Alcator C-Mod Run 950413 Information

Miniproposals

Miniproposal: 093

Date Filed: 3/1/1995

Title: ICRF H-Mode Density Scan with Reversed Toroidal Field

First Author: Joseph Snipes

Session Leader: Joseph Snipes (shots 1-34)

Operators
Session leader(s):	Joseph Snipes
Physics operator(s):	John Goetz
Engineering operator(s):	Frank Silva, Unknown,Joe Daigle

Engineering Operator Run Comment
Snipe

Session Leader Plans

Physics Operators Plans

Session Leader Summaries

Entered: Jul 7 2004 03:49:13:507PM

Author: To Be Determined

MP093 ICRF H-mode Threshold with Ion Grad B drift away from lower SNX Point

Engineer in Charge: Frank Silva
Physics Operator: John Goetz
Session Leader: Joseph Snipes

This run will start with shot 950412015, except that the plasma current
will be raised to 0.8 MA and the inner and outer gaps will be increased to
1.5 cm or so. Also, the density will be ramped from nl04 = 1.0 x 10^20 m^-2
to 0.7 x 10^20 m^-2 during the current flattop. ECDC should be performed
in helium for a couple of hours before the run. The plan will be to push
as much ICRF power as possible into standard SNX point plasmas to attempt
to get H-modes with the ion grad B drift away from the X point. A scan in
density will be made to improve the H-mode threshold and to attempt to get
as high an input RF power as possible. The outer gap will also be scanned.

There were no H-modes observed throughout the day even with up to 2.7 MW of
ICRF power, albeit for short periods of time. Still, the RF got up to 2.4
MW for more than 250 msec, which should be sufficient to get H-mode with
P/(nBS) values up to 0.06. Nonetheless, a couple of attempts with upper
single null X points with up to 2.4 MW of RF still exhibited at most a bit
of dithering and no H-modes even with P/(nBS) up to 0.06. So, it seems
that the H-mode thresholds are significantly higher than normal whether or
not the ion grad B drift is toward the X point. Carbon levels are low, but
the moly levels do increase dramatically during high power RF. The plasmas
seem to run better with the field reversed. Perhaps there is a broken moly
tile sticking up and making the plasmas run dirtier. Clearly, the present
machine conditions are not conducive to H-modes.

The machine ran very well with almost no problems. There was only a short
delay due to a mysterious TF fault that did not appear in the control room
and made the TF not fire for shot 13. Otherwise, engineering did an
excellent job today. The RF worked reasonably well, though we could not
get above 2.7 MW peak and not above 2.4 MW for any length of time. Still,
it put a reasonable upper limit on the H-mode threshold, but given that we
could not get H-modes even with an upper null X point, it may be more
because the machine is dirty than because the direction of the grad B drift
influences the H-mode threshold.

Shot 01: Fizzle
02: Plasma. Disrupted at 0.5 sec.
03: Good shot. Density lower than requested.
04: Good shot. Density still lower than requested.
05: Good shot. Some hard x rays. RF up to 2.2 MW
06: Good shot. RF at 1.0 MW.
07: Good shot. RF at 1.6 MW.
08: Good shot. Raised nel to 1.0 x 10^20 m^-2 flattop. RF at 1.2 MW.
09: Added Ar. Disrupted at 0.53 sec.
10: Good shot. RF up to 2.6 MW for 50 msec.
11: Good shot. RF at 1.5 MW
12: Good shot. RF at 1.5 MW.
13: No plasma. No TF.
14: Good shot. RF up to 2.7 MW for 75 msec.
15: Good shot. RF at 2.8 MW for 100 msec.
16: Good shot. RF at 1.5 MW.
17: Good shot. RF at 2.3 MW for 100 msec.
18: Disrupted at 0.66 sec.
19: Disrupted at 0.7 sec.
20: Good shot. RF at 1.5 MW.
21: Good shot. RF up to 2.5 MW.
22: Good shot. RF up to 2.6 MW for 40 msec.
23: Good shot. RF at 1.5 MW.
24: Density ramp. RF up to 2.4 MW for 150 msec and 2.2 MW for
another 200 msec.
25: Good shot. Density ramp. RF at 2.4 MW.
26: Loaded segment 2 from 950411041. O.K. shot with lower RF power
requested at 1.8 MW.
27: Loaded segment 3 from 950411041. SNU. Good shot. Some dithering
with RF at 2.3 MW for 80 msec and 1.4 to 1.2 MW for 300 msec.
28: Increase gaps, center plasma up down. Good SNU shot. RF up to
2.3 MW for 250 msec interrupted by dithering.
29: Massive wire changes. Too many wireheads take control.
30: ICRF L-mode run with Ip = 400 kA. Disrupted at 0.58 sec.

Physics Operator Summaries

Entered: Jul 7 2004 04:36:53:850PM

Author: To Be Determined

Physics operator summary for 950413

EO: Silva/Paranay/Daigle
PO: Goetz
SL: Snipes

Run 950413 was in support of Mini-Proposal 093 -- ICRF H-Mode Density Scan
with Reversed Toroidal Field. The goal of this MP is to determine the H-mode
power threshold as a function of density with the toroidal field such that the
ion grad B drift direction is away from the dominant x-point.

Setup:
Load 950412015
Changes to segment 2
IP = 800000
NL04 = 1.0e20 @ 0.5; 0.7e20 @ 1.0
RCUR = 0.664
CLEARIN = 1.5e-2
Load segment 2 of 950411041 into segment 3
^
|_ this should have been segment 3
this is an upper x-point shot
NL04 = 1.0e20 @ 0.5; 0.7e20 @ 1.0
RCUR = 0.659
CLEARIN = 1.0e-2
Coldstart hybrid - all matrices respond
P_0 = 2.5e-5

Run Plan:

Push as much ICRF power as possible into these plasmas in an attempt
to achieve H-mode with the ion grad B drift away from the x-point.

This program was carried out. See the Session Leader's summary to
find out the details of the physics aspects of the run.

Some thoughts from today:
-After one episode of hard x-rays, the fill was raised to 2.3e-5
and not changed for the rest of the run. Breakdowns and current
rises were very robust.
-The run was mostly problem free. Some episodes of inner wall fueling
led to the EF2 supplies getting near the current limit. Slowing down
the current rise rate and the density rise rate helped keep the EF2
supplies off the rail.
-Trying to move the upper x-point further out of the machine in order
to increase the distance to the second separatrix with the ZXU
controller led to EF2's on the rail and early disruptions.
-DO NOT run upper null discharges without STRKPSI control. This is
in order to keep the strike points off of the gussets.
-Running with upper STRKPSI control and lower FSP control leads to
double null discharges, e.g., shot 029.

Engineering, computing, and diagnostics today: TF supply did not fire on
one shot. Conduction faults that didn't show up on the PLC screen
are the suspected culprits.

Scorecard: 34 shots = 32 plasmas + 1 fizzle + 1 dud

Shot summary for Run 950413
coldstart hybrid - all matrices respond
2 hours of He ECDC prior to the run
See above setup for starting information
P_0 = 2.5e-5

Shot change result
____ _____ ______
1 see above fizzle - hits something @ .016
Br a little negative

2 BR_0 offset = +.0005; P_0 = 2.0e-5 plasma - disr. @ 0.48
maybe an injection

3 slower IP ramp up and slow down CLEARIN plasma - all the way down

4 lower PG3 between 0.08 and 0.1sec plasma - all the way down
RCUR = 0.666 gaps o.k.; NL04 not quite right

5 raise NL04 P gain to 8 @ 0.45sec plasma - all the way down
2.2MW RF

6 P_0=2.3e-5; NL04 = 1.1 -> 0.7e20 plasma - all the way down
no hards

7 no changes plasma - all the way down

8 NL04 = 1.0e20 from 0.5 to 1.0 plasma - all the way down

9 enable B_SIDE_LOWER plasma - disr. @ 0.53
EF2's on the rail

10 RCUR=0.665; slow down density and plasma - all the way down
current rises

11 no changes plasma - all the way down

12 FSP = -14.5e-3 @ 0.1sec plasma - all the way down
FSP target better

13 no changes DUD - TF supply didn't fire

14 try again plasma - all the way down

15 no changes plasma - all the way down

16 no changes plasma - all the way down

17 ZXU = +.05 plasma - disr. @ 1.44
EF2's & EF1's almost in trouble

18 no changes plasma - disr. @ .66
EF2's on the rail @ 0.58

19 ZXU ramp from .04 to .05 plasma - disr. @ 0.7
EF2's on rail @ 0.58

20 ZXU = +.04 plasma - all the way down

21 no changes plasma - all the way down

22 no changes plasma - all the way down

23 no changes plasma - all the way down

24 NL_04=1.0->0.6e20 plasma - all the way down
density ramp doesn't happen

25 no changes plasma - all the way down

26 turn off segment 2 and turn on plasma - all the way down
segment 3, which is upper x-point wasn't upper null; wrong
segment from 950411041 loaded

27 load segment 3 of 950411041 plasma - disr. @ 1.35
copy EF2_BY_EF4 & FSP into segment 3 gaps too small and FSP can't
NL04 = 1.0 -> 0.6e20 reach

28 RCUR=.664; ZCUR=0.; CLEARIN=8E-3 plasma - disr. @ 1.38
gaps o.k.; some dithering

29 NL04 = 0.8 -> 0.65e20 plasma - disr. @ 1.08
double null

30 load 950412031 (MP #077A); NL04=0.8e20 plasma - disr. @ 0.58
detached plasma

31 slow down density rise plasma - disr. @ 0.73

32 less density rise plasma - disr. @ 0.57

33 NL04 = 0.6e20 plasma - disr. @ 0.77
hard x-rays galore

34 P_0 = 2.5e-5 plasma - disr. @ 0.74

Session Leader Comments

Apr 13 1995 09:48:54:220AM Joseph Snipes MP093 ICRF H-mode Threshold Run with Grad B away from lower SNX Point

This run will start with shot 950412015, except that the plasma current will
be raised to 0.8 MA and the inner and outer gaps will be increased to 1.5 cm or
so. Also, the density will be ramped from nl04 = 1.0 x 10^20 m^-2 to 0.7 x
10^20 m^-2 during the current flattop. ECDC should be performed in helium for
a couple of hours before the run. The plan will be to push as much ICRF power
as possible into standard SNX point plasmas to attempt to get H-modes with the
ion grad B drift away from the X point. A scan in density will be made to
improve the H-mode threshold and to attempt to get as high an input RF power as
possible. The outer gap will also be scanned.

Apr 13 1995 09:50:17:200AM 950413001 Joseph Snipes Shot 1
Copy of shot 950412015 with Ip = 0.8 MA, nel ramp from 1.0 x 10^20 m^-2 to
7 x 10^19 m^-2 from 0.5 to 1 sec.
Fizzle!

Apr 13 1995 09:51:16:290AM 950413002 Joseph Snipes Shot 2
Plasma. Disrupted at 0.5 sec.

Apr 13 1995 09:52:57:560AM 950413003 Joseph Snipes Shot 3
Plasma. Decent shot. RF at 0.3 MW.

Apr 13 1995 09:56:40:180AM 950413004 Joseph Snipes Shot 4
Good shot. RF at 0.6 MW.

Apr 13 1995 09:57:19:700AM 950413005 Joseph Snipes Shot 5
Good shot. Some hard x rays. RF up to 2.2 MW.

Apr 13 1995 09:59:11:650AM 950413006 Joseph Snipes Shot 6
Good shot. RF at 1.0 MW.

Apr 13 1995 10:15:17:660AM 950413007 Joseph Snipes Shot 7
Good shot. RF at 1.6 MW.

Apr 13 1995 10:29:21:460AM 950413008 Joseph Snipes Shot 8
Good shot. RF at 1.2 MW.

Apr 13 1995 11:00:58:580AM 950413009 Joseph Snipes Shot 9
Added Ar puff. Disrupted at 0.53 sec.

Apr 13 1995 11:02:06:840AM 950413010 Joseph Snipes Shot 10
Reduced rate of rise of Ip at crossover. Looks better. Decent shot. RF up
to 2.6 MW for a brief time.

Apr 13 1995 11:15:53:700AM 950413011 Joseph Snipes Shot 11
Good shot. RF at 1.5 MW.

Apr 13 1995 11:21:40:880AM 950413012 Joseph Snipes Shot 12
Good shot. RF at 1.5 MW.

Apr 13 1995 11:52:47:640AM 950413013 Joseph Snipes Shot 13
No plasma. No TF.

Apr 13 1995 11:55:32:710AM 950413014 Joseph Snipes Shot 14
Good shot. RF up to 2.7 MW for 75 msec.

Apr 13 1995 12:17:16:090PM 950413015 Joseph Snipes Shot 15
Good shot. RF up to 2.8 MW for 100 msec.

Apr 13 1995 12:28:30:080PM 950413016 Joseph Snipes Shot 16
Good shot. RF at 1.5 MW.

Apr 13 1995 01:09:39:730PM 950413017 Joseph Snipes Shot 17
Good shot. RF at 2.3 MW for 100 msec.

Apr 13 1995 01:14:32:090PM 950413018 Joseph Snipes Shot 18
Disrupted at 0.66 sec. Small changes to ZXU for shot 17 may have pushed EF2
over its limit.

Apr 13 1995 01:16:38:560PM 950413018 Joseph Snipes Shot 18
Disrupted at 0.66 sec. Small changes to ZXU for shot 17 may have pushed EF2
over its limit. The RF raises the density as it comes on and that drives EF2
even further leading to the disruption.

Apr 13 1995 01:21:48:790PM 950413019 Joseph Snipes Shot 19
Disrupted at 0.7 sec.

Apr 13 1995 01:46:09:440PM 950413020 Joseph Snipes Shot 20
Good shot. RF at 1.5 MW

Apr 13 1995 02:14:58:830PM 950413021 Joseph Snipes Shot 21
Good shot. RF up to 2.5 MW. P/(nBS) = 0.06 with no sign of H-mode.

Apr 13 1995 02:15:31:140PM 950413022 Joseph Snipes Shot 22
Good shot. RF up to 2.6 MW but only for 40 msec.

Apr 13 1995 02:21:36:800PM 950413023 Joseph Snipes Shot 23
Good shot. RF at 1.5 MW.

Apr 13 1995 02:38:59:940PM 950413024 Joseph Snipes Shot 24
Density ramp from 1.0 to 0.7 x 10^20 m^-2 from 0.5 to 1 sec.
Good shot. RF up to 2.4 MW for 150 msec and 2.2 MW for another 200 msec.

Apr 13 1995 03:09:14:180PM 950413026 Joseph Snipes Shot 26
Loaded wrong segment from shot 950411041 trying to get an upper single null X
point. Reduced RF power to 1.8 MW.

Apr 13 1995 03:29:58:370PM 950413027 Joseph Snipes Shot 27
Loaded segment 3 from shot 950411041 trying to get an upper single null X
point. RF up to 2.3 MW for 80 msec then 1.4 to 1.2 MW for 300 msec.
Some dithering during RF.

Apr 13 1995 03:37:55:370PM 950413028 Joseph Snipes Shot 28
Upper null X point. RF up to 2.3 MW for 250 msec interrupted by dithering.

Apr 13 1995 04:19:13:310PM 950413029 Joseph Snipes Shot 29
Massive wire changes to "improve" STRKPSI control of the upper X point.
RF at 2.3 MW with a ratty plasma with high moly emission. The FSP controller
did not work well. However, an edict has been made that we cannot run upper
null X point plasmas without STRKPSI control. So, I'm punting and turning
the program over to Yuichi to do Ip = 400 kA ICRF L-mode plasmas.

Apr 13 1995 04:42:59:430PM 950413029 Joseph Snipes There were no H-modes throughout the day, even with 2.3 MW of RF and an
upper single null X point. So, it seems that the H-mode thresholds with the
fields in this direction are higher with or without the ion grad B drift in
the direction of the X point. The P/(nBS) values reached 0.06 with the SNB
and with the SNU. So, it seems that the present machine conditions are not
conducive to H-modes with or without the ion grad B drift direction toward
the X point.

Physics Operator Comments

Apr 13 1995 08:12:30:710AM John Goetz Run 950413:
In support of Mini-Proposal #093 -- ICRF H-Mode Density Scan
with Reversed Toroidal Field. The goal of this MP is to determine
the H-mode power threshold as a function of density with the toroidal
field such that the ion grad B drift direction is away from the
dominant x-point.

Run Plan:
Push as much ICRF power as possible into these plasmas in an
attempt to achieve H-mode with the ion grad B drift away from the
x-point.

Apr 13 1995 08:13:31:550AM John Goetz Run 950413:

Setup:
Load 950412015
Changes to segment 2
IP = 800000
NL04 = 1.0e20 @ 0.5; 0.7e20 @ 1.0
RCUR = 0.664
CLEARIN = 1.5e-2
Load segment 2 of 950411041 into segment 3
this is an upper x-point shot
NL04 = 1.0e20 @ 0.5; 0.7e20 @ 1.0
RCUR = 0.659
CLEARIN = 1.0e-2
Coldstart hybrid - all matrices respond
P_0 = 2.5e-5

Apr 13 1995 08:43:56:180AM 950413001 John Goetz Shot 950413001:
P_0 = 2.5e-5

Results:
fizzle - hits something at .016
Br a little bit negative

Apr 13 1995 08:59:20:990AM 950413002 John Goetz Shot 950413002:
P_0 = 2.0e-5
BR_0 offset = +.0005

Results:
plasma - disruption @ 0.48
EF2's on the rail, but between 0.3 & 0.4
maybe an injection?

Apr 13 1995 09:14:43:430AM 950413003 John Goetz Shot 950413003:
slow down IP ramp up and slow down CLEARIN ramp
to save the EF2's

Results:
plasma - all the way down
density event from 0.68 to 0.85sec
too much density early in the current rise

Apr 13 1995 09:26:16:070AM 950413004 John Goetz Shot 950413004:
lower PG3 between 0.08 and 0.1sec
RCUR = 0.666

Results:
plasma - all the way down
NL04 ramp from 0.95 to 0.83 (not what was requested)
RF about 0.6MW

Apr 13 1995 09:41:26:200AM 950413005 John Goetz Shot 950413005:
raise NL04 P gain in two steps, to 8, from 0.4 to 0.45sec

Results:
plasma - all the way down
NL04 gets to 1.0e20 but doesn't ramp down very well
Prf = 2.2MW
no H-mode

Apr 13 1995 09:59:10:780AM 950413006 John Goetz Shot 950413006:
raise P_0 to 2.3e-5 to get rid of hards early
NL04 = 1.1 -> 0.7e20

Results:
plasma - all the way down
hard x-rays have disappeared
Prf only 1MW

Apr 13 1995 10:13:33:820AM 950413007 John Goetz Shot 950413007:
no changes

Results:
plasma - all the way down
Prf = 1.6MW

Apr 13 1995 10:27:38:640AM 950413008 John Goetz Shot 950413008:
NL04 = 1.0e20 from 0.5 to 1.0sec

Results:
plasma - all the way down
Prf = 1.2MW
wall fueling event @ 0.3sec

Apr 13 1995 10:42:45:310AM 950413009 John Goetz Shot 950413009:
enable B_SIDE_LOWER

Results:
plasma - disr. @ 0.53
EF2's on rail - more than likely due to density rise @ 0.3sec

Apr 13 1995 10:58:25:640AM 950413010 John Goetz Shot 950413010:
RCUR = 0.665
slow down density and current rises

Results:
plasma - all the way down
EF2's only 3200A - wall fueling at cross-over is small

Apr 13 1995 10:59:31:660AM 950413010 John Goetz Shot 950413010:
RCUR = 0.665
slow down density and current rises

Results:
plasma - all the way down
EF2's only 3200A - wall fueling at cross-over is small

Apr 13 1995 11:15:15:030AM 950413011 John Goetz Shot 950413011:
no changes

Results:
plasma - all the way down

Apr 13 1995 11:33:25:600AM 950413012 John Goetz Shot 950413012:
FSP=-14.5e-3 @ 0.1sec (target is drifting a bit)

Results:
plasma - all the way down
FSP target better

Apr 13 1995 11:57:39:760AM 950413013 John Goetz Shot 950413013:
no changes

Results:
DUD - TF supply did not fire - possibly some
conduction faluts in the AUX cabinets

Apr 13 1995 12:00:01:490PM 950413014 John Goetz Shot 950413014:
try again

Results:
plasma - all the way down
Prf = 2.7MW

Apr 13 1995 12:17:38:520PM 950413015 John Goetz Shot 950413015:
small deuterium puff on inner wall

Results:
plasma - all the way down
Prf <= 3.0MW for a bit

Apr 13 1995 12:36:18:610PM 950413016 John Goetz Shot 950413016:
no changes

Results:
plasma - all the way down
Prf = 1.5MW

Apr 13 1995 01:05:59:200PM 950413017 John Goetz Shot 950413017:
ZXU = + .05

Results:
plasma - disr. @ 1.44
EF2's kiss the rail @ 0.6
EF1's beginning to kiss voltage rail late in shot

Apr 13 1995 01:14:36:760PM 950413018 John Goetz Shot 950413018:
no changes

Results:
plasma - disr. @ 0.66
EF2's on the rail @ 0.58sec - presumably due to the ZXU change

Apr 13 1995 01:29:33:990PM 950413019 John Goetz Shot 950413019:
turn ZXU change into a ramp

Results:
plasma - disr. @ 0.7
EF2's on the rail @ 0.58
moly monitor signal rises after the RF shuts off?

Apr 13 1995 01:45:13:630PM 950413020 John Goetz Shot 950413020:
ZXU back to +.04

Results:
plasma - all the way down

Apr 13 1995 01:53:26:030PM 950413021 John Goetz Shot 950413021:
no changes

Results:
plasma - all the way down
Prf = 2.5MW for 0.3sec

Apr 13 1995 02:01:18:380PM 950413022 John Goetz Shot 950413022:
no changes

Results:
plasma - all the way down
one transmitter trips

Apr 13 1995 02:22:49:900PM 950413023 John Goetz Shot 950413023:
no changes

Results:
plasma - all the way down
only one antenna ran

Apr 13 1995 02:38:16:960PM 950413024 John Goetz Shot 950413024:
NL_04 = 1.0-> 0.6e20

Results:
plasma - all the way down
Prf = 2.2MW

Apr 13 1995 02:50:40:760PM 950413025 John Goetz Shot 950413025:
no changes

Results:
plasma - all the way down
Prf = 2.4MW

Apr 13 1995 03:12:36:570PM 950413026 John Goetz Shot 950413026:
turn off segment 2 and turn on segment 3, which is an
upper x-point

Results:
plasma - all the way down
was not an upper x-point
the wrong segment from 950411041 was loaded

Apr 13 1995 03:28:24:030PM 950413027 John Goetz Shot 950413027:
load segment 3 of 950411041 into segment 3
copy in EF2_BY_EF4 & FSP from segment 2
NL04 = 1.0 -> 0.6e20

Results:
plasma - disrupts @ 1.35
FSP can't quite reach this one and gaps too small
Prf = 2.3MW for a bit

Apr 13 1995 03:37:30:010PM 950413028 John Goetz Shot 950413028:
RCUR = 0.664
CLEARIN = +8e-3
ZCUR = 0.

Results:
plasma - disrupts @ .138
some dithering
gaps o.k.

Apr 13 1995 04:21:09:460PM 950413029 John Goetz Shot 950413029:
NL04 = 0.8 -> 0.65e20
copy in STRKPSI controller from segment 3 of 950411041
construct FSP controller with ZXA=0.394 and RSOUT=0.685;
ZSOUT=0.6

Results:
plasma - disrupts @ 1.08
mostly double null - kappa > 1.8 for a bit
FSP controller is holding the target

Apr 13 1995 04:36:21:360PM 950413030 John Goetz Shot 950413030:
load 950412031 - startup MP # 077A
NL04 = 0.8e20

Results:
plasma - disr. @ 0.58
detached plasma - killed by RF

Apr 13 1995 04:37:10:040PM 950413031 John Goetz Shot 950413031:
slow down density rise and take some volts off PG3

Results:
plasma - disr. @ 0.73
dies when RF hits 1MW

Apr 13 1995 04:46:43:360PM 950413032 John Goetz Shot 950413032:
slow down density rise some more

Results:
plasma - disrupts @ 0.57
looks like the RF did in another one

Apr 13 1995 04:59:25:480PM 950413033 John Goetz Shot 950413033:
NL04 = 0.6e20

Results:
plasma - disr. @ 0.77
lots of hard x-rays on this one
x-ray Rcentroid jumps out when the RF hits it

Apr 13 1995 05:04:24:190PM 950413034 John Goetz Shot 950413034:
P_0 = 2.5e-5

Results:
plasma - disrupts @ 0.74
density rises - current rolls over - and thats it

Engineering Operator Comments

Shot Time Type Status Comment

1 08:33:13:690AM Plasma Ok no faults

2 08:46:53:050AM Plasma Ok no faults

3 08:59:42:300AM Plasma Ok no faults

4 09:15:14:490AM Plasma Ok no faults

5 09:33:08:570AM Plasma Ok no faults

6 09:49:09:650AM Plasma Ok no faults

7 10:02:47:880AM Plasma Ok no faults

8 10:16:23:740AM Plasma Ok no faults

9 10:29:41:660AM Plasma Ok no faults

10 10:46:27:490AM Plasma Ok Comm Fail OH1, fuses OK

11 11:02:30:640AM Plasma Ok no faults

12 11:16:55:840AM Plasma Ok no faults

13 11:34:50:340AM Plasma Bad TF did not fire, cause unknown

14 11:50:34:770AM Plasma Ok no faults

15 12:08:54:000PM Plasma Ok no faults

16 12:22:22:230PM Plasma Ok no faults

17 12:34:40:840PM Plasma Ok No Faults.

18 01:07:34:530PM Plasma Ok No Faults.

19 01:16:30:550PM Plasma Ok

20 01:32:24:670PM Plasma Ok No Faults.

21 01:44:17:430PM Plasma Ok No Faults.

22 01:56:19:190PM Plasma Ok No Faults.

23 02:15:09:120PM Plasma Ok no faults

24 02:26:23:800PM Plasma Ok No Faults.

25 02:39:12:420PM Plasma Ok No Faults.

26 02:54:29:800PM Plasma Ok No Faults.

27 03:14:00:850PM Plasma Ok No Faults.

28 03:29:25:050PM Plasma Ok No Faults.

29 04:01:11:260PM Plasma Ok No Faults.

30 04:17:22:940PM Plasma Ok No Faults.

31 04:29:46:320PM Plasma Ok No Faults.

32 04:40:15:010PM Plasma Ok No Faults.

33 04:50:50:110PM Plasma Ok No Faults.

34 05:01:00:160PM Plasma Ok No Faults.

Session Leader Comments
Apr 13 1995 09:48:54:220AM		Joseph Snipes	MP093 ICRF H-mode Threshold Run with Grad B away from lower SNX Point This run will start with shot 950412015, except that the plasma current will be raised to 0.8 MA and the inner and outer gaps will be increased to 1.5 cm or so. Also, the density will be ramped from nl04 = 1.0 x 10^20 m^-2 to 0.7 x 10^20 m^-2 during the current flattop. ECDC should be performed in helium for a couple of hours before the run. The plan will be to push as much ICRF power as possible into standard SNX point plasmas to attempt to get H-modes with the ion grad B drift away from the X point. A scan in density will be made to improve the H-mode threshold and to attempt to get as high an input RF power as possible. The outer gap will also be scanned.
Apr 13 1995 09:50:17:200AM	950413001	Joseph Snipes	Shot 1 Copy of shot 950412015 with Ip = 0.8 MA, nel ramp from 1.0 x 10^20 m^-2 to 7 x 10^19 m^-2 from 0.5 to 1 sec. Fizzle!
Apr 13 1995 09:51:16:290AM	950413002	Joseph Snipes	Shot 2 Plasma. Disrupted at 0.5 sec.
Apr 13 1995 09:52:57:560AM	950413003	Joseph Snipes	Shot 3 Plasma. Decent shot. RF at 0.3 MW.
Apr 13 1995 09:56:40:180AM	950413004	Joseph Snipes	Shot 4 Good shot. RF at 0.6 MW.
Apr 13 1995 09:57:19:700AM	950413005	Joseph Snipes	Shot 5 Good shot. Some hard x rays. RF up to 2.2 MW.
Apr 13 1995 09:59:11:650AM	950413006	Joseph Snipes	Shot 6 Good shot. RF at 1.0 MW.
Apr 13 1995 10:15:17:660AM	950413007	Joseph Snipes	Shot 7 Good shot. RF at 1.6 MW.
Apr 13 1995 10:29:21:460AM	950413008	Joseph Snipes	Shot 8 Good shot. RF at 1.2 MW.
Apr 13 1995 11:00:58:580AM	950413009	Joseph Snipes	Shot 9 Added Ar puff. Disrupted at 0.53 sec.
Apr 13 1995 11:02:06:840AM	950413010	Joseph Snipes	Shot 10 Reduced rate of rise of Ip at crossover. Looks better. Decent shot. RF up to 2.6 MW for a brief time.
Apr 13 1995 11:15:53:700AM	950413011	Joseph Snipes	Shot 11 Good shot. RF at 1.5 MW.
Apr 13 1995 11:21:40:880AM	950413012	Joseph Snipes	Shot 12 Good shot. RF at 1.5 MW.
Apr 13 1995 11:52:47:640AM	950413013	Joseph Snipes	Shot 13 No plasma. No TF.
Apr 13 1995 11:55:32:710AM	950413014	Joseph Snipes	Shot 14 Good shot. RF up to 2.7 MW for 75 msec.
Apr 13 1995 12:17:16:090PM	950413015	Joseph Snipes	Shot 15 Good shot. RF up to 2.8 MW for 100 msec.
Apr 13 1995 12:28:30:080PM	950413016	Joseph Snipes	Shot 16 Good shot. RF at 1.5 MW.
Apr 13 1995 01:09:39:730PM	950413017	Joseph Snipes	Shot 17 Good shot. RF at 2.3 MW for 100 msec.
Apr 13 1995 01:14:32:090PM	950413018	Joseph Snipes	Shot 18 Disrupted at 0.66 sec. Small changes to ZXU for shot 17 may have pushed EF2 over its limit.
Apr 13 1995 01:16:38:560PM	950413018	Joseph Snipes	Shot 18 Disrupted at 0.66 sec. Small changes to ZXU for shot 17 may have pushed EF2 over its limit. The RF raises the density as it comes on and that drives EF2 even further leading to the disruption.
Apr 13 1995 01:21:48:790PM	950413019	Joseph Snipes	Shot 19 Disrupted at 0.7 sec.
Apr 13 1995 01:46:09:440PM	950413020	Joseph Snipes	Shot 20 Good shot. RF at 1.5 MW
Apr 13 1995 02:14:58:830PM	950413021	Joseph Snipes	Shot 21 Good shot. RF up to 2.5 MW. P/(nBS) = 0.06 with no sign of H-mode.
Apr 13 1995 02:15:31:140PM	950413022	Joseph Snipes	Shot 22 Good shot. RF up to 2.6 MW but only for 40 msec.
Apr 13 1995 02:21:36:800PM	950413023	Joseph Snipes	Shot 23 Good shot. RF at 1.5 MW.
Apr 13 1995 02:38:59:940PM	950413024	Joseph Snipes	Shot 24 Density ramp from 1.0 to 0.7 x 10^20 m^-2 from 0.5 to 1 sec. Good shot. RF up to 2.4 MW for 150 msec and 2.2 MW for another 200 msec.
Apr 13 1995 03:09:14:180PM	950413026	Joseph Snipes	Shot 26 Loaded wrong segment from shot 950411041 trying to get an upper single null X point. Reduced RF power to 1.8 MW.
Apr 13 1995 03:29:58:370PM	950413027	Joseph Snipes	Shot 27 Loaded segment 3 from shot 950411041 trying to get an upper single null X point. RF up to 2.3 MW for 80 msec then 1.4 to 1.2 MW for 300 msec. Some dithering during RF.
Apr 13 1995 03:37:55:370PM	950413028	Joseph Snipes	Shot 28 Upper null X point. RF up to 2.3 MW for 250 msec interrupted by dithering.
Apr 13 1995 04:19:13:310PM	950413029	Joseph Snipes	Shot 29 Massive wire changes to "improve" STRKPSI control of the upper X point. RF at 2.3 MW with a ratty plasma with high moly emission. The FSP controller did not work well. However, an edict has been made that we cannot run upper null X point plasmas without STRKPSI control. So, I'm punting and turning the program over to Yuichi to do Ip = 400 kA ICRF L-mode plasmas.
Apr 13 1995 04:42:59:430PM	950413029	Joseph Snipes	There were no H-modes throughout the day, even with 2.3 MW of RF and an upper single null X point. So, it seems that the H-mode thresholds with the fields in this direction are higher with or without the ion grad B drift in the direction of the X point. The P/(nBS) values reached 0.06 with the SNB and with the SNU. So, it seems that the present machine conditions are not conducive to H-modes with or without the ion grad B drift direction toward the X point.

Physics Operator Comments
Apr 13 1995 08:12:30:710AM		John Goetz	Run 950413: In support of Mini-Proposal #093 -- ICRF H-Mode Density Scan with Reversed Toroidal Field. The goal of this MP is to determine the H-mode power threshold as a function of density with the toroidal field such that the ion grad B drift direction is away from the dominant x-point. Run Plan: Push as much ICRF power as possible into these plasmas in an attempt to achieve H-mode with the ion grad B drift away from the x-point.
Apr 13 1995 08:13:31:550AM		John Goetz	Run 950413: Setup: Load 950412015 Changes to segment 2 IP = 800000 NL04 = 1.0e20 @ 0.5; 0.7e20 @ 1.0 RCUR = 0.664 CLEARIN = 1.5e-2 Load segment 2 of 950411041 into segment 3 this is an upper x-point shot NL04 = 1.0e20 @ 0.5; 0.7e20 @ 1.0 RCUR = 0.659 CLEARIN = 1.0e-2 Coldstart hybrid - all matrices respond P_0 = 2.5e-5
Apr 13 1995 08:43:56:180AM	950413001	John Goetz	Shot 950413001: P_0 = 2.5e-5 Results: fizzle - hits something at .016 Br a little bit negative
Apr 13 1995 08:59:20:990AM	950413002	John Goetz	Shot 950413002: P_0 = 2.0e-5 BR_0 offset = +.0005 Results: plasma - disruption @ 0.48 EF2's on the rail, but between 0.3 & 0.4 maybe an injection?
Apr 13 1995 09:14:43:430AM	950413003	John Goetz	Shot 950413003: slow down IP ramp up and slow down CLEARIN ramp to save the EF2's Results: plasma - all the way down density event from 0.68 to 0.85sec too much density early in the current rise
Apr 13 1995 09:26:16:070AM	950413004	John Goetz	Shot 950413004: lower PG3 between 0.08 and 0.1sec RCUR = 0.666 Results: plasma - all the way down NL04 ramp from 0.95 to 0.83 (not what was requested) RF about 0.6MW
Apr 13 1995 09:41:26:200AM	950413005	John Goetz	Shot 950413005: raise NL04 P gain in two steps, to 8, from 0.4 to 0.45sec Results: plasma - all the way down NL04 gets to 1.0e20 but doesn't ramp down very well Prf = 2.2MW no H-mode
Apr 13 1995 09:59:10:780AM	950413006	John Goetz	Shot 950413006: raise P_0 to 2.3e-5 to get rid of hards early NL04 = 1.1 -> 0.7e20 Results: plasma - all the way down hard x-rays have disappeared Prf only 1MW
Apr 13 1995 10:13:33:820AM	950413007	John Goetz	Shot 950413007: no changes Results: plasma - all the way down Prf = 1.6MW
Apr 13 1995 10:27:38:640AM	950413008	John Goetz	Shot 950413008: NL04 = 1.0e20 from 0.5 to 1.0sec Results: plasma - all the way down Prf = 1.2MW wall fueling event @ 0.3sec
Apr 13 1995 10:42:45:310AM	950413009	John Goetz	Shot 950413009: enable B_SIDE_LOWER Results: plasma - disr. @ 0.53 EF2's on rail - more than likely due to density rise @ 0.3sec
Apr 13 1995 10:58:25:640AM	950413010	John Goetz	Shot 950413010: RCUR = 0.665 slow down density and current rises Results: plasma - all the way down EF2's only 3200A - wall fueling at cross-over is small
Apr 13 1995 10:59:31:660AM	950413010	John Goetz	Shot 950413010: RCUR = 0.665 slow down density and current rises Results: plasma - all the way down EF2's only 3200A - wall fueling at cross-over is small
Apr 13 1995 11:15:15:030AM	950413011	John Goetz	Shot 950413011: no changes Results: plasma - all the way down
Apr 13 1995 11:33:25:600AM	950413012	John Goetz	Shot 950413012: FSP=-14.5e-3 @ 0.1sec (target is drifting a bit) Results: plasma - all the way down FSP target better
Apr 13 1995 11:57:39:760AM	950413013	John Goetz	Shot 950413013: no changes Results: DUD - TF supply did not fire - possibly some conduction faluts in the AUX cabinets
Apr 13 1995 12:00:01:490PM	950413014	John Goetz	Shot 950413014: try again Results: plasma - all the way down Prf = 2.7MW
Apr 13 1995 12:17:38:520PM	950413015	John Goetz	Shot 950413015: small deuterium puff on inner wall Results: plasma - all the way down Prf <= 3.0MW for a bit
Apr 13 1995 12:36:18:610PM	950413016	John Goetz	Shot 950413016: no changes Results: plasma - all the way down Prf = 1.5MW
Apr 13 1995 01:05:59:200PM	950413017	John Goetz	Shot 950413017: ZXU = + .05 Results: plasma - disr. @ 1.44 EF2's kiss the rail @ 0.6 EF1's beginning to kiss voltage rail late in shot
Apr 13 1995 01:14:36:760PM	950413018	John Goetz	Shot 950413018: no changes Results: plasma - disr. @ 0.66 EF2's on the rail @ 0.58sec - presumably due to the ZXU change
Apr 13 1995 01:29:33:990PM	950413019	John Goetz	Shot 950413019: turn ZXU change into a ramp Results: plasma - disr. @ 0.7 EF2's on the rail @ 0.58 moly monitor signal rises after the RF shuts off?
Apr 13 1995 01:45:13:630PM	950413020	John Goetz	Shot 950413020: ZXU back to +.04 Results: plasma - all the way down
Apr 13 1995 01:53:26:030PM	950413021	John Goetz	Shot 950413021: no changes Results: plasma - all the way down Prf = 2.5MW for 0.3sec
Apr 13 1995 02:01:18:380PM	950413022	John Goetz	Shot 950413022: no changes Results: plasma - all the way down one transmitter trips
Apr 13 1995 02:22:49:900PM	950413023	John Goetz	Shot 950413023: no changes Results: plasma - all the way down only one antenna ran
Apr 13 1995 02:38:16:960PM	950413024	John Goetz	Shot 950413024: NL_04 = 1.0-> 0.6e20 Results: plasma - all the way down Prf = 2.2MW
Apr 13 1995 02:50:40:760PM	950413025	John Goetz	Shot 950413025: no changes Results: plasma - all the way down Prf = 2.4MW
Apr 13 1995 03:12:36:570PM	950413026	John Goetz	Shot 950413026: turn off segment 2 and turn on segment 3, which is an upper x-point Results: plasma - all the way down was not an upper x-point the wrong segment from 950411041 was loaded
Apr 13 1995 03:28:24:030PM	950413027	John Goetz	Shot 950413027: load segment 3 of 950411041 into segment 3 copy in EF2_BY_EF4 & FSP from segment 2 NL04 = 1.0 -> 0.6e20 Results: plasma - disrupts @ 1.35 FSP can't quite reach this one and gaps too small Prf = 2.3MW for a bit
Apr 13 1995 03:37:30:010PM	950413028	John Goetz	Shot 950413028: RCUR = 0.664 CLEARIN = +8e-3 ZCUR = 0. Results: plasma - disrupts @ .138 some dithering gaps o.k.
Apr 13 1995 04:21:09:460PM	950413029	John Goetz	Shot 950413029: NL04 = 0.8 -> 0.65e20 copy in STRKPSI controller from segment 3 of 950411041 construct FSP controller with ZXA=0.394 and RSOUT=0.685; ZSOUT=0.6 Results: plasma - disrupts @ 1.08 mostly double null - kappa > 1.8 for a bit FSP controller is holding the target
Apr 13 1995 04:36:21:360PM	950413030	John Goetz	Shot 950413030: load 950412031 - startup MP # 077A NL04 = 0.8e20 Results: plasma - disr. @ 0.58 detached plasma - killed by RF
Apr 13 1995 04:37:10:040PM	950413031	John Goetz	Shot 950413031: slow down density rise and take some volts off PG3 Results: plasma - disr. @ 0.73 dies when RF hits 1MW
Apr 13 1995 04:46:43:360PM	950413032	John Goetz	Shot 950413032: slow down density rise some more Results: plasma - disrupts @ 0.57 looks like the RF did in another one
Apr 13 1995 04:59:25:480PM	950413033	John Goetz	Shot 950413033: NL04 = 0.6e20 Results: plasma - disr. @ 0.77 lots of hard x-rays on this one x-ray Rcentroid jumps out when the RF hits it
Apr 13 1995 05:04:24:190PM	950413034	John Goetz	Shot 950413034: P_0 = 2.5e-5 Results: plasma - disrupts @ 0.74 density rises - current rolls over - and thats it

Engineering Operator Comments
Shot	Time	Type	Status	Comment
1	08:33:13:690AM	Plasma	Ok	no faults
2	08:46:53:050AM	Plasma	Ok	no faults
3	08:59:42:300AM	Plasma	Ok	no faults
4	09:15:14:490AM	Plasma	Ok	no faults
5	09:33:08:570AM	Plasma	Ok	no faults
6	09:49:09:650AM	Plasma	Ok	no faults
7	10:02:47:880AM	Plasma	Ok	no faults
8	10:16:23:740AM	Plasma	Ok	no faults
9	10:29:41:660AM	Plasma	Ok	no faults
10	10:46:27:490AM	Plasma	Ok	Comm Fail OH1, fuses OK
11	11:02:30:640AM	Plasma	Ok	no faults
12	11:16:55:840AM	Plasma	Ok	no faults
13	11:34:50:340AM	Plasma	Bad	TF did not fire, cause unknown
14	11:50:34:770AM	Plasma	Ok	no faults
15	12:08:54:000PM	Plasma	Ok	no faults
16	12:22:22:230PM	Plasma	Ok	no faults
17	12:34:40:840PM	Plasma	Ok	No Faults.
18	01:07:34:530PM	Plasma	Ok	No Faults.
19	01:16:30:550PM	Plasma	Ok
20	01:32:24:670PM	Plasma	Ok	No Faults.
21	01:44:17:430PM	Plasma	Ok	No Faults.
22	01:56:19:190PM	Plasma	Ok	No Faults.
23	02:15:09:120PM	Plasma	Ok	no faults
24	02:26:23:800PM	Plasma	Ok	No Faults.
25	02:39:12:420PM	Plasma	Ok	No Faults.
26	02:54:29:800PM	Plasma	Ok	No Faults.
27	03:14:00:850PM	Plasma	Ok	No Faults.
28	03:29:25:050PM	Plasma	Ok	No Faults.
29	04:01:11:260PM	Plasma	Ok	No Faults.
30	04:17:22:940PM	Plasma	Ok	No Faults.
31	04:29:46:320PM	Plasma	Ok	No Faults.
32	04:40:15:010PM	Plasma	Ok	No Faults.
33	04:50:50:110PM	Plasma	Ok	No Faults.
34	05:01:00:160PM	Plasma	Ok	No Faults.