Alcator C-Mod Run 1050818 Information

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Miniproposals
Miniproposal:389
Date Filed: 2/5/2004
Title:CNPA Testing and Calibration
First Author:Vincent Tang
Session Leader:Vincent Tang (shots 1-17)
Miniproposal:430
Date Filed: 7/26/2005
Title:Localization of the effect of boronization
First Author:Bruce Lipschultz
Session Leader:Bruce Lipschultz (shots 18-26)

Operators
Session leader(s):Vincent Tang,Bruce Lipschultz
Physics operator(s):Earl Marmar
Engineering operator(s):Andy Pfeiffer,Ed Fitzgerald,Bill Parkin

Engineering Operator Run Comment
MP #389 -- CNPA testing and calibration Session leader: V. Tang MP #380

Session Leader Plans
Entered: Aug 17 2005 12:00:45:183PM
Author: Vincent Tang
Revised Run Plan for 1050818 with J-Port as dipole:
The main goal today is to run a set of inner wall limited plasmas similar to 1050802001 except with D(H) only (No He3) and BT=5.2T. Minimize hard x-rays if possible. Density, current, and power will be scanned. These plasmas will furnish important baseline fast ion data for the multi-channel CNPA system.

A 600 and 800kA density scan from nel_4=0.4-0.8e20/m2 with 2 flat-top RF segments from 0.5-.95s and 1.05 to 1.5s is needed. This should take ~10 good shots. The parameters are (roughly):

shot Nel4 Field Current Eport Jport Eport Jport
1 0.4 5.2 600 0 1.25 1.25 1.25
2 0.4 5.2 800 0 1.25 1.25 1.25
3 0.6 5.2 600 0 1.25 1.25 1.25
4 0.6 5.2 800 0 1.25 1.25 1.25
5 0.8 5.2 600 0 1.25 1.25 1.25
6 0.8 5.2 800 0 1.25 1.25 1.25

RF powers might have to be changed if there are faults. Depending on how well J and E-port are running we might do a few more of these baseline shots. Cell access to fine-tune C-Port aperture might be required. If the DNB is working, fire the beam at t=1.15s. Also, a beam-into-gas shot before the run to give the F-Port Top CNPA system some more calibration data should be done.

If there is more time:
A: (2 Shots)See if there is any noticeable difference between power delivered from E-Port and J-Port. Try to keep the resonance at the same place by varying BT.

B: (2-3 Shots)Change or eliminate sawteeth period while maintaining core plasma parameters.

C : (2-3 Shots) Re-do some of the ~1MW shots but LSN to see if thereā??s any difference between inner-wall limited and LSN for the CNPA.

Total: Plan for ~10 shots to do the core plan, and hope to at least get extra credit A and B.

Entered: Aug 17 2005 04:28:42:307PM
Author: Bruce Lipschultz
MP430 - 'Optimization of between shot boronization'

SL - BLip
PO - E. Marmar

NINJA setup to 10 PSI D2

1) 1 shot gate valves closed 1 MA - a la 1050705018 (nl04=1.05), RF pulse max power (0.7 - 1.5s)

2) set up for boronization (45 minutes)

3) boronize 20 minutes 50% duty cycle 50/52/103 cm

4) Shot at 1 MA full RF power to evaluate. RF pulse 0.7 - 1.5s. Plasma like 1050705018 (nl04=1.05)

5) repeat shot if needed to see if boronization worn off.

6) boronize 20 minutes 100% duty cycle 50/52/103 cm

7) Shot at 1 MA full RF power to evaluate. RF pulse 0.7 - 1.5s. Plasma like 1050705018

8) repeat shot if needed to see if boronization is worn off.

9) If time permits then boronize 15 minutes 100% duty cycle 78/86/103 cm

10) shot to evaluate


Physics Operators Plans
Entered: Aug 17 2005 03:45:11:167PM
Author: Earl Marmar
Engineering setup for Thursday, Aug 18, 2005

MP #389 -- CNPA testing and calibration
Session leader: V. Tang

and

MP #380 -- Between-shot boronization
Session leader: B. Lipschultz

Physics operator: E. Marmar

Overnight ECDC, D2, P=2e-4 torr gauge, and bake at 60 C.

*** NOTE: Set up for between-shot boronization***
but do not open the diborane bottle for the beginning of the run.
Between-shot boronization will be used for the second half of the run.


Run begins at 09:00 and ends at 17:00.

Power systems as on 1050802001 (0.6 MA, 5.2 T, inner wall limited, kappa=1.3)

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 1 psi Ar plus 1 psi neon Hybrid DISABLED (PG1)
leave B-side upper as is He3 Hybrid DISABLED (PG2)
fill B-main (C-side) with 40 psi D2 Hybrid enabled (PG3)
No NINJA

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



-------------------------------------------------------------------------------
ICRF Setup: RF in run-on by 08:30, ready to go on first shot (J-4 running as dipole, 78 MHz; E at 80 MHz)

-------------------------------------------------------------------------------
Run plan: See the session leaders' detailed postings.

Session Leader Summaries
Entered: Aug 22 2005 04:51:36:970PM
Author: Bruce Lipschultz
MP430 - 'optimization of between-shot boronization'

SL - B. Lipschultz
PO - E. Marmar

We did verify that the 100% duty cycle was better although it was not a strong effect. We did verify that we could reach reasonable stored energies even without 3 MW of RF. We did verify that going back to 80 MHz on all antennas was better than with 50MHz. We did verify that 70 cm center for the boronization scan was good.

Injections were very bad today hampering the work being tried. We do not know the reason other than potentially that limiter shots and disruptions occured earlier.

We took over the run around 1:30 and proceeded to get a background shot - shots 18-20.

We then took the time to get the diborane valve open and boronize the machine and proceed with the plan.

The initial comparison was between 50 cm boronization scans (50 cm start/52 cm pause/103 cm end) of 50% and 100% duty cycle. The latter did slightly better for prad_diodex3 (180 vs 310 kW), dPrad/dt (2.6 vs 6) and stored energy (150 vs 130 kJ) before the injections did their nasty work on the discharge.

We then went to the best radius for the previous work (1050810) and did a 10 minute 100% duty cycle boronization (65/70/75 cm). This resulted in even better performance - Wtot>170 kJ, Prad_diodex3 ~ 150 kW and dprad/dt ~ 1.8. So, the best of the day at what we think is the best spot and with 10 minutes of boronization.


Entered: Aug 29 2005 09:26:44:567AM
Author: Vincent Tang
Summary for MP389 CNPA Testing and Calibration, first 1/2 of the day:

Out of a total of 15 plasma attempts, we managed to produce 11 useful shots. Most of the planned 600kA and 800kA density scan was completed except for the two nel=0.4e20 shots in the plan. Density control was an issue throughout the day and we were simply not able to achieve densities lower than nel~.55e20 w/RF power. However, we did get data at nel~1e20. The J-port dipole perform respectably and we were able to get ~1.3MW out of it.

In general, the fast ion passive signals were excellent and for some shots each of three F-port channels picked ~ 10k counts. The fast ion energy spectrums were very energetic, with some distributions almost flat from ~100-400keV.

The two newly installed C-port channels perform decently but it took several cell access to find the right aperture size. They should provide information on a different cut of the fast ion phase space.

Because the DNB was semi-operational (w/thanks to R. Granetz and D. Beals) in short pulse low current mode, we spent some time trying to get low density plasmas in order to maximize its effectiveness. This resulted in one shot with clear DNB signal (shot 11), and two other shots where the signal was less obvious.

Finally, on shot 15, we confirmed that the CNPA signal is quite sensitive to edge neutral pressures. The F-port top count rates for shot 15 was dramatically lower compared with other shots because of a much higher neutral edge pressure (up to 4mtorr compared with ~0.5-1mtorr). A repeat of the shot(16) had lower edge pressure and thus much higher count rate. These effects will have to be accounted for in a simulated CNPA diagnostic.

Thanks for everyone's efforts.

Physics Operator Summaries
Entered: Aug 18 2005 06:09:11:300PM
Author: Earl Marmar
This was a decent run.

We got started about 1 hour late while a crowbar circuit for J-4 was repaired.

The first half of the run (MP 389) was run until 1:45, and Vincent was able to collect high energy neutral data on most shots.

The DNB was injected on a few shots.

Shot 10 disrupted early, probably because of a locked mode. For shot 11 and on A-coil feedback was implemented.


The second half of the run also went quite well. There were 3 boronizations:

20 minutes, 50/52/103, 50% duty factor (flashing) before shot 21 (fizzle) and 22 (plasma).

20 minutes, 50/52/103, 100% duty factor (no flashing) before shot 24 (plasma)

10 minutes, 65/70/75, 100% duty factor before shot 25 (plasma)

reducing the prepuff to 8 msec worked quite well again, with shot 21 being the only post-boronization fizzle, and Bz may have been a bit too negative on that shot.

All post-boronization shots started with very promising h-modes which are interupted by impurity injections.

Pump-out time following the 100% duty-cycle boronizations is significantly longer than that following the 50% duty-cycle boronization. We waited for P to get down to 4e-6 (gauge) before going to INIT in each of the first shots following the boronizations.

Summary:

plasmas 20
fizzles 2
dud 1
power supply dud 1
no power cycle 1
test 1

26 total cycles

Session Leader Comments
Aug 18 2005 10:04:44:343AM1050818001Vincent Tangno power test shot
Aug 19 2005 03:29:27:413PM1050818003Vincent Tanggood shot, but no J Port.

good signal on all 5 cnpa channels.

Background for Ortec C-port channel taken


Next shot: repeat
Aug 18 2005 10:21:47:483AM1050818004Vincent TangDud, no plasma.

next shot: repeat
Aug 19 2005 03:30:14:070PM1050818005Vincent TangGood shot, but lots of runaways.

cell access to open up Ch4 ortec C-port aperture.

next shot: repeat


Aug 19 2005 03:30:50:803PM1050818006Vincent TangC aperture at 5...too large, saturated preamp on Ortec detector.

All other channels okay.

next: try to go to .4e20/m3
Aug 19 2005 03:31:25:930PM1050818007Vincent TangC aperture at 5...too large, saturated preamp on detector

All other channels okay. DNB ready for next shot.

Cell acess to trim detector aperture on C

next: try to go to 800kA
Aug 19 2005 02:31:11:320PM1050818008Vincent TangC aperture now at 1 from 5.

All other channels okay.

C is still semi-saturated

DNB fired but signal is not clear because RF trips were right around the same time.

next: turn off J-port, try to keep density down, put E at 1MW. Try to see beam signal.

Aug 18 2005 11:35:55:280AM1050818009Vincent TangDisrupted. try again.

Aug 18 2005 11:51:20:220AM1050818010Vincent TangDisrupted. some e-port data but still no beam.

C-port hor is still semi-saturated.

Cell access to trim down aperture from 1 to .25

Next: repeat w/ beam at 0.6s
Aug 18 2005 05:36:00:490PM1050818011Vincent TangGood shot, see DNB signal.

next: Go to .8e20
Aug 18 2005 12:34:06:407PM1050818012Vincent TangGood shot, but beam at wrong time.

cell access to lower c-aperture some more (down to -1)

next: put 1.25MW J-port on in 2nd segment.
Aug 22 2005 04:53:35:927PM1050818013Vincent TangGood shot, beam at the right time, but no obvious beam signal.

Good data on all other channels, c aperture finally at acceptable level.

Next shot: go to 600kA.

Aug 18 2005 12:58:17:317PM1050818014Vincent TangE faulted, CNPA digitizer froze; reboot.

next shot:repeat.
Aug 18 2005 01:42:36:690PM1050818015Vincent TangEdge neutral pressure is very high (~4mtorr). F-Port signal is very attenuated.

repeat to try to get lower edge pressure
Aug 18 2005 01:43:48:113PM1050818016Vincent TangEdge pressure is lower and signal is better.

Next: try 1040415006 again to get beam and lower density LSN plasma....(best shot last campaign)
Aug 18 2005 01:48:08:393PM1050818017Vincent TangDud. That's it for MP389 for today.

Thank you for everybody's effort.

Vincent

Aug 18 2005 02:42:52:643PM1050818018Bruce Lipschultzfirst shot at evaluate plasma and RF

Disrupts at 1.11s

RF tripping and poor matching. Try again.
Aug 18 2005 02:43:03:550PM1050818019Bruce Lipschultzffizzle
Aug 18 2005 02:57:50:410PM1050818020Bruce Lipschultzshot went ok. 1 MA.

Got close to 2.6 MW before the RF started tripping.

nl04=1.0 before RF
Wtot=11 kJ

Matc hing pretty good.

TF sweep to move the resonance out by ~ 4 cm. No observed change in the IR hot spot on top of the divertor. Although it is farther out than 1050805,

Boronize next - 50/52/103cm, 20 minutes, 50% duty cycle. Using 20% diborane.

Next switch the TF sweep to move the resonance inward by 4 cm.
Aug 18 2005 03:20:17:597PM1050818021Bruce Lipschultzfizzle, post-boronization
Aug 18 2005 04:45:11:597PM1050818022Bruce Lipschultz1st shot post-boronization 50/52/103. 50% duty cycle, 20 minutes.

Radiated power is low prior to an injection of Mo.

Pre-injection
The H factor is 1.5
Wtot = 150 kJ
PRF = 2.4 MW

PRad (diodex3) before H-mode ~ 170-190 kW
dPrad/dt ~ 2.6

After the injection and plasma recovery the radiation is high w/correspondingly poor confinement.
Aug 18 2005 04:49:53:533PM1050818023Bruce Lipschultz2nd shot post-boronization 50/52/103. 50% duty cycle, 20 minutes.

Radiated power is high the ehole shot with correspondingly poor confinement.

PRad (diodex3) before H-mode ~ 310kW
dPRad/dt after H-mode (from diodex1) ~ 6

next, boronization 20 minutes, 50/52/103, 100% duty cycle.
Aug 18 2005 04:42:18:520PM1050818024Bruce Lipschultz1st shot post-boronization 50/52/103. 100% duty cycle, 20 minutes.

Again, like shot 22, very good till a Mo injection.

H89 close to 1
Wtot > 150 kJ
prad (3xdiode) pre-H-mode is 150 kW
dPrad/dt also low - 1.0 (using 1xdiode)

next, boronization for 10 minutes 65/70/75 100% duty cycle
Aug 18 2005 06:09:52:473PM1050818025Bruce Lipschultz1st shot post-boronization 65/70/75. 100% duty cycle, 10 minutes.

Very good till a Mo injection.

H89 close to 1.8 before injection
Wtot > 170 kJ
prad (3xdiode) pre-H-mode is 150 kW
dPrad/dt also low - 1.8 (using 1xdiode)

next, repeat
Aug 22 2005 04:09:17:323PM1050818026Bruce Lipschultz2nd shot post-boronization 65/70/75. 100% duty cycle, 10 minutes.

Good till a Mo injection.

Slightly higher initial density.
H89 close to 1.5 before injection
Wtot ~ 150 kJ
prad (3xdiode) pre-H-mode is 190 kW
dPrad/dt also low - 2.1 (using 1xdiode)

Shot never returns to H-mode even though RF power is high enough and radiation is reasonable.

Physics Operator Comments
Aug 18 2005 09:53:21:407AM1050818001Earl MarmarStart with 50 kA TF test, under PLC control
(engineers want test after mainetenance that was performed on TF systems)
Aug 18 2005 09:52:58:937AM1050818002Earl Marmardelay before shot 2 to work on FMIT#4 crowbar circuit problem
Aug 18 2005 09:55:53:390AM1050818002Earl Marmarload 1050802001
5.2 Tesla, inner wall limited
import segment 1 from 1050812003
reduce prefill puff to 25 msec

TF current to -147300 straight across
nl_04 target to 4e19

no power test - iogr problem during init
Aug 18 2005 10:14:22:610AM1050818003Earl Marmarno pcs changes

plasma
slight hesitation in startup, fill pressure is low
some hards
nl_04 ~ 6e19
J-4 faulted out
E port 1 fault
Aug 18 2005 10:23:31:797AM1050818004Earl Marmaradd 2 msec to prefill puff

dud
B_z looks negative

Aug 18 2005 10:49:24:627AM1050818005Earl MarmarEF4 20 amp less negative before t=0
plasma

a lot of early hards
very slight bounce on startup
Aug 18 2005 10:59:24:797AM1050818006Earl Marmaradd 2 msec to prefill puff (now 29 msec)

plasma
still bouncing
hards a bit better, but still high
Aug 18 2005 11:17:30:093AM1050818007Earl Marmaradd 3 msec to prepuff

nl_04 target to 2.5e19

plasma
still bouncing
early hards
got somewhat lower density (pre-RF)
Aug 18 2005 05:25:35:613PM1050818008Earl MarmarDNB gate valve opening on this shot
add 3 more msec to prepuff

Ip to 800 kA

plasma
Aug 18 2005 11:36:49:797AM1050818009Earl Marmarincrease prefill puff (now 37 ms)
reduce early segment 1 gas puff (after 50 msec)

plasma
hards
early disruption after big injection

Aug 18 2005 11:59:18:127AM1050818010Earl Marmarincrease early segment 1 gas puff (after 50 msec)

plasma
disrupt at .66 s (locked mode?)
early hards significantly lower
Aug 18 2005 12:17:10:703PM1050818011Earl Marmarimplement A-coil feedback
load wire 9, segment 2 from 1050722024 onto segment 2, wire 9
set integrator gate C to 1 at .31 s
zero ACOIL_CUR on ALL_V's screen (segment 2)

plasma
good startup
no hards
A-coil programming looks ok
Aug 18 2005 12:39:19:313PM1050818012Earl Marmarnl_04 target raised to 8e19

plasma
bumpy startup
very high early hards
Aug 18 2005 12:42:11:330PM1050818013Earl Marmarno pcs changes

plasma
better startup
early hards, but not as bad as shot 12
Aug 18 2005 01:02:00:973PM1050818014Earl MarmarIp to 600 kA

plasma
bouncy startup
early hards
Aug 18 2005 01:51:28:160PM1050818015Earl Marmaradd 2 msec to prefill puff (now 39 msec)

plasma
Aug 18 2005 02:23:14:457PM1050818016Earl Marmarplasma

no hards
Aug 18 2005 01:47:30:083PM1050818017Earl Marmargo to SNL diverted
load shot 1040415006
import segment 1 from 1050818017
recalculate Ip predictor
remove offset from clearin

power supply dud; missing various supplies
Aug 18 2005 02:16:22:457PM1050818018Earl MarmarSwitching to MP430 Between-shot boronization
disable DNB gate valve
Machine gate-valves closed for this shot
reduce prepuff by 5 msec

load segment 2 from 1050705018

plasma
short h-modes
disrupt during rf

Aug 18 2005 02:40:15:347PM1050818019Earl Marmarput a-coil feedback back in

nl_04 target to 1.1e20
reduce outer gap (increase RCUR 2 mm)

fizzle

fill looks way too high

Aug 18 2005 02:47:25:800PM1050818020Earl Marmarreduce prefill puff to 25 msec

plasma
nice startup
2 h-modes, second fairly steady
Prad ~ 2 MW (2*\prad_2pi)
Prf to ~2.5 MW with trips
Aug 18 2005 03:17:48:130PM1050818021Earl Marmar20 minutes ECDC before this shot
GA bottle (20% B_2D_6, 80% He)
ECDC scan 50/52/103
50% magnetron duty factor

reduce prefill puff to 8 msec

enter init at P = 4e-6

fizzle
Aug 18 2005 04:05:45:397PM1050818022Earl Marmaref4 10 more negative before t=0
prefill puff to 18 msec

plasma
nice startup
no hards

initial Prad low in H-mode, then injection (Matt Reinke reports it was Moly)
W peaks at 155 kJ, H89 peaks at 1.66
Aug 18 2005 04:04:41:800PM1050818023Earl Marmarno pcs changes

plasma

bouncy startup
some hards

Prad is higher than on shot 22
W peaks at 132 kJ, H89 peaks at 1.45
Aug 18 2005 04:40:02:097PM1050818024Earl Marmarprior to this shot
20 minutes boronization
50/52/103
100% duty factor (no flashing)

prefill puff to 8 msec
remove TF ramp during RF; TF current to -145 kA

enter init at P=4e-6 gauge

plasma
starts looking good in H-mode, then killed by a big, then a bigger injection, followed by disruption
Aug 22 2005 12:57:14:963PM1050818025Earl Marmarprior to this shot
boronization for 10 minutes
scan 65/70/75
100% duty factor (not flashing)

keep prepuff at 8 msec

plasma

good startup
initally very good H-Mode (H89 ~ 1.8, W to 174 kJ) then multiple injections
Aug 18 2005 05:17:58:973PM1050818026Earl Marmarprefill puff to 18 msec
nl_04 target to 1.25e20

plasma
149 kJ, then significant injection takes it out of h-mode.
H89 peaks at about 1.48

Engineering Operator Comments
ShotTimeTypeStatusComment
109:01:13:170AMTestOk50 KA TF test
310:06:57:670AMPlasmaOk
410:20:02:953AMPlasmaOk
510:36:19:670AMPlasmaOk
610:49:11:373AMPlasmaOk
711:02:28:127AMPlasmaOk
811:17:13:890AMPlasmaOk
911:30:43:313AMPlasmaOk
1011:43:13:970AMPlasmaOk
1112:05:56:157PMPlasmaOk
1212:22:14:767PMPlasmaOk
1312:38:04:517PMPlasmaOk
1412:50:23:753PMPlasmaOk
1501:03:08:300PMPlasmaOk
1601:15:46:317PMPlasmaOk
1701:40:35:817PMPlasmaBadEng op error TMX breakers were not reset
1801:59:13:567PMPlasmaOk
1902:15:05:847PMPlasmaOk
2002:27:30:690PMPlasmaOk
2103:12:45:333PMPlasmaOk
2203:25:22:677PMPlasmaOk
2303:40:01:707PMPlasmaOk
2404:21:01:787PMPlasmaOk
2504:53:13:567PMPlasmaOk
2605:05:58:740PMPlasmaOk