Alcator C-Mod Run 990423 Information

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Miniproposals
Miniproposal:237
Date Filed: 3/10/1999
Title:Scaling of Toroidal Rotation with Plasma Current
First Author:John Rice
Session Leader:John Rice (shots 1-28)

Operators
Session leader(s):John Rice
Physics operator(s):John Goetz
Engineering operator(s):Frank Silva

Engineering Operator Run Comment
MP#237

Session Leader Plans

Physics Operators Plans

Session Leader Summaries
Entered: Jul 7 2004 03:49:20:337PM
Author: To Be Determined
Run summary for 990423, MP237, Toroidal Rotation during Plasma Current Scan

The purpose of this run was to determine the scaling of the rotation
velocity with plasma current, for otherwise constant target plasmas,
for H-mode discharges. The range of currents achieved was from 0.4 to 1.4 MA,
however the quality of the H-modes erratic, rendering the results of
this scan nebulous. Other extraneous results were obtained, including
some edge temperature pedestal profiles in H-mode at high current and
impurity confinement scalings with plasma current. Further analysis of
the rotation velocities will be forthcoming.

Physics Operator Summaries
Entered: Jul 7 2004 04:37:00:990PM
Author: To Be Determined
Physics operator summary for 990423

EO: Silva
PO: Goetz
SL: Rice

Run 990423 was in support of Mini-Proposal #237: Scaling of Rotation with Ip.
This run will attempt to confirm/quantify/characterize the scaling of the
toroidal rotation velocity with plasma current during ICRF heating.

The run today was not a success due to the difficulty of producing high quality
H-modes. See the session leader's summary for an
in depth discussion of the experiments performed.

The run started off with fizzles on two of the first four shots. After that,
it was nothing but plasmas. The first fizzle was due to too much radial field.
The second fizzle may have been from the post-boronization blues. For most of
the beginning of the run, there were current rise hesitations and the plasma
would not "pump-out" the midplane neutral pressure. As the day went on, the
breakdown became more "normal" and good plasmas were produced throughout.
However, good quality H-modes were difficult to obtain today.

The plasma current was scanned from 0.4 to 1.3MA during the run. Changes were
made to EF4, RCUR, and CLEARIN to compensate for the IP change. EF4 was
increased/decreased in tandem with IP. RCUR and CLEARIN were pushed to the
plasma center as the current was raised. At the highest current of 1.4MA, an
early disruption occured. The only supply that looked like it was on the rail
was EF4. The PLC current limit was raised and the EF4 and IP currents were
lowered slightly. Subsequent plasmas survived, although the EF4 was very close
to its current limit. The majority of plasmas lasted until 1.7s when the power
supplies were turned off.

Engineering, computing, and diagnostics today:
Two instances of cell access for TCI laser power problems. There is
a leak in the J-Bottom piezoelectric valve [ 2psi of Kr caused a 3e-8
partial pressure in the torus ]. The RF cabal had another tough day
with arcing and what-not.

Scorecard: 28 shots = 26 plasmas + 2 fizzles + 0 duds + 0 tests

Shot summary for Run 990423:

Load 990421006
controller for NL04 returned to PG3 in segment 2
copy V_PG5 to V_PG3 in segment 2
coldstart hybrid - everything loaded; all matrices respond

Shot change result
____ _____ ______
1 see above fizzle; weak one; b.d. @ .006; Br=+.001
P0=.044mTorr

2 BR_0=.001; PG4=18ms plasma; b.d. @ .005; hesitation @.013
from a bounce

3 no changes plasma; b.d. @ .005; good current rise
disr. @ 1.63

4 7.5kA Bt wiggle @ 0.75 fizzle; b.d. @ .005; bounces off
something @ .015

5 BR_0=.00125; PG4=19ms plasma; b.d. @ .005; bounces @ .015
rubs on something @ 0.8s

6 PG4=20ms; Bt wiggles to 0.95s plasma; b.d. @ .005; nice current rise
ZCUR=-.005; 30ms x 100V @ 0.3s
on PG2 with 6 PSI H2

7 IP = -580000 plasma; b.d. @ .005; nice current rise
disrupts @ .79; kappa=1.65

8 CLEARIN=-.01; TF wiggles to plasma; b.d. @ .004; nice current rise
0.85s kappa=1.65

9 RCUR=.671 plasma; b.d. @ .005; o.k. current rise
outer gap = 1cm

10 RCUR=.673; CLEARIN=-.012 plasma; b.d. @ .005; nice current rise
outer gap = .7cm; kappa ~ 1.62

11 IP=-390000; EF4=2600 in seg 2; plasma; b.d. @ .005; o.k. current rise;
PG3=60V in seg 1 disrupts @ 0.33; kappa = 1.69;
n/n_crit = 1.3

12 PG2=50ms; CLEARIN=-.018; plasma; b.d. @ .005; o.k. current rise;
slow down ZXL ramp; mover RCUR disrupts @ 1.34; o.gap=1cm; kappa=1.6
out earlier; slow down IP ramp
to 0.4MA

13 RCUR=.674; slow down IP ramp plasma; b.d. @ .005; o.k. current rise;
disrupts @ 1.34; gaps jumping around

14 IP=-490000; EF4=2800 in seg 2 plasma; b.d. @ .005; good current rise;
disrupts @ 1.34; antenna injects
something @ 0.74s

15 no changes plasma; b.d. @ .005; good current rise;
no big injections

16 IP=-780000; CLEARIN=-.014; plasma; good startup; no injections
RCUR=.672; EF4=3000A in seg2;
less PG3 in seg 1

17 IP=-970000; CLEARIN=-.01; plasma; good startup; o.gap=0.6;
RCUR=.669; EF4=3200A in seg2; i.gap=1.0; kappa=1.64; disrupts @ 1.39

18 CLEARIN=-.007 plasma; good startup; o.gap=0.7;
i.gap=1.2; kappa=1.64; disrupts @ 1.70

19 no changes plasma; good startup; just like 018

20 IP = -1196000; EF4 = 3400A; plasma; Ip=-1.2MA; disrupts @ 1.71;
RCUR = 0.668; CLEARIN = -.005 good startup

21 no changes plasma; good startup; looks like 020

22 no changes plasma; good startup; looks like 021

23 IP = -1385000; EF4 = 3700A; plasma; startup hesitation; disrupts
RCUR = .667; CLEARIN = -.0025 at 0.67 because out of EF4

24 IP=-1300000; EF4=3550A; plasma; disrupts @ 1.31; big hesitation;
increase EF4 PLC limit to -8500 EF4 right at the limit

25 EF4=3500A; BR_0=.0015; more plasma; no hesitation; disrupts @ 1.71
PG3 in segment 1

26 no changes plasma; slight hesitation; disrupts @
1.33s;

27 no changes plasma; no hesitation; disrupts @ 1.71

28 no changes plasma; no hesitation; disrupts @ 1.71

Session Leader Comments
Apr 23 1999 09:06:25:263AM990423003Ian HutchinsonUsed @SYS$MANAGER:FAST_CONTROL to set fast magnetics window to .5s start
with length .5s.
Apr 23 1999 09:37:15:200AM990423005Ian HutchinsonSomething was wrong with the previous fast_control. So do the same thing
again.

Physics Operator Comments
Apr 23 1999 07:54:13:060AMJohn GoetzEngineering Setup and Run plan for Friday, 990423:

MP 237 Scaling of Rotation with Ip

Engineering Setup for 990423

Power supplies as for 990421006

Helium ECDC after overnight boronization

TF under hybrid control

Gas setup - fill B-top with 6 psi of D2 Hybrid enabled
fill B-side lower with 1 psi of Ar Hybrid enabled
fill C-side with 30 psi of D2 Hybrid enabled
fill J-bottom with 2 psi of Kr Hybrid disabled

The following gate valves should be enabled, assuming no vacuum problems:

ECE, VUV, IMP INJ

Physics setup

This run will attempt to confirm/quantify/characterize the scaling of the
toroidal rotation velocity with plasma current during ICRF heating. There
will be a roughly constant density current scan of
[.8,.6,.5,.4,.8,1,1.2,1.4,.8]MA performed with about 2.5MW of injected
RF power and 5.4T toroidal field with ECE tweaks.
Apr 23 1999 08:26:13:467AM990423001John GoetzShot 990423001
coldstart hybrid - all matrices respond
load 990421006 with:
controller for NL04 returned to PG3 in segment 2
copy V_PG5 to V_PG3 in segment 2

Results
fizzle; weak one; break down @ .006
BR_0 = .001
fill pressure is low compared to 990421006

Apr 23 1999 08:41:45:123AM990423002John GoetzShot 990423002
BR_0 = .001 (was .002)
PG4 = 18ms (was 16ms)

Results
plasma; disrupts @ 1.6
breakdown @ .005; Br ~ 0; bounces off something @ .013 for a serious hesitation
antenna outgassing? H-mode late

Apr 23 1999 08:58:36:077AM990423003John GoetzShot 990423003
no changes

Results
plasma; disrupts @ 1.63
breakdown @ .005; Br ~ 0; hesitation is gone
H-mode at the normal time

Apr 23 1999 09:27:33:390AM990423004John GoetzShot 990423004
add 7.5kA wiggle to Bt @ 0.75s

Results
fizzle
breakdown @ .005; bounces @ .015, doesn't survive the bounce

Apr 23 1999 09:45:30:843AM990423005John GoetzShot 990423005
BR_0 = .00125
PG4 = 19ms

Results
plasma
breakdown @ .005; bounces @ .015, survives the bounce
rubs on something @ 0.8s; or something drips in
Apr 23 1999 10:02:19:280AM990423006John GoetzShot 990423006
move Bt wiggles to 0.95s
PG4 = 20ms
ZCUR = -.005 (was -.01)
30ms x 100V on PG2 @ 0.3s in segment 2 (plenum has 6 PSI hydrogen)

Results
plasma - disrupts @ 0.63
breakdown @ .005; no bounce - nice current rise

Apr 23 1999 10:17:39:340AM990423007John GoetzShot 990423007
IP = -580000

Results
plasma - disrupts @ 0.79
this one was in trouble at the beginning of the RF pulse
kappa of about 1.65
breakdown @ .005; no bounce - nice current rise


Apr 23 1999 10:34:45:060AM990423008John GoetzShot 990423008
CLEARIN = -.01 (was -.008)
move TF wiggles to 0.85s

Results
plasma - disrupts @ 1.6
breakdown @ .005; no bounce - nice current rise - Br(0) ~ -.001
kappa still about 1.65 but this one makes it through


Apr 23 1999 10:52:45:687AM990423009John GoetzShot 990423009
RCUR = .671 (outer gap was 1.4cm)

Results
plasma - disrupts @ 1.6
breakdown @ .005; no bounce - nice current rise - Br(0) ~ -.001
outer gap now 1.0s - RF notices no difference - kappa ~ 1.65

Apr 23 1999 11:05:09:437AM990423010John GoetzShot 990423010
RCUR = .673 and CLEARIN = -.012
more PG3 in segment 1 to slow down current ramp rate

Results
plasma - disrupts @ 1.58
breakdown @ .005; nice current rise
outer gap now 0.67cm - RF notices no difference - kappa ~ 1.62
current ramp rate unchanged
Apr 23 1999 11:27:12:437AM990423011John GoetzShot 990423011
IP = -390000
EF4 = 2600A in segment 2
PG3 60V in segment 1

Results
plasma - disrupts @ 0.33
breakdown @ .005; nice current rise
kappa ~ 1.69
n / n_crit = 1.3 - a little vertical instability
Apr 23 1999 11:47:44:437AM990423012John GoetzShot 990423012
move RCUR out earlier
slow down initial ZXL ramp
PG2 = 50ms x 100V @ 0.3s
CLEARIN = -.018
slow down IP ramp down to 0.4MA

Results
plasma - disrupts @ 1.33
breakdown @ .005; nice current rise
kappa ~ 1.60
n / n_crit = 1.3 - a little vertical instability, then n / n_crit = 1.0
poloidal detachment from 0.5 to 0.6s
Mo injection 0.9
heated well, but no H-mode?
Apr 23 1999 12:05:50:530PM990423013John GoetzShot 990423013
RCUR = 0.674
slow down IP ramp down to 0.4MA

Results
plasma - disrupts @ 1.33
breakdown @ .005; nice current rise
kappa ~ 1.60
poloidal detachment from 0.5 to 0.6s
heated well, but no H-mode
looks a lot like 012
Apr 23 1999 12:26:24:937PM990423014John GoetzShot 990423014
IP = -490000
EF4 = 2800A in segment 2
less PG3 early in segment 2

Results
plasma - disrupts @ 1.33
breakdown @ .005; nice current rise
large injection emanating from the antenna; possibly some boron
Apr 23 1999 12:48:46:747PM990423015John GoetzShot 990423015
no changes

Results
plasma - disrupts @ 1.36
breakdown @ .005; nice current rise
no big injections, no H-mode
slight cross-over bump @ 0.76
Apr 23 1999 01:07:47:310PM990423016John GoetzShot 990423016
IP = -780000
CLEARIN = -.014
RCUR = .672
EF4 = 3000A in segment 2
less PG3 in segment 1

Results
plasma - disrupts @ 1.36
breakdown @ .005; nice current rise
a lot better with the RF this time
outer gap to zero late in time
Apr 23 1999 01:23:00:810PM990423017John GoetzShot 990423017
IP = -970000
CLEARIN = -.01
RCUR = .669
EF4 = 3200A in segment 2

Results
plasma - disrupts @ 1.39
breakdown @ .005; nice current rise
outer gap = 0.6cm; inner gap = 1.0cm; kappa = 1.64
Apr 23 1999 01:42:21:937PM990423018John GoetzShot 990423018
CLEARIN = -.007
slow down current in ramp-down [ it was still set for a 0.4MA shot]

Results
plasma - disrupts @ 1.71; fixed with the drawn IP waveform
breakdown @ .005; nice current rise
outer gap = 0.7cm; inner gap = 1.2cm and flat; kappa = 1.64
Apr 23 1999 02:02:06:247PM990423019John GoetzShot 990423019
no changes

Results
plasma - disrupts @ 1.71
breakdown @ .005; nice current rise
same as 018

Apr 23 1999 02:20:00:420PM990423020John GoetzShot 990423020
IP = -1196000
EF4 = 3400A
RCUR = 0.668
CLEARIN = -.005

Results
plasma - Ip = -1.2MA - disrupts @ 1.71
breakdown @ .005; nice current rise
outer gap = 0.6cm; inner gap = 1.3cm; kappa = 1.69

Apr 23 1999 02:36:25:123PM990423021John GoetzShot 990423021
no changes

Results
plasma - disrupts @ 1.71
breakdown @ .005; nice current rise
looks a lot like 020
Apr 23 1999 02:53:16:293PM990423022John GoetzShot 990423022
no changes

Results
plasma - disrupts @ 1.71
breakdown @ .005; nice current rise
looks a lot like 021
Apr 23 1999 03:34:09:140PM990423023John GoetzShot 990423023
IP = -1385000
EF4 = 3700A
RCUR = .667
CLEARIN = -.0025

Results
plasma - disrupts @ 0.67
breakdown @ .005; slight hesitation on this one
it appears that EF4 is near the PLC limit ( it also appears that the 1.5MA shot of
960904038 was also a victim of the EF4 current limit )
benign disruption according to RSG
Apr 23 1999 03:58:09:497PM990423024John GoetzShot 990423024
IP = -1300000
EF4 = 3550A
increase EF4 PLC limit to -8500A

Results
plasma - -1.3MA - disrupts @ 1.31
breakdown @ .006; big hesitation on this one
EF4 is around 4kA and oscillating; still near the limit

Apr 23 1999 04:09:11:543PM990423025John GoetzShot 990423025
BR_0 = .0015
more PG3 in segment 1
EF4 = 3500A

Results
plasma - disrupts @ 1.7
breakdown @ .005; no hesitation on this one
EF4 is around 4kA and oscillating; still near the limit
outer gap = 1cm; inner gap = 1.4cm; kappa=1.7

Apr 23 1999 04:31:44:187PM990423026John GoetzShot 990423026
no changes

Results
plasma - disrupts @ 1.36
breakdown @ .005; slight hesitation on this one
looks a lot like 024
Apr 23 1999 04:49:01:937PM990423027John GoetzShot 990423027
no changes

Results
plasma - disrupts @ 1.71
breakdown @ .005; no hesitation on this one
looks a lot like 025
Apr 23 1999 04:59:48:890PM990423028John GoetzShot 990423028
no changes

Results
plasma - disrupts @ 1.71
breakdown @ .005; no hesitation on this one
looks a lot like 027

Engineering Operator Comments
ShotTimeTypeStatusComment
108:15:49:187AMPlasmaOkno faults/fizzel
208:28:24:263AMPlasmaOkno faults/plasma
308:44:28:873AMPlasmaOkno faults/plasma
409:15:04:403AMPlasmaOkno faults/plasma
509:28:05:233AMPlasmaOkno faults/plasma
609:46:26:250AMPlasmaOkno faults/plasma
710:07:35:280AMPlasmaOkno faults/disruption
810:24:16:403AMPlasmaOkno faults/plasma
910:40:19:873AMPlasmaOkno faults/plasma
1010:58:54:840AMPlasmaOkno faults/plasma
1111:17:13:327AMPlasmaOkno faults/disruption
1211:32:45:077AMPlasmaOkno faults/plasma
1311:51:42:903AMPlasmaOkno faults/plasma
1412:08:52:873PMPlasmaOkNo Faults
1512:36:40:310PMPlasmaOkNo Faults
1612:56:32:263PMPlasmaOkNo Faults
1701:16:00:030PMPlasmaOkNo Faults
1801:32:40:623PMPlasmaOkNo Faults
1901:52:49:530PMPlasmaOkNo Faults
2002:11:39:733PMPlasmaOkNo Faults
2102:30:01:233PMPlasmaOkNo Faults
2202:47:41:640PMPlasmaOkNo Faults
2303:07:08:873PMPlasmaOkNo Faults
2403:41:41:310PMPlasmaOkNo Faults
2504:00:06:093PMPlasmaOkNo Faults
2604:16:24:700PMPlasmaOkNo Faults
2704:40:54:153PMPlasmaOkNo Faults
2804:56:17:700PMPlasmaOkNo Faults