: 1.2 MA, (reload shot 1050420032)
Density scan 1.2 and 1.4e20 m^2, 3MW.
1 shot: 1.2 MA, 4 MW.

Physics Operators Plans
Entered: Apr 25 2005 06:08:17:103PM
Author: Robert Granetz
Engineering setup for Tuesday, 26 Apr 2005

MP 417: Performance comparisons (post 2nd boronization)

Session leader: Y. Lin
Physics operator: R. Granetz

Boronize overnight, followed by 2+ hours of ECDC in D2; bake at 60 C.

Run begins at 10:45 and ends at 17:00.

Power systems as on 1050422003 (1 MA, 5.4 T fiducial plasma)

A-coil configuration: normal [+Dtop -Dbot -Jtop +Jbot] and enabled.

Gas Setup:
fill B-Top with 6 psi D2 Hybrid enabled (PG4)
fill B-side lower with 2 psi Ar Hybrid enabled (PG1)
leave B-side upper with whatever Hybrid disabled
fill B-main (C-side) with 40 psi D2 Hybrid enabled (PG3)

fill NINJA with 8 psi N2 Leave disabled to begin with

Torvac setup: machine gate valves to remain open during and after shot. (I
need to reconfirm this in the morning before the run begins.)

Enable the following gate valves, assuming no vacuum problems:
ECE, VUV, Z-bolo shutters

Necessary diagnostics: Core/confinement incl. bolometry, pedestal profiles,
H/D, boron and molybdenum monitoring

-------------------------------------------------------------------------------
ICRF Setup: All transmitters in run on at 10:15.

-------------------------------------------------------------------------------
Run plan: Start with shot 1050422003 (1 MA, 5.4 T fiducial plasma)
(1) Post-boronization recovery and ICRF conditioning
(2) RF power ramp (H-mode threshold)
(3) RF power scan (2, 3, 4 MW)
(4) Density scan at Prf = 3 MW
Some D2 and N2 puffing will be done in part (4)
(5) 0.8 MA, two densities, 3 MW
(6) 1.2 MA, two densities, 3 MW
(7) 1.2 MA, 4 MW

Session Leader Summaries
Entered: Apr 27 2005 03:30:49:440PM
Author: Yijun Lin
SL summary:

--------------
We had a new record C-Mod shot today, 1050426022:

Wtot (efit) = 0.250 MJ
Volume = .918 m3
Averaged P = 1.80 atmosphere (World tokamak record?)
2*P_e(0) [Thomson scattering] = 5.1 Atmosphere
T_e(0) ~ 4.4 keV
n_e(0) ~ 4.3e20 m^-3
I_p = 1.06 MA
D-D fusion reaction rate (2*neutron rate) ~ 5e14/second (but needs checking; a lot of the neutron signals are saturated)
P_RF = 5 MW
beta_N ~ 1.73
Z_eff ~ 1.4
-------------------------

The Mo level and Prad in this run are much lower than that in 1050420. The boronization was done over all the outer wall and antenna structure. H/D level is at 3-4% all day.

Shot 1 got H-mode with only 0.4 MW RF power.

At this clean machine condition, puffing argon seems to have significant effect on performance (shot 9 and 10). The H-mode becomes more ELM-free like and the stored energy is lower.

Puffing D2 in H-mode also keeps the stored energy to stay constant. Shot 16 without puff, shot 22 with puff.

N2 was puffed on shot 23. The first H-mode with N2 went to ELM-free like. It is too complicated to tell whether N2 helped.
-------------------------
An alternator problem terminated the run (bearing vibration alarm tripped).



Physics Operator Summaries
Entered: Apr 27 2005 03:15:47:753PM
Author: Robert Granetz
Physop summary for Tuesday 26 April 2005:

MP 417: Plasma performance, boronization, ICRF with all metal

The machine ran well today, the first day after boronization (and helium
ECDC and D2 ECDC). We achieved record stored energy (1050426022 had 250
kJ) with 5 MW of ICRF. We were basically running a 1 MA, 5.4 T, lower
single null fiducial all day, while varying RF power, gate valve status,
and D2 and N2 gas puffs. H/(H+D) was low all day (3-4%), as was Zeff
(1-1.3). It looks like this boronization worked much better than the
previous one. (This boronization went all the way out to the outer wall.)
Keeping the gate valves closed during and after the shots seemed to result
in increased chance of fizzles. Also, it was pretty clear that the
confinement was significantly degraded by argon puffing on the two shots
that we tried it (09 and 10).

Note that the run started late due to a visitation by a VIP, and extended
discharge cleaning after the boronization.

Also, shot 20 was a no-power shot cycle because an alternator alarm occurred due
to excessive bearing vibration. This same problem prevented us from taking the
last shot of the day

Scorecard: 16 plasmas
5 fizzles
1 dud
1 tests or no-power shot cycles
0 beam-into-gas calibration shots with B-field(s)
----------
23 total shot cycles

Session Leader Comments
Apr 26 2005 11:15:08:003AM1050426001Yijun Linshot 1: (post-boronization recovery) (load 1050422003)
Request: 1 MA, 5.4 T, nl = 0.9e20 m^-2.
RF power ramping up from 0.6 MW to 3 MW.
Gate valves closed for 5 minutes for wall pumping study
Result: Plasma. H-mode,
H mode transition at 0.4 MW RF power (really low).

No power from D nor E because of a CAMAC problem.
No cell data for all antennas because of a CPCI problem.

98 kJ at 0.7 MW power. H/D 2-3%

Next: repeat. hopefully with all antenna power.

Apr 26 2005 11:42:47:220AM1050426002Yijun Linfizzle
Apr 26 2005 12:05:43:987PM1050426003Yijun Linshot 3: (RF conditioning)
Request: 1 MA, 5.4 T, nl = 0.9e20 m^-2.
RF power ramping up from 0.6 MW to 3 MW.
Gate valves closed for 5 minutes for wall pumping study
Result: plasma. H-mode. Excellent shot.
L-H transition at 0.8 MW Prf
W = 139 kJ at Prf = 2 MW at 1.19 sec. Pradmain = 0.4 MW
W = 115 kJ at Prf = 1.5 MW at 1.3 sec. Prad main = 0.9 MW
W = 148 kJ at Prf = 3 MW at 1.22 sec. Prad main = 1.8 MW (A lot more radiation here).
H/D 3.6% (It is higher than shot 1)

Next repeat.
Apr 26 2005 12:52:57:580PM1050426004Yijun Linshot 4: (RF conditioning)
Request: 1 MA, 5.4 T, nl = 0.9e20 m^-2.
RF power ramping up from 0.6 MW to 3 MW.
Gate valves are open
Result: plasma. H-mode. Excellent shot.
L-H transition at 0.8 MW Prf
H/D 3.6% (It is higher than shot 1)

Next repeat.
Apr 26 2005 12:52:44:127PM1050426005Yijun Linshot 5: (RF conditioning)
Request: 1 MA, 5.4 T, nl = 0.9e20 m^-2.
RF power ramping up from 0.6 MW to 3 MW.
Gate valves are open
Result: plasma. H-mode.
L-H transition at 0.8 MW Prf
H/D 3.%
W 153 kJ at 3 MW at 1.4 sec. Two injections at 1.06 and 1.2 sec.

Next Raise RF power to 4 MW late in the shot for further conditioning.
Apr 26 2005 12:56:20:190PM1050426006Yijun Linshot 6: (RF conditioning)
Request: 1 MA, 5.4 T, nl = 0.9e20 m^-2.
RF power ramping up from 0.6 MW to 2 MW, then to 4 MW
Result: plasma. H-mode. J-port was not able to run due to high neutral pressure.
L-H transition at 0.5 MW Prf
H/D 3.%
W 157 kJ at 2 MW at 1.4 sec. Prad = 0.5 MW. H89 = 1.7 and rising.

Next repeat.
Apr 26 2005 01:08:49:533PM1050426007Yijun Linshot 7: (RF conditioning)
Request: 1 MA, 5.4 T, nl = 0.9e20 m^-2.
RF power ramping up from 0.6 MW to 2 MW, then to 4 MW
Result: plasma. H-mode.
L-H transition at 0.7 MW Prf
H/D 3.5%
W 192 kJ at 4 MW at 1.4 sec. H89 = 1.3-1.6 for whole H-mode.

Next RF 1 MW and 2 MW.
Apr 26 2005 01:12:05:893PM1050426008Yijun Linfizzle
Apr 26 2005 01:33:48:987PM1050426009Yijun Linshot 9: (RF power scan)
Request: 1 MA, 5.4 T, nl = 0.9e20 m^-2.
RF power 1 MW and 2 MW
Result: plasma. H-mode.
H/D 3.5%
got H-mode at 1 MW, but not at 2 MW (How come?)
W at 98 kJ at 1 MW.
Next swap the order of 1 MW and 2 MW.

Apr 26 2005 01:45:22:470PM1050426010Yijun Linshot 10: (RF power scan)
Request: 1 MA, 5.4 T, nl = 0.9e20 m^-2.
RF power 2 MW and 1 MW
Result: plasma. H-mode.
H/D ~3%
W at 110 kJ at 2 MW.
It took a long time to get into H-mode and it is ELM-free like

(Ar was puffed in shot 9 and 10. Is it the cause?

next: 2 MW and 3 MW. No Ar puff.


Apr 26 2005 02:16:54:300PM1050426011Yijun Linshot 11: (RF power scan)
Request: 1 MA, 5.4 T, nl = 0.9e20 m^-2.
RF power 2 MW and 3 MW (got 2 and 1.6)
Result: plasma. H-mode.
H/D ~3%
W at 140 kJ at 2 MW.
Now the H-mode is more EDA like.
The 2nd RF pulse only goes to 1.6 MW, No H-mode
(why? density gradient not relaxed to the same condition?)

Comparing shot 11 and 10, it seems that Ar does matter and the plasma
behavior is very very sensitive to it.

next: repeat. No Ar puff. Separate the two RF pulse by 200 ms instead of 100 ms.


Apr 26 2005 02:18:02:067PM1050426012Yijun Linshot 12: (RF power scan)
Request: 1 MA, 5.4 T, nl = 0.9e20 m^-2.
RF power 2 MW and 3 MW
Result: plasma. H-mode.
H/D ~3%
W at 140 kJ at 2 MW.
173 kJ at 3 MW.

next: 3 MW and 4 MW. No Ar puff. Gate valves closed.

Apr 26 2005 02:45:19:050PM1050426014Yijun Linshot 14: (RF power scan)
Request: 1 MA, 5.4 T, nl = 0.9e20 m^-2.
RF power 3 MW and 4 MW
Result: plasma. H-mode.
H/D ~3%
W at 173 kJ at 3 MW.
226 kJ at 4 MW.
(Since there is not a lot time left, i would like to start D2/N2 puff)
Next: constant 3 MW with a jump to 4 MW in the end of RF pulse.
Same plasma.
Apr 26 2005 02:47:58:237PM1050426015Yijun Linfizzle
Apr 26 2005 03:17:32:330PM1050426017Yijun Lindud
Apr 26 2005 03:37:34:670PM1050426018Yijun Linshot 18:
(D2 puff at 60V on PG3)
Request: 1 MA, 5.4 T, nl = 0.9e20 m^-2.
RF power 3 MW, 4 MW and 5 MW.
Result: plasma. 2 H-modes
H/D 3.5-4%
Wmhd at 165 kJ at 3 MW. (A big injection at 0.9 sec and killed the first H-mode)
220 kJ at 4 MW. Prad main at 1 MW (significantly lower than shot 16)
(Was the D2 puff that saved the plasma and pushed it back to good performance?)

Next: repeat

Apr 26 2005 03:42:29:670PM1050426019Yijun Linfizzle
Apr 26 2005 04:00:58:700PM1050426020Yijun Linshot 20: No power shot. Alternator problem.
Apr 26 2005 04:36:27:997PM1050426021Yijun Linshot 21:
(D2 puff at 60V on PG3)
Request: 1 MA, 5.4 T, nl = 0.9e20 m^-2.
RF power 3 MW, 4 MW and 5 MW.
Result: plasma. H-mode.
H/D ~4%
Wmhd at 180 kJ at 3 MW. 1 MW Prad_main
202 kJ at 4 MW. 1-1.4 MW Prad_main
238 kJ at 5.1 MW (record Wmhd in C-Mod)
Wmhd was rising all the way in the 2nd H-mode. Possibly an injection killed the
first H-mode.

Apr 26 2005 04:46:35:370PM1050426022Yijun Linshot 22, repeat.
(D2 puff at 60V on PG3)
Request: 1 MA, 5.4 T, nl = 0.9e20 m^-2.
RF power 3 MW, 4 MW and 5 MW.
Result: plasma. H-mode.
H/D ~4%
Wmhd at 172 kJ at 3 MW. 1 MW Prad_main
220 kJ at 4 MW. 1-1.4 MW Prad_main, Prad_main 1.4 MW.
249.7 kJ at 5. MW (another record Wmhd in C-Mod) Prad_main 1.5 MW.
A perfect shot.

Next: Do N2 puff. (starting from 0.65 sec for 300 ms)


Physics Operator Comments
Apr 26 2005 10:48:42:470AMRobert GranetzGV1 will be disabled so that it can not open until mass 18 goes down.
(Due to change of RGA filament last night and subsequent baking of stack.)
Apr 26 2005 10:57:24:893AMRobert GranetzDate: Tue, 26 Apr 2005 10:24:00 -0400
From: Amanda Hubbard
To: Robert S. Granetz , Yijun Lin
Subject: ECE today

Bob, Yijun,
I have to go to a medical appt shortly. Just to let you know, there is some
uncertainty about the state of GPC; it is low on helium and I can't fill it.
So, it may or may not give signals.
GPC2 and Michelson should be OK.
back about noon,
Amanda
Apr 26 2005 11:18:00:283AM1050426001Robert GranetzPlasma. Good shot. No problems with boronization recovery, apparently.
Due to some problem with the RF camac control signals, D and E didn't fire.
J fired up to 1 MW. There was an EDA H-mode, but Wpla didn't even reach 100 kJ.
H/D=2-3%. H-mode threshold was an incredibly low 0.4 MW !

Gate valves were kept closed for 5 minutes after the shot (after much discussion
among Bruce and Yijun this morning).

Cell access required after the shot to fix RF CPCI.

Next shot: no PCS changes. Gate valves will remain closed again.
Apr 26 2005 11:42:33:597AM1050426002Robert GranetzFizzle.

Next shot: decrease pre-fill puff by 2 ms.
Apr 26 2005 12:15:51:317PM1050426003Robert GranetzPlasma. Good shot. Prf peaks at 2.9 MW briefly. L/H transition is around 0.7 MW.
There are a bunch of impurity injections (similar to shot 01).
H/(H+D) = 3-3.5%

Gate valve remained closed after this shot.

Next shot: no PCS changes. Gate valve will be OPEN after the shot.
Apr 26 2005 12:37:23:567PM1050426004Robert GranetzPlasma. Good shot. Max Prf = approx 2 MW. EDA H-mode, threshold Prf is 0.7 MW (must add
ohmic, of course). H/(H+D)=3.5%. Another big impurity injection at 1 s.

Gate valve was open, and will remain open until further notice.

Next shot: no PCS changes.
Apr 26 2005 12:41:17:580PM1050426005Robert GranetzPlasma. Similar to previous shots today. Jim Terry reports that molybdenum in the plasma
is down by an order of magnitude compared to last week. Prf peaks at 3 MW briefly. H-factor
reported to reach 1.6 at that time. Two large impurity injections again.

Gate valves are open.

Next shot: no PCS changes. Prf will be increased to 4 MW.
Apr 26 2005 12:55:07:190PM1050426006Robert GranetzPlasma. Good shot. J-port faulted so max Prf=2 MW. Max Wpla > 150 kJ.
H-factor is 1.7 and rising until a late impurity injection.
H/(H+D)=3%. John Rice reports "no moly".

Gate valve open.

Next shot: no PCS changes.
Apr 26 2005 01:09:03:160PM1050426007Robert GranetzPlasma. Good shot. Max Prf=4 MW. Max Wpla > 190 kJ. H/(H+D)=3%. Zeff=1.0-1.1

Next shot: start shot-to-shot RF power scan. No PCS changes.
Apr 26 2005 01:10:46:207PM1050426007Robert GranetzBeautiful miniature exploding fireworks shell on LH video view at t=0.211 s (frame 7).
Apr 26 2005 01:17:46:910PM1050426008Robert GranetzFizzle.

Next shot: reduce pre-fill puff by 2 ms. Turn on argon with 50 ms puff at t=0.3 s.
Apr 26 2005 01:34:09:003PM1050426009Robert GranetzPlasma. Good shot. Strange H-mode behavior, or lack thereof. Max Prf=2 MW, but no H-mode
at that time. There was an earlier ELM-free H-mode when Prf=1 MW.

Next shot: no PCS changes. Continue RF power scan.
Apr 26 2005 01:45:18:550PM1050426010Robert GranetzPlasma. Good shot. Another shot with strange H-mode behavior. Prf=2 MW at first, then 1 MW.
Plasma takes a long time to transition to an (ELM-free) H-mode. Ditto with the 2nd RF pulse.

Next shot: disable the argon puff. No PCS changes.
Apr 26 2005 02:04:57:207PM1050426011Robert GranetzPlasma. Good shot. No argon puffed this shot. Nice EDA on the first RF pulse (2 MW), but
no H-mode on the 2nd pulse (1.6 MW). H/(H+D)=3%

Next shot: no PCS changes. No argon.
Apr 26 2005 02:13:52:970PM1050426012Robert GranetzPlasma. Good shot. Prf=2 MW then 3 MW. Plasma stays in EDA H-mode even through the intervening
ohmic period. Max Wpla > 170 kJ. H/(H+D)=3%.

Next shot: gate valve will remain closed for 5 minutes after the shot.
Apr 26 2005 02:21:42:643PM1050426013Robert GranetzFizzle.

Next shot: reduce pre-fill by 1 ms. Keep the gate valves closed.
Apr 26 2005 02:42:38:080PM1050426014Robert GranetzPlasma. Good shot. Max Prf=4 MW. Max Wpla = 226 kJ. Large 1/1 oscillations on x-rays and
nl_04 between the two H-mode/RF periods. Max H-factor = 1.9. H/(H+D)=3%.

Next shot: repeat, no changes. Gate valve will remain closed.
Apr 26 2005 02:49:03:707PM1050426015Robert GranetzFizzle. Everything looks very good.

Next shot: keep the gate valve open. No PCS changes.
Apr 26 2005 03:12:31:613PM1050426016Robert GranetzPlasma. Good shot. Prf=4 MW. Wpla=220 kJ. H/(H+D)=3.7%.

Next shot: puff deuterium t=0.7-1.2 s. Gate valve remains open.
Apr 26 2005 03:22:21:970PM1050426017Robert GranetzDud. I don't see why. Gas and fields look fine.

Next shot: add 1 ms to pre-fill. Keep gate valve open.
Apr 26 2005 03:37:35:183PM1050426018Robert GranetzPlasma. Good shot. Max Prf=4 MW. Max Wpla=220 kJ. There was a very big injection at 0.9 s,
but nothing shows up on the video views.

Next shot: repeat without the injection, hopefully. Gate valve will remain open.
Apr 26 2005 03:45:49:793PM1050426019Robert GranetzFizzle. Current didn't rise fast enough so it got squashed into the inboard wall.

Next shot: reduce pre-fill by 1 ms. (I just increased it on the last shot because
of the dud !)
Apr 26 2005 05:25:41:670PM1050426020Robert GranetzNo-power shot cycle. Alternator bearing alarm occurred during CHECK state.
Apr 26 2005 04:32:43:777PM1050426021Robert GranetzPlasma. Good shot. I think it's a record stored energy of 238 kJ. Max Prf=5 MW, briefly.
Breakdown and current rise look great.

Next shot: repeat, including the D2 puff again.

Apr 26 2005 04:46:19:043PM1050426022Robert GranetzPlasma. Good shot. Peak Wpla=250 kJ...another new record. Peak Prf=5.1 MW.
H/(H+D)=3.5-4%. Zeff=1.0-1.4. Moly is starting to come up.

Next shot: turn off D2 puff, turn on N2 NINJA puff.
Apr 26 2005 05:03:06:090PM1050426023Robert GranetzPlasma. Good shot. Wpla=200 kJ. Max Prf=4 MW, except for a very brief excursion to 5 MW.

Next shot:

Next shot cancelled. Alternator bearing alarm when off again.

End of run.

Engineering Operator Comments
ShotTimeTypeStatusComment
110:55:28:627AMPlasmaOk
211:39:14:817AMPlasmaOk
311:54:45:143AMPlasmaOk
412:17:18:020PMPlasmaOk
512:31:03:923PMPlasmaOk
612:43:43:440PMPlasmaOk
712:57:14:970PMPlasmaOk
801:09:49:363PMPlasmaOk
901:22:28:410PMPlasmaOk
1001:35:21:173PMPlasmaOk
1101:48:18:627PMPlasmaOk
1202:05:49:550PMPlasmaOk
1302:18:27:660PMPlasmaOk
1402:31:27:410PMPlasmaOk
1502:45:15:923PMPlasmaOk
1603:00:09:643PMPlasmaOk
1703:15:05:660PMPlasmaOk
1803:28:03:330PMPlasmaOk
1903:40:40:030PMPlasmaOk
2003:53:15:730PMTestBad
2104:22:03:887PMPlasmaOk
2204:34:35:607PMPlasmaOk
2304:48:05:200PMPlasmaOk