Alcator C-Mod Run 1050830 Information

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Miniproposals
Miniproposal:436
Date Filed: 8/29/2005
Title:Tests of Fluorine and Molecular Emission Contamination of MSE Signals and Calibration
First Author:Steve Scott
Session Leader:Steve Scott (shots 1-35)

Operators
Session leader(s):Steve Scott
Physics operator(s):Jim Irby,Earl Marmar
Engineering operator(s):Bill Cochran,Ed Fitzgerald,Bill Parkin

Engineering Operator Run Comment
automatically entered by signon - please replace with real comment

Session Leader Plans
Entered: Aug 30 2005 06:50:49:330AM
Author: Steve Scott
A. Beam-into-gas comparison of deuterium to helium

1. Setup like 1040422012 (EF3 = 0, EF4=0), deuterium puff from -0.4 to +0.38 (B-top piezo), firing DNB from
0.70-0.75 sec. Should get torus pressure = 2.6 mTorr (\g_side_mks or \e_top_mks). This is condition "B"
in the MP.
2. If pressure is less than 2 mTorr or greater than 3 mTorr, adjust puff as necessary.
3. Condition "A" from MP: EF3 = 0, EF4=-4 kA. reference shot = 1040422011.
4. Condition "C" from MP: EF3= 0, EF4 = +5 kA. reference shot = 1040422015. repeat twice.
5. Condition "D" from MP: EF3=+6 kA, EF4 = +5 kA. reference shot = 1040304009 (note change of day).
6. Condition "E" from MP: EF3= 12 kA, EF4 = 5 kA. reference shot = 1040422019.

switch to helium puffing. Start with same puff duration as was used in deuterium. Take 3 shots with
higher and lower puff duration (x 1.5, x 0.5) to maximize MSE signal strength.

repeat steps 1-6 above.

B. Test of fluorine contamination of MSE measurement.

1. Setup limited plasma like reference shot 1050812014, 5.4 T, 0.8 MA, fire DNB at 1.0 sec. Take 2-3 shots
at this baseline condition. Measure fluorine density with McPherson.

2. Puff freon using NINJA inner wall capillary (B16-001). Plenum pressure = 175 Torr, trigger @0.400 sec,
puff duration = 50 ms.

3. Adjust NINJA puff duration (and, if necessary, plenum pressure) so that fluorine density is
increased a factor of 3-10 compared to reference value. A higher ratio is preferred, so long
as the radiated power fraction remains less than 60-70%.

4. Simultaneously, add a xenon puff (plenum=2PSI, 10 ms duration starting 1.3). RF heating 1.3-1.5 sec,
2MW. On alternate shots, turn off the xenon puff.

5. Repeat the shot in #3 2-5 times as needed to get adequate MSE statistics.

6. Take 2-3 more baseline shots without xenon puffing.

C. If a significant difference is observed between helium and deuterium in part A, and if time permits,
return to beam-into-gas and cary out a finer scan in vertical field using helium as the target gas.
3.

Physics Operators Plans
Entered: Aug 29 2005 06:09:30:480PM
Author: Earl Marmar
Engineering setup for Tuesday 30 Aug 2005

MP #436: Tests of Fluorine and Molecular Emission Contamination of MSE Signals and Calibration

Session leader: S. Scott
Physics operator: E. Marmar (with Jim Irby substituting for the first hour or so)

Overnight ECDC in Deuterium, and bake at 60 C.
This run follows the first glow boronization, which was done on Monday afternoon, 1050829 (see Irby logbook entry).

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

Power systems as on 1050812014 (limited, 5.4 tesla, .8 MA, kappa=1.6)

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

Gas Setup:
fill B-Top with 6 psi He Hybrid enabled (PG4)
fill B-side lower with 1.7 psi D2 + 0.3 psi xenon Hybrid DISABLED (PG1)
leave B-side upper with whatever Hybrid DISABLED (PG2)
fill B-main (C-side) with 40 psi D2 Hybrid DISABLED (PG3)
leave NINJA pumped out and DISABLED, but be prepared to fill with freon for the second half of the run.

Disable all diagnostic gate valves for the start of the run

Torvac setup: Gate valves open

No between-shot boronization.



-------------------------------------------------------------------------------
ICRF Setup: ICRF might be required for the second half of the run. It will not be required before noon.

________________________________
We will start with DNB into gas shots (no plasma) using first Helium and later deuterium fill. The fields will be TF + various combinations of PF fields in accordance with the session leader plans.

The second half of the run will be DNB into deuterium plasmas, with inner-wall freon puffing through NINJA.

Session Leader Summaries
Entered: Aug 30 2005 07:04:23:860PM
Author: Matt Reinke
Summary for Xenon Puffing Piggyback

shot time (s) dur (ms) pl
-----------------------------------
022 --- -- yes
023 1.3 10 yes
024 1.2 20 yes
025 1.2 40 yes
026 1.2 80 yes
027 --- -- yes
028 1.2 80 yes
029 0.3 50 dis @ 0.72
030 --- -- fiz
031 --- -- dis @ 0.97
032 --- -- fiz
033 0.3 50 dis @ 1.10
034 0.3 50 dis @ 0.73
035 0.3 50 yes

B Side Lower was filled with 2 PSI 5:1 D_2:Xe mix. After a few shots where we increased the gas puff, we were able to see lower charge states of Xe with a very strong line(s) at 108 Ang which seems to be predominantly Xe XIX. Shots 27 and 28 showed Xe retention in the wall isn't a major issue as the brightness was down by > x5 for a similar discharge from 27 to 28. These shots also showed that at Te < 1 keV that this amount of Xe CAN affect the global Prad.

Shot 35 looked to be the best of the day for me. The line at 108 Ang increases in brightness from 0.5 sec until the RF is turned on and then decreases as it it is burned out by the increase in Te. Repeatable shots of this nature would be useful so that scanning the McPherson would be possible. The lines from Xe XXXI+ that were observed by JT-60 were not seen during any of the shots. According to the Te dependent ionization balances, we should be creating these states in the core, although the line integrated brightness don't appear to be measurable, especially in 2nd order.

We didn't break any new ground for Xe spectroscopy, but we did show that C-Mod can consistently puff Xe without killing a plasma (disruptions were due to other factors). The puffs do seem to be perturbative so I do not recommend continuing this as a piggyback unless the Session Leader doesn't care about Prad.





Entered: Aug 31 2005 12:04:35:640PM
Author: Steve Scott
This was an excellent run day. We accomplished both parts of the experiment:
an evaluation of the effect of molecular deuterium emission on beam-into-gas
shots, and an evaluation of the effect of fluorine on beam-into-plasma shots.

The beam operated very well, delivering solid 6.0 amps for 50ms. Reliability was
excellent during beam-into-gas, and degraded during beam-into-plasma.

On-line analysis suggests that both conjectures discussed in the MP. i.e.
that molecular deuterium emission confuses beam-into-gas, and fluorine
confuses beam-into-plasma, are false.


Evaluation of effect of molecular deuterium emission

Shot Summary ---------- shots -----------

EF3 EF4 deuterium helium

0 0 3 13
0 -5 4 10
0 +5 5, 6 14, 15
6 +5 8 9
12 +5 7, 17 11, 16


Evaluation of effect of fluorine impurity

shot dnb freon xenon Ip RF comment

18 30 --- --- 0.8 1.0 @ 1.3
19 50 --- --- 0.8 2.0 @ 1.3
20 37 40 --- 0.8 2.0 @ 1.3 No Prad or Fl change
21 36 100 --- 0.8 2.0 @ 1.3 Prad & Fl do change
22 50 75 --- 0.8 2.0 @ 1.3
23 50 75 10 @ 1.3 0.8 2.0 @ 1.3
24 -- -- 20 @ 1.2 0.8 2.0 @ 1.3
25 50 -- 40 @ 1.2 0.8 2.0 @ 1.3
26 -- 75 80 @ 1.2 0.8 2.0 @ 1.3
27 38 75 --- 0.8 2.0 @ 1.3

shots for Matt and Vincent: remove freon puff, and move RF earlier

28 2x10 -- 80 @ 1.2 0.8 2.0 @ 0.9
29 50 -- 50 @ 0.3 0.8 disrupted @ 0.72
30 50 -- --- fizzle
31 50 -- --- 0.8 disrupted @ 0.95
32 50 -- --- fizzle
33 30+5 -- 50 @ 0.3 0.6 2.5 @ 0.9 disrupted @ 1.1
34 50 -- 50 @ 0.3 0.8 disrupted @ 0.76
35 4x10 -- 50 @ 0.3 0.8 2.5 @ 0.9

















No freon: shots: 18, 19, 25
with freon: shots: 21, 22, 23, 27

with very little freon (and maybe none at all): 20

Physics Operator Summaries
Entered: Aug 30 2005 05:30:49:017PM
Author: Earl Marmar
This was a good run from the physop point of view. The beam into gas with fields shots went smoothly, and the beam was very reliable.

The plasma half of the run also went reasonably well, and included freon puffing through ninja, and xenon puffing through B-side lower. Late in the day, we tried for lower density (nl_04~4e19) and ran into locked mode/disruption problems. A-coil feedback was enabled for shot 31 and subsequent, but this did not solve the problem. We had some fizzle problems following locked-mode disruptions, but lowering the fill pressure seemed to solve this. On the last shot of the day (35), the plasma was moved harder to the inner wall, and this was a nice shot. The beam was definitely less reliable once we were making plasmas, with multiple trips.

Scorecard:

test shots 3
beam into gas with fields 14
plasmas 16
fizzles 2

total cycles 35

Session Leader Comments
Aug 30 2005 08:06:20:680AM1050830001Steve Scotttest shot. got desired pressure = 2.1 mTorr.
Aug 30 2005 09:21:33:243AM1050830003Steve ScottEf3 = 0 EF4 = 0 good dnb, no faults. MSE signal strength looks OK
0.1 degree uncertainty in several channels
Aug 30 2005 09:29:47:540AM1050830004Steve ScottEF3=0 EF4=-5 good.
Aug 30 2005 09:41:14:697AM1050830005Steve ScottEF3=0 EF4=+5 in deuterium target gas. good.
Aug 30 2005 09:52:45:430AM1050830006Steve Scottexact repeat of previous shot. EF3=0 EF4 = +5. good.
Aug 30 2005 10:19:19:697AM1050830007Steve ScottEF3=12 EF4=5 good.
Aug 30 2005 10:33:53:163AM1050830008Steve ScottEF3=6 EF4 = 5 good ... end of deuterium shots. switch to helium for next shot
Aug 30 2005 10:48:40:587AM1050830009Steve ScottHELIUM target gas starting this shot. EF3=6, EF4=5. good.
got slightly less pressure than previous shot, but signals are
down considerably. So on next shot, increase helium puff by 50%
Aug 30 2005 11:00:54:070AM1050830010Steve Scotthelium target gas. EF3=0, EF4=-5. increased pressure to about 3 mtorr.
signals are actually weaker than last shot. so on next shot, reduce
gas puff by 50% compared to shot 9. good dnb
Aug 30 2005 11:21:49:807AM1050830012Steve Scottno tf. no helium puffing. gas from dnb only.
Aug 30 2005 11:34:38:710AM1050830013Steve Scotthelium target gas. EF3=0 EF4=0 good dnb
Aug 30 2005 11:47:49:100AM1050830014Steve ScottEF3=0 EF4=+5 good dnb into helium.
Aug 30 2005 12:00:34:337PM1050830015Steve Scottasked for 12+5. got EF3-0, EF4=+5. good dnb.
Aug 30 2005 12:21:27:337PM1050830016Steve ScottEF= 12 + 5. good in helium. next: go to deuterium.
Aug 30 2005 12:36:11:180PM1050830017Steve Scottback to deuterium target gas. EF = 12+5 good dnb.
this is the end of the beam-into-gas experiment.
_______________________________________________________
Aug 30 2005 01:18:43:320PM1050830019Steve Scottrepeat. longer dnb. still no freon or xenon puff.
Aug 30 2005 01:40:58:633PM1050830020Steve ScottNINJA freon puff 172 Torr, puff from 0.400 to 0.450.
... no evidence from McPherson of any fluorine
no real change in Prad
35 ms dnb
Aug 30 2005 01:42:02:790PM1050830020Steve ScottNINJA freon puff 172 Torr, puff from 0.400 to 0.450.
... no evidence from McPherson of any fluorine
no real change in Prad
NINJA says change is 0.26 Torr
Aug 30 2005 01:50:03:710PM1050830021Steve Scottdouble the ninja puff, with the same timing (trigger @0.40 sec, 100 ms pulse duration)
change in pressure at NINJA = 0.75 Torr.
dnb 35 ms
Aug 30 2005 01:56:21:570PM1050830021Steve Scottdouble the ninja puff, with the same timing (trigger @0.40 sec, 100 ms pulse duration)
clear change in Prad, fluorine density, and even Nel a little. 35 ms dnb
Aug 30 2005 02:07:07:447PM1050830021Steve Scottdouble the ninja puff, with the same timing (trigger @0.40 sec, 100 ms pulse duration)
delta-P = 0.67 Torr. full length beam
Aug 30 2005 02:16:02:600PM1050830022Steve Scottdecrease NINJA puff to 75 ms.
got delta-P = 0.67. about same Prad as previous shot.
Aug 30 2005 02:19:14:087PM1050830023Steve Scottrepeat previous shot. delta-P = 0.70 Torr. Prad similar to 21 and 22.
zeff increase is about 1.5. good dnb
Aug 30 2005 02:19:56:460PM1050830024Steve Scottdisable NINJA ... no freon puffing.
Aug 30 2005 02:48:02:960PM1050830025Steve Scottno freon puffing. had xenon puffing. good dnb.
Aug 30 2005 03:01:27:040PM1050830026Steve Scottfreon puffed with NINJA, delta-P = 0.67. but no dnb, so repeat next shot.
Aug 30 2005 03:01:52:400PM1050830027Steve ScottNINJA puffing freon.
Aug 30 2005 03:15:55:070PM1050830027Steve ScottNINJA puffing, delta-P = 0.58. 38 ms dnb.
Aug 30 2005 03:45:22:007PM1050830029Steve Scottgood dnb pulse, but plasma disrupted early due to locked mode
Aug 30 2005 04:03:28:647PM1050830031Steve Scottincreasing Prf to 2.5 in order to raise Te some more.

Physics Operator Comments
Aug 30 2005 08:08:31:320AM1050830001Jim Irbyno power test shot --- we have been having problems with the data system

did have gas
Aug 30 2005 08:15:08:210AM1050830002Jim Irbyno power test shot

did have gas
Aug 30 2005 09:20:00:307AM1050830003Jim IrbyTom has data system back in proper operation we think.

loaded shot 1040422012 --- this shot had ef4 and ef3 programmed for current, but we will leave these supplies off for this shot (ef3 control power off to keep gates from firing). Shot will only have TF.

Fizzle detector delayed until 1.0 s, off at 1.1 s.

b-top filled with 6 psi of D2 per SL request

b-top gas programmed full on from -0.55 to +0.38 s --- should give peak ratiomatic pressure of about 2.5 mTorr.

diagnostic gatevalves are closed (TCI/YAG for example)

DNB gatevalve enabled --- Dexter running beam

SL happy with shot, moving to step 3.

Aug 30 2005 09:46:13:007AM1050830005Earl Marmarload segment 1 from 1040422015
readjust PG4 full on from -.551 to +.38 seconds
TF and EF4 are the only coils enabled on the PLC's

got the fields and DNB
Aug 30 2005 10:08:26:447AM1050830006Earl Marmarrepeat

got fields, gas and DNB
Aug 30 2005 10:24:17:007AM1050830007Earl MarmarCondition E
EF3 12 kA
EF4 5 kA
(wires loaded from 1040422019)

still puffing D2 through B top

got the fields, gas and DNB
Aug 30 2005 10:41:42:803AM1050830008Earl MarmarCondition D (like 1040422017)
EF3 6 kA
EF4 5 kA

D2 puffing through B-top

got fields, gas, DNB

Aug 30 2005 10:56:04:790AM1050830009Earl Marmarsame fields (condition D)
B-top plenum switched to He-4 (6 psi)
no change in PG4 programming (on at -0.551, off at +0.38 seconds)

Got the fields, gas and DNB
Aug 30 2005 11:06:05:290AM1050830010Earl MarmarIncrease PG4 gas puff by factor ~1.5
on at -1.017, off at 0.38 s

condition A
EF3 0 kA
EF4 -5 kA

got fields, gas, DNB

Aug 30 2005 11:22:19:977AM1050830011Earl Marmarreduce helium puff to 60% of the amount from shot 9
PG4 on at -.179, off at .38 seconds

condition E
EF3 12 kA
EF4 5 kA

got the fields, gas, DNB
Aug 30 2005 11:22:01:977AM1050830012Earl Marmarno power shot, to test the TF scanner

Will also look at pressure rise due to gas from the DNB

PG4 disabled

got a small pressure rise (torus ion gauge went onto the e-6 scale, starting from 2e-7)
Aug 30 2005 11:54:01:507AM1050830013Earl Marmarcondition B
EF3 0 kA
EF4 0 kA

PG4 back on, still puffing He-4

got fields, gas, DNB
Aug 30 2005 11:58:41:930AM1050830014Earl MarmarCondition C
EF3 0 kA
EF4 5 kA

still puffing He-4 from B-top (PG4)

got fields, gas, DNB
Aug 30 2005 12:00:33:743PM1050830015Earl Marmarcondition E
EF3 12 kA
EF4 5 kA

still puffing He-4 through B-top (PG4)

EF3 not enabled properly,
so got condition C instead
EF3 0 kA
EF4 5 kA

DNB and gas ok
Aug 30 2005 12:13:33:117PM1050830016Earl Marmarcondition E
EF3 12 kA
EF4 5 kA

still puffing He-4 through B-top (PG4)

got fields, gas, DNB
Aug 30 2005 12:55:58:100PM1050830017Earl Marmarcondition E
EF3 12 kA
EF4 5 kA
B-top now filled with 6 psi deuterium
PG4 on at -.551, off at .38 seconds

got fields, gas, DNB
Aug 30 2005 01:08:32:383PM1050830017Earl Marmarcondition E
EF3 12 kA
EF4 5 kA
B-top now filled with 6 psi deuterium
PG4 on at -.551, off at .38 seconds
Aug 30 2005 01:09:15:227PM1050830018Earl Marmargo for plasma

load 1050812014
reduce prefill puff to 30 msec (from 33)
reduce nl_04 target to 6e19

B-top (6PSI D2) and B-main (40 psi D2) enabled

no freon or xenon on this shot

plasma
decent startup

Aug 30 2005 01:39:47:350PM1050830019Earl Marmarnl_04 target to 5.5e19

plasma
slight bounce on startup, hards

nice L-mode with 2 MW RF (inner wall limited), H89~1.25
Aug 30 2005 01:38:45:070PM1050830020Earl Marmarno pcs changes
ninja puffing freon on this shot

plasma
early bounce, hards
Bz looks a bit negative
disrupt in rampdown
Aug 30 2005 02:16:20:493PM1050830021Earl MarmarEF4 20 amp less negative t le 0
add 50 kA "back porch" to TF pulse from 2.6 to 3.25 seconds

plasma
bounce, hards
Aug 30 2005 02:16:00:133PM1050830022Earl Marmaradd 2 msec to prefill puff (now 34 msec)

modify TF rampdown after 1.5 seconds to get to 50kA more quickly

plasma
better startup, no hards
Aug 30 2005 02:25:03:243PM1050830023Earl Marmaradding xenon to the mix
PG1 10 msec puff starting at 1.3 seconds

plasma
no sign of the xenon
Aug 30 2005 02:43:29:197PM1050830024Steve ScottIncrease xenon puff:
PG1 start at 1.2s, open for .020 seconds
35 ms beam, and beam data is bad

Aug 30 2005 03:04:30:273PM1050830024Earl MarmarIncrease xenon puff:
PG1 start at 1.2s, open for .020 seconds

plasma
still no sign of the xenon


Aug 30 2005 03:05:17:663PM1050830025Earl Marmarincrease xenon puff to 40 msec

plasma
still no xenon signal
Aug 30 2005 03:04:46:243PM1050830026Earl Marmarincrease xenon again
PG1 to 80 msec starting at 1.2 s

plasma
starting to see a small startup bounce
hards not bad
Matt saw xenon this time
Aug 30 2005 03:17:31:553PM1050830027Earl Marmaradd 2 msec to prefill puff (now 36 msec)
disable B-side lower (no xenon puff)

plasma
Aug 30 2005 03:33:25:320PM1050830028Earl Marmarmove xenon puff earlier
PG1 start at .5, open for .08 seconds

plasma
Aug 30 2005 03:49:11:757PM1050830029Earl Marmarnl_04 target to 3e19
xenon puff moved earlier and decreased:
pg1 on at .3, off at .35 seconds

plasma
disrupt at 0.73 seconds, looks like a locked mode
Aug 30 2005 03:56:27:850PM1050830030Earl Marmarturn on a-coil feedback (wire 9, segment 2, using the SMW prescription)
fizzle
very late breakdown
Aug 30 2005 04:14:20:267PM1050830031Earl MarmarEF4 10 amp more negative for t le 0

plasma

disrupt at ~1 seconds
A-coil feedback appears to be working, but still getting locked mode problems
Aug 30 2005 04:20:23:923PM1050830032Earl Marmardecrease prefill puff by 2 msec

nl_04 target to 4e19
Ip to 600 kA
xenon puff re-enabled

fizzle
fields look ok
Aug 30 2005 04:43:37:440PM1050830033Earl Marmarno pcs changes

plasma
disrupt at 1.11
still unhappy, lots of radiated power during RF
Aug 30 2005 05:04:13:703PM1050830034Earl Marmarreduce prefill puff by 3 msec
nl_04 target to 5.5e19
Ip to 800kA

plasma
early disrupt
Aug 30 2005 05:03:21:673PM1050830035Earl Marmarclearin 5 mm more negative

plasma

nice shot, but DNB tripped

Engineering Operator Comments
ShotTimeTypeStatusComment
208:07:23:430AMTestOkShot cycle test
309:12:13:617AMTestOkMSE Calibration
409:24:55:350AMTestOkMSE Calibration
509:37:34:273AMTestOkMSE Calibration
609:49:37:600AMTestOkMSE Calibration
710:16:10:180AMTestOkMSE Calibration
810:30:31:133AMTestOkMSE Calibration
910:42:53:790AMTestOkMSE Calibration
1010:55:37:120AMTestOkMSE Calibration
1111:08:29:523AMTestOkMSE Calibration
1211:19:40:163AMTestOkScanner Test
1311:32:07:120AMTestOkMSE test shot
1411:44:39:100AMTestOkMSE test shot
1511:57:01:633AMTestOkMSE test shot
1612:09:21:850PMTestOkMSE test shot
1712:22:32:070PMTestOk
1812:58:13:850PMPlasmaOk
1901:11:58:087PMPlasmaOk
2001:32:32:273PMPlasmaOk
2101:47:47:337PMPlasmaOk
2202:03:43:430PMPlasmaOk
2302:16:04:460PMPlasmaOk
2402:29:17:913PMPlasmaOk
2502:42:07:820PMPlasmaOk
2602:55:25:773PMPlasmaOk
2703:09:40:053PMPlasmaOk
2803:27:16:947PMPlasmaOk
2903:39:58:977PMPlasmaOk
3003:52:31:493PMPlasmaOk
3104:05:03:213PMPlasmaOk
3204:17:34:703PMPlasmaOk
3304:29:58:140PMPlasmaOk
3404:42:40:487PMPlasmaOk
3504:56:21:593PMPlasmaOk