| Session Leader Plans |
| Entered: Jul 4 2005 04:17:54:257PM |
| Author: Earl Marmar |
Run Plan for Tuesday, July 5, 2005
MP#417 Evaluation of all-metal walls: between shot boronization
SL: Earl Marmar
PO: Ian Hutchinson
Run BEGINS @ 09:00 and ENDS @ 17:00
No overnight ECDC. Bake at 60 C.
This is will be an unusual setup. In order to boronize between shots, the cell must remain closed throughout the day. The di-borane gas system must be set up to allow between shot boronization. We should plan to be locked up in time for first shot at 9:00 am, without any boronization before the first shot. We will start with fiducial-like plasmas (1MA, 5.3 Tesla, nl_04 target = 1e20, P_RF = 3 MW (from .7 to 1.2 seconds) lower single null diverted. After the first good shot, we will boronize for 10 minutes, using the standard parameters.
The ECDC scan should go from 50 cm to 103 cm, dwelling at 52 cm.
Engineering setup as on shot 1050701002.
A-coil in standard configuration (+Dtop -Dbot -Jtop +Jbot)
C-coil Start=0.3sec, Invert=2.0sec
ICRF in Run-on condition by 8:30 AM
Gas setup:
fill B-top 6psi D2 Hybrid Enabled (PG4)
fill B-side lower 1psi Argon Hybrid Enabled (PG1) (start with 30 msec puff at .3 seconds)
leave B-side Upper alone Hybrid DISABLED (PG2)
fill B-main 40psi D2 Hybrid Enabled (PG3)
Enable: ECE, VUV, Z-bolo shutter for tokamak plasma attempts; these must all be closed during between-shot boronization.
The A-Side TV camera shutter must be CLOSED before the start of the run, and remain closed throughout the day. The wide1 TV view will not be available for this run.
The MSE shutter must be CLOSED before the start of the run, and remain closed throughout the day.
Run Plan:
We will run fiducial-like shots (1 MA, 3 MW RF, 5.3 T, target nl_04 = 1e20, LSN), with something like 10 or 15 minutes of boronization between shots. This will slow the cycle somewhat, as it usually takes about 5 minutes after the shot before ECDC starts. If it looks like we are having positive results, we can consider reducing the amount of time boronizing between shots, to as little as 5 minutes. If we have trouble with startup, or with antenna performance, we might also consider reducing the amount of time boronizing between shots, and/or reduce the outboard extent of the ECDC sweep. If there seems to be little or no effect (radiated power, moly levels, h-factor) after 5 shots, we might extend the boronization to 30 minutes between shots, but that would significantly reduce the total number of plasma attempts. Assuming breakdown and current rise are not problematic, we will not do any post boronization ECDC in helium or deuterium. If we have a fizzle or dud, we will try again without additional boronization prior to the next attempt.
The amount of diborane used during each between-shot boronization period will be monitored and recorded in the logbook.
If there are problems with the interferometer for density feedback, switch to Z-meter feedback, since cell entry will not be available.
Critical diagnostics include the McPherson, Chromex, Bolos, Z-meter, Thomson, hirex, RGA, divertor pressure.
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| Session Leader Summaries |
| Entered: Jul 6 2005 06:48:38:190PM |
| Author: Earl Marmar |
Session leader summary
MP417: all metal walls ...
This run was used to investigate the effects of between-shot boronization, the first time this was tried on C-Mod.
It was a very interesting and quite successful run. Clear effects of as little as 10 minutes of between-shot boronization were seen. Increasing the time to 20 and then 30 minutes (shot 18) showed monotonically increasing improvement (reduction of molybdenum and radiated power, increase of peak and integral neutron rate, increase of peak stored energy). Another interesting result is that the effects of these short boronizations are almost completely gone after 1 shot. The 30 minute boronization did have a small lingering effect on the second shot which followed, with no additional boronization in between. That second shot (19) was slightly better than shot 2 (no boronization), but not as good as shots with 10 minutes of pre-boronization.
The RF ran very reliably at 3 MW throughout the day (after a bit of tuning following shot 1), with very few trips. This greatly facilitated the shot by shot comparisons of the effects of the boronizations.
After the first 2 shots, we started with 10 minutes of boronization prior to shot 3, which fizzled. On shot 4, Wmax increased from 140 to 166 kJ, and the initial rate of increase of radiated power after the H-mode transition (using the 2pi diode signal) was reduced by nearly a factor of 2. A plot of integrated neutron rate (from .7 to 1.2 seconds) vs. the time of boronization before the shot is shown here:
The lowest point with 10 minute preboronization is shot 22. In this case, the ECDC scan was from 44 to 80 cm, dwelling at 52 cm, and this seems to have been the least effective. All the other cases had scans from 50 to 103 cm, dwelling at 52 cm.
The next plot shows the total number of neutrons produced during the RF pulse (0.7 to 1.2 s) as a function of the rate of rise of total radiated power just after the transition into H-mode, using the 2-Pi AXUV diode (multiplied by 2) as the measure of radiated power. Again the correlation is clear.
Table of shots with amounts (minutes) of preboronization, and ECDC scan parameters (min, dwell, max) in cm.
Shot/Time/ECDC
001/0/N.A.
002/0/N.A.
004/10/50, 52, 103
005/10/50, 52, 103
007/10/50, 52, 103
009/20/50, 52, 103
010/0/N.A.
012/20/50, 52, 103
014/20/50, 52, 103
016/10/50, 52, 103
018/30/50, 52, 103
019/0/N.A.
022/10/44, 52, 80
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| Session Leader Comments |
| Jul 5 2005 09:15:06:450AM | 1050705001 | Earl Marmar | fiducial
argon disabled for this shot
several H-modes, many E-port trips
wtot ~ 130 kJ
retune the RF and repeat
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| Jul 5 2005 09:35:40:697AM | 1050705002 | Earl Marmar | repeat
argon on for this shot
better RF (2 short trips on J-port)
3 h-modes; still looking ELM-freeish
WMHD ~ 140 kJ
PRad_main peaks at about 2 MW at each back-transition
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| Jul 5 2005 10:23:04:277AM | 1050705003 | Earl Marmar | 10 minutes of boronization ECDC before this shot
scan 50 to 103 cm, dwell at 52
fizzle
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| Jul 5 2005 10:32:35:573AM | 1050705004 | Earl Marmar | no additional boronization after the fizzle
good plasma
looks a little more EDAish
stored energy peaks at 165 kJ, then rolls over with increasing radiation
H/(H+D) appears a bit lower (.045 vs .055 on shot 2)
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| Jul 5 2005 11:00:48:247AM | 1050705005 | Earl Marmar | 10 minutes boronization ECDC before this shot
scan 50, 52, 103
good plasma
similar to shot 4, Prad ~10% lower at 1.0 seconds
same stored energy (peaks at 166 kJ)
H/(H+D) ~ .045, same as shot 4
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| Jul 5 2005 11:14:44:010AM | 1050705006 | Earl Marmar | boronization ECDC for 10 minutes before this shot
scan 50, 52, 103
fizzle
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| Jul 5 2005 11:36:48:790AM | 1050705007 | Earl Marmar | no additional boronization following the shot 6 fizzle
good plasma
very similar to shot 5
stays in H-mode for the duration of the RF, no RF trips
peak stored energy 168 kJ, then rolls over
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| Jul 5 2005 12:03:44:730PM | 1050705008 | Earl Marmar | 20 minutes boronization ECDC before this shot
scan 50, 52, 103
dud
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| Jul 5 2005 12:43:08:177PM | 1050705009 | Earl Marmar | no additional boronization following dud on shot 8
good plasma
lower Prad at 1.0 s
higher neutron rate, stored energy peaks at 185 kJ
H89 ~ 1.75
H/(H+D) ~ .045
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| Jul 5 2005 12:56:59:647PM | 1050705010 | Earl Marmar | no boronization following plasma on shot 9
good plasma
radiated power is up
Max stored energy 155 kJ
H/(H+D) ~ .04 (a hair lower than shot 9)
This shot seems slightly worse than shot 7. Taken at face value, 20 minutes of boronization "lasts" for ~1 shot (or less).
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| Jul 5 2005 01:54:58:520PM | 1050705011 | Earl Marmar | 20 minutes of boronization ECDC before this shot
scan 50, 52, 103
fizzle
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| Jul 5 2005 01:58:13:460PM | 1050705012 | Earl Marmar | no additional boronization after the fizzle on shot 11
good plasma
very similar to shot 9
compared to shot 10, stored energy is up, radiated power is down (lowest of the day)
no trips, no big injections
max stored energy 175 kJ
H89 ~ 1.67
H/(H+D) ~ 0.042
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| Jul 5 2005 02:04:18:270PM | 1050705013 | Earl Marmar | 20 minutes of boronization ECDC before this shot
scan 50, 52, 103
fizzle
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| Jul 5 2005 02:31:28:257PM | 1050705014 | Earl Marmar | no additional boronization after fizzle on shot 13
good plasma
very similar to shot 12
radiated power reduced even a little further
max stored energy 178 kJ
one short trip on E-port, did not seem to affect things much; could be useful for evaluation of RF absorbed power fraction
H/(H+D) ~ 0.04
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| Jul 5 2005 02:48:38:880PM | 1050705015 | Earl Marmar | 10 minutes of boronization ECDC prior to this shot
fizzle
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| Jul 5 2005 03:12:02:460PM | 1050705016 | Earl Marmar | no additional boronization after the fizzle on shot 15
good plasma
radiated power is up compared to shot 14
max stored energy = 173 kJ, then drooping
small injection at 1.063, but Wmhd was already drooping.
H/(H+D) ~ 0.04
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| Jul 5 2005 03:56:50:147PM | 1050705017 | Earl Marmar | 30 minutes of boronization ECDC before this shot
scan 50, 52, 103
fizzle
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| Jul 5 2005 04:14:02:757PM | 1050705018 | Earl Marmar | no additional boronization following the fizzle on shot 17
good shot
best one of the day
Prad main is below 1 MW for the entire RF pulse, and steady
max stored energy = 186 kJ
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| Jul 5 2005 04:40:42:850PM | 1050705019 | Earl Marmar | no boronization prior to this shot
good plasma
not nearly as good as shot 18
Prad up, moly up
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| Jul 5 2005 04:42:11:443PM | 1050705020 | Earl Marmar | 10 minutes of boronization ECDC before this shot
scan 44, 52, 80 to test effectiveness of scanning to the inner wall
fizzle
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| Jul 5 2005 05:12:51:850PM | 1050705021 | Earl Marmar | no additional boronization after the fizzle on shot 20
fizzle
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| Jul 5 2005 05:20:15:177PM | 1050705022 | Earl Marmar | no additional boronization after the fizzles on shots 20 and 21
good plasma
similar to 19, and several of the shots that also had 10 minutes of preshot boronization (e.g. 7)
max stored energy = 158 kJ
H/(H+D) ~ .038
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| Physics Operator Comments |
| Jul 5 2005 08:43:30:997AM | | Ian Hutchinson | Load from 1050629020.
Import segment 1 from 1050525002.
Touch wire 13, but ensure it gets set back to the same value. Now PCS_compare gives zero differences with 25002.
The main relevant differences in startup were that 1050629020 had EF4=-1285 vs -1310A.
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| Jul 5 2005 09:21:16:980AM | 1050705001 | Ian Hutchinson | Argon is 40ms inherited from the 1050629020, but we start with Ar disabled.
Plasma to rampdown.
Early breakdown. Bounce. Hard xrays. Ratiomatic was off. So we don't know fill pressure.
Fill puff to 25ms from 21ms.
Argon pulse width (PG1) to 30 ms.
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| Jul 5 2005 09:34:15:167AM | 1050705002 | Ian Hutchinson | Plasma to rampdown.
Breakdown at 6.8ms. No hard xrays. 3MW, two brief trips. W=140kJ.
Move to boronization.
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| Jul 5 2005 10:15:58:510AM | 1050705003 | Ian Hutchinson | Ten minutes of boronization. (See Session Leader entries)
Reset fill puff back to 21ms.
Fizzle. Ran at about 3e-6 torus pressure. Got 0.058 on ratiomatic.
Ratiomatic read .013 prior to gas fill puff.
Negligible gas current on that shot.
Lower fill puff to 18 ms.
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| Jul 5 2005 10:42:22:137AM | 1050705004 | Ian Hutchinson | Plasma to rampdown. Goodish H-mode with slower rising radiation, but overwhelming the heating power at 1.1s. 3.2MW, W=165kJ and falling.
Ratiomatic .006 before fill, then .045. Difference: 0.039.
Breakdown at 4.6ms, weak current rise till 14ms.
Fill puff to 14ms.
Boronize.
Hit the button at 3.5e-6 on torus gauge. Pressure at start of countdown 2.8e-6.
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| Jul 5 2005 11:10:15:997AM | 1050705005 | Ian Hutchinson | Plasma to rampdown. Very similar to 4 except slightly lower radiation.
RF trip loses H-mode at 1.1s. W=165kJ.
Ratiomatic 0.015/0.042. Breakdown at 4.8ms; weak initial Ip rise. No hards.
Boronize. No changes. Hit the button at 3.5e-6 (24min). Countdown at
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| Jul 5 2005 11:22:48:667AM | 1050705006 | Ian Hutchinson | Fizzle. Ratiomatic 0.016/0.043. V weak Ip.
Repeat. Entering init at 1.5e-6.
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| Jul 5 2005 12:02:07:243PM | 1050705007 | Ian Hutchinson | Plasma till rampdown. H-mode till RF turns off at 1.2s. Then Ohmic H afterwards.
W=169kJ. Very similar to 5.
Ratiomatic 0.008/0.036. Breakdown at 4.4ms. Weak Ip rise till 11ms.
Boronize for 20 minutes.
Fill puff to 10 ms. Push button at 3.5e-6, 36 minutes. Countdown at 2.8e-6.
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| Jul 5 2005 12:14:05:417PM | 1050705008 | Ian Hutchinson | Dud. Ratiomatic .017/.034
Fill puff to 14ms. Countdown at 1.4e-6.
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| Jul 5 2005 12:27:57:870PM | 1050705009 | Ian Hutchinson | Plasma to rampdown. Noticeable drop in radiation, maybe 30%. Better performance, but RF trip at 1s confuses. W=185kJ.
Ratiomatic 0.009/0.037. No hards.
Repeat without boronization. Fill puff to 16ms. Ratiomatic at countdown: 1.9e-6.
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| Jul 5 2005 01:06:51:833PM | 1050705010 | Ian Hutchinson | Plasma. Noticeably worse radiation than prior shot. W=155kJ.
Ratiomatic 0.01/0.043. Fairly fast Ip rise, small bounce. No hards.
Boronize for 20min.
Fill puff to 13ms. Hit button at 3.5e-6 36 minutes.
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| Jul 5 2005 01:21:13:397PM | 1050705011 | Ian Hutchinson | Fizzle. Breakdown late 10ms.
Fill puff to 16ms.
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| Jul 5 2005 01:47:54:130PM | 1050705012 | Jim Irby | good shot --- prefill was at 16 ms (increased from 13 ms on shot 11)
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| Jul 5 2005 03:11:45:613PM | 1050705012 | Ian Hutchinson | Plasma. Good H-mode. Radiation maintained low. W=175kJ peak, and stays over 150kJ during RF.
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| Jul 5 2005 02:07:31:677PM | 1050705013 | Jim Irby | prefill to 15 ms from 16 ms
boronization for 20 minutes (done at 32:30 into recool)
pushed button at 3.0e-6 Torr (about 42 minutes into recool)
fizzle (prefill to high)
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| Jul 5 2005 02:25:46:240PM | 1050705014 | Jim Irby | prefill back to 16 from 15 ms
entered init at 1.6e-6 Torr
entered pulse at 1.4e-6
plasma into rampdown
radiation reduced compared to shot 9
peak stored energy a little less than shot 9, but stayed up longer
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| Jul 5 2005 02:48:04:613PM | 1050705015 | Jim Irby | prefill from 16 to 12 ms
10 minutes of boronization completed at 19 minutes into recool
entered init at 3.5e-6 Torr
fizzle
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| Jul 5 2005 03:14:06:333PM | 1050705016 | Jim Irby | prefill back to 16 ms from 12 ms
plasma into rampdown
more radiated power than on 9 or 14, less than 12
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| Jul 5 2005 03:46:23:507PM | 1050705016 | Ian Hutchinson | Plasma.
Lower EF3V from 2400 to 2300V at 5ms. This is my attempt to avoid the fizzle.
Fill puff to 13ms. Hit the button at 3.5e-6, 47minutes.
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| Jul 5 2005 03:58:07:473PM | 1050705017 | Ian Hutchinson | Fizzle.
EF3V back to 2400
Fill puff to 16ms.
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| Jul 5 2005 04:13:53:113PM | 1050705018 | Ian Hutchinson | Plasma. This after 30min of boronization is the best yet. W=185kJ. Pradmain just under 1 MW. Also stays in H-mode when the RF turns off.
Slight bounce on startup.
No changes or boronization. Some strange rise on the torus gauge during recool. Hit the button at 3.4e-6. Countdown at 2.6e-6
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| Jul 5 2005 04:33:47:820PM | 1050705019 | Ian Hutchinson | Plasma. Radiation well up before 1s, plus an injection at 1s. W=160kJ, and rolls off. Roughly equivalent to shot 7.
Some hard xrays.
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| Jul 5 2005 04:56:19:910PM | 1050705020 | Ian Hutchinson | EF3V to 2200V at 5ms, (from 2400).
Fill puff stays at 16ms.
Boronize inboard for 10 minutes.
Hit button at 3.5e-6. Countdown at 2.8e-6.
Fizzle.
EF3V to 2400V. (no other changes).
Hit button at 1.5e-6. Countdown at
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| Jul 5 2005 05:08:12:537PM | 1050705021 | Ian Hutchinson | Fizzle. Big bounce on the outside.
Fill puff to 20ms.
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| Jul 5 2005 05:13:17:240PM | 1050705022 | Ian Hutchinson | Plasma. W=160kJ and falling. Pradmain up to 1.7MW. Some hard xrays. Similar to shot 7.
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