Alcator C-Mod Run 950210 Information

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Miniproposals
Miniproposal:081
Date Filed: 1/22/1995
Title:Li pellet + ICRF ``PEP\'\' Mode
First Author:Yuichi Takase
Session Leader:Yuichi Takase (shots 1-32)

Operators
Session leader(s):Yuichi Takase
Physics operator(s):Steve Wolfe
Engineering operator(s):Vinny Bertolino,Frank Silva

Engineering Operator Run Comment
silva/bertolino takase/

Session Leader Plans

Physics Operators Plans

Session Leader Summaries
Entered: Jul 7 2004 03:49:12:227PM
Author: To Be Determined
Run Summary 950210

SL: Takase
PO: Wolfe
EO: Silva

MP081 PEP Mode (Li pellet + ICRF)

The objective of this run is to optimize PEP mode performance by:
1. scan the target density
2. scanning the current (upwards)
3. varying the pellet size and timing.

A density scan with 2MW of RF power at 850kA was completed.
The density was scanned from nebar=1.0e20 to 2.4e20 m-3.
The maximum neutron rate during the PEP phase was in the range 4e13 to 5e13
per second, and was nearly independent of density. On the other hand,
the stored energy increase was largest at intermediate density,
nebar=1.7e20 to 2.0e20 m-3, and deteriorated at higher and lower
densities.

Towards the end of the run the current was raised to 1.1MA at a density of
nebar=1.9e20 m-3. The stored energy was higher, but the neutron rate was
lower compared to 850kA shots at the same density. The last shot of the
run was a lower density shot (nebar=1.0e20), but we did not get
Li pellet due to a "gate valve fault". More optimization is
clearly needed to enhance the PEP performance at higher current.

Different pellet sizes and timing were tried. Although exhaustive scan
of both timing and pellet size was not completed, there were indications
that a medium pellet injected 30-50msec before the RF pulse worked well.
A medium pellet injected during an RF pulse does not penetrate to the
plasma center. However, an attempt to inject a larger pellet or multiple
pellets caused the plasma to disrupt. When a second pellet was injected
100msec after the first RF pulse (followed by another RF injection),
the PEP mode performance was generally (but not always) not as good as
the first injection.

Because the RF power used today was 2MW to increase reliability,
the record neutron rate (9e13 sec-1) observed previously with 3MW of
RF power (950120016) was not surpassed.

One more run is required to complete this mini-proposal, which should include
1. optimization at higher current
2. PEP mode at lower current
3. higher RF power under the best condition


The following is a brief summary of today's shots:

Starting from 950208028 (from H-mode threshold run, nel_04=1.0e20) with
modified startup.

Shot Ip nel_04 Li pellet RF W_EFIT
target
01 EF3 Test
02 Fiz
03 Pla .85 1.0 none 0.9, 2.5
04 Fiz
05 Pla 1.0 none 0.0, 0.0 smaller R gap
06 Pla 1.0 M@.6 1.1, 1.1 D only
07 Pla 1.0 M@.6, L@.8 1.1, 1.2 76, 47 D only
08 Pla 1.0 M@.6, L@.8 1.6, 1.2 73, 46
09 Pla 1.0 M@.6, L@.8 1.6, 0.4 69
10 Pla (disr) 1.0 M@.6,.7 1.8 74
11 Pla (disr) 1.0 M@(.7),.8 L@.9 1.8 long pulse 79 1st pel fragm
12 Pla (disr) 1.0 M@.7,.8 L@.86 1.4 86
13 Pla 1.0 L@(.75), M@.9 2.1 89 no Lg pel
14 Pla (disr) 1.0 L@.75, M@.9 2.1(?) no data 81
15 Pla (disr) 1.0 L@.75, M@.9 2.1 96
16 Pla (disr) 1.0 M@.64, S&M@.8 2.1 short 85
17 Pla 1.0 M@.64 1.8 short 83 fast ne decay
18 Pla 1.0 M@.62, (.85) ? 74 no 2nd pel
19 Pla 0.6 M@.62, .85 1.7, 1.7 47->67 DAQ1 error
turn YAG node off
20 Pla (disr) 0.6 M@.62, .85
21 Pla (disr) 0.6 M@.67, .90 1.7, 1.6 64
22 Pla 0.8 M@.67, .90 1.8, 1.8 66
23 Pla 1.2 M@(.67), .90 2.1, 2.1 (82) no 1st pel
24 Pla 1.2 M@.67, .90 2.1, 2.2 94
25 Pla 1.4 M@.67, (.90) 2.0(short), 2.2 89 no 2nd pel
26 Pla 1.5 M@(.67), .90 2.0(short), 1.0 (70) no 1st pel
27 Pla 1.5 M@.67, .90 2.1, 2.2 (80,84)
Raise current to 1.1MA
28 Pla (disr) 1.2 M@.67, .90 1.9 (83) no PEP
29 Pla 1.2 M@(.78) 2.0 (97) no pellet
30 Pla 1.2 M@.77, (1.00) 1.0 (97) no 2nd pel
31 Pla 1.2 M@.77, 1.00 2.0, 2.0 68->100
32 Pla 0.8 M@(.77, 1.00) 1.8, 1.9 (59) no pel

Physics Operator Summaries
Entered: Jul 7 2004 04:36:53:177PM
Author: To Be Determined
Physics Operator Summary for Run 950210

SL: Takase
PO: Wolfe
EO: Silva,Bertolino
MP 81 ICRF/Li pellet PEP modes

The plan for this run (the first of two requested for MP81) was to stagger
pellet injections and high-power RF pulses to produce PEP mode behavior.
Planned scans included target density, plasma current, and outer gap.
Unofficial piggyback activities, to keep the operator busy, included
rationalization of the 5.3T startup sequence, extending the shot length, and a
first cut at development for MP89, namely ramping the current down while
holding the shape constant.

The run was partially successful. A density scan was completed at 850kA. Only
one target density, NL_04=1.2e20, was successfully used at 1.1MA; the last shot
was supposed to get a point at 0.8e20, but the LPI gate valve did not open.
Lots of PEP modes and H-modes were observed, but there seems to be plenty left
to do in a second run. Details of the physics results will be found in the
session leader's summary. A new startup segment was developed that seems
pretty robust. Constant shape rampdown, a prerequisite for rampdown to a
second flattop, seems relatively promising. Several shots were ramped down
from 850kA to 470kA in 250msec, with shape control left constant.

The edge people should note that we finally heated up some divertor tiles. The
last few shots caused the temperature of some outer divertor module
thermocouples to ratchet up. One just below the nose (D31-075) reached 175C
after shot 32.

The starting point for the run was 950208028, an 850kA shot with good inner
and outer gaps, elongation ~1.7. The startup in Segment 1 was reworked as
noted below. The outer gap was reduced from ~2cm to ~1.5cm as of shot 5. Aside
from this, the basic equilibrium was not changed all day. A blow-by-blow can
be found in the logbook under the Physics_Operator topic. A brief summary of
the shots follows:

Shot 1 was an EF3 test, to determine if the problem which caused yesterday's
run to be stopped early was fixed. It seemed to be.

Shot 2 fizzled, first try with new startup.

Shot 3-18 were spent trying to get data with RF and pellets and non-disruptive
shots at 850kA and NL_04=1e20. Various timings and combinations of 1,2, or 3
pellets interspersed with RF pulses were tried. Disruptions were common
following the second or third pellet; some but not all could be attributed to
locked modes. There were lots of H-modes and PEP modes on these shots. At shot
15 the programming was extended to run the flattop to 1.25 sec; the idea was
to allow extra time so the pellets could be spaced further apart. Shot 17 (only
one pellet) was the first to actually run successfully with this programming
(but see problems report below).

Shot 19-21 were at a target density of 0.6e20, 1.25 sec flattop (programmed).
20 had an early TF crowbar-this is a weird shot, see problems below. 21 had an
EF3 problem at EOF.

Shot 22 at 0.8e20, also long flattop.

Shot 23-24 at 1.2e20, both long flattops, but OH1 was railing at EOF; shots
survived but moved in near EOF.

Shot 25-27 at 1.5e20; Needed to raise the plenum pressure to 19psi to get the
density up. Had to shorten flattop back to 1.0sec to keep from railing the OH1
at 21kA current limit (increased this later). However, I only brought the
current and density back in to 1 sec, leaving the shape control flat to 1.25;
this is a first cut at the MP89 rampdown scenario, except no second flattop.


Shot 28-31 Current at 1.1MA, NL_04 at 1.2e20. Raised OH1 current limit to 26,
then 27kA to try to avoid railing this supply. Also increased EF4 to
3000Amps. All of these except 29 disrupted either in late flattop or early
rampdown; 29 had no pellet. For 30 and 31 extended flattop back to 1.15sec.
These both railed the OH1 and disrupted shortly thereafter. I attributed the
disruptions to the current rail, but this may not have been true. These had
very high halo currents, one over 200kA (strike 1).

Shot 32 1.1MA, 8e19, flattop to 1.15. This shot made it to 1.2 sec, the RF
was good, but the LPI gate valve didn't open (see Problems). This shot
disrupted similar to 30,31, but the OH1 only reached 24 kA (i.e. did not
rail). The halo current was very close to the magic 250kA (beanball). The only
reason I can see that this, and maybe the others, disrupted, is that the upper
x-point became close to active in the early ramp-down, and was located about
on the upper shelf. This was a consequence of my leaving the shape control
flat till 1.25 instead of ramping the x-points out during ramp-down. These
were clearly very dangerous disruptions, and the cause and cure should be
figured out before we do these again.

The new startup segment proved quite successful. Shots 3,5-32 all went, tying
Earl's record. I recommend using the SEG_01 from any shot after #8 as the
basis for future 5Tesla startups. The changes to segment 1 were as follows:
Copied IC_ef1L programming into IC_EF1U to symmetrize them
Did the same for V_EF1L to V_EF1U
Bring V_EF2U and V_EF2L voltages on earlier
Change Engineer's timing of EF2 starts from -.4 to -.5
Increase RCUR P-gain to 9.5 from .008s to .040s
Rename wires 5,6,8 to UNUSED5,UNUSED6,UNUSED8, zero their predictors
Change SEG_01 wires 5-8 from 'IP' to '10' reference. Aside from being
logically correct for BR_0 on wire 7, this allows a future mod
to start density feedback in SEG_01 on one of these wires.
Change Br_0 offset from 6.e-3 to 7.e-3
Change IC_EF4 from -1035 to -1050A
Drop early PG3 (V program) significantly (note plenum was at set to
19psi to start). These drops were made to get the current rise
up to snuff, namely to reach 400kA by 100msec.
IN addition to these changes in seg_01, I also made changes to the current
ramp around 340msec, and started the CLEARIN much further in and ramped it out
more slowly. The latter seemed to help most with getting EF2's off the rails
(see shot 10).

Problems:
---------
The EF3 problem which caused yesterday's run to end early is not completely
cured. Shots 17 and 21 exhibited the effect. Vinnie did something to the PTs
after 21 and the problem did not recur, but it is not clear it's gone for
good.

Shot 20 had an alternator fault which caused the alternator voltage to be
low from the beginning. As a result, the TF crowbarred before t=0.
Nevertheless, the shot ran getting up to flattop and running along, with the
TF decreasing steadily, until a pellet at about .62 sec finally killed it. The
engineers couldn't explain why an alternator fault and/or a TF crowbar would
not keep the PF supplies from firing, or cause them to fault, but that's not
what happened. This could be a dangerous interlock failure?

The DAQ1 highway was going down all day again. The culprit is in crate 13
(YAG). This crate was removed from the highway at shot 22, and no more
problems (also no more YAG data, a serious loss for a pellet run).

In order to raise the OH1 current limit, it turns out that a pot in the supply
must also be adjusted to avoid spurious (?) comm faults. This was not done
yesterday, but when we finally decided to push to 26kA today, it was. This
seemed to work.

IGOR hung twice: once on shot 2 in store on DAQ1_CAMAC server, which
was cleared by stopping the server; and before shot 30 when GANESA analysis
hung over a network problem.

On two occasions, the LPI gate valve faulted after a shot and it was not
noticed until too late. This included the last shot of the day. It would seem
that either Darren should get some indication of this (its a TORVAC fault not
an LPI system fault) or the gas station engineer should be made aware if such a
fault occurs; the gate valve screen is not typically up during operation,
because that PC has so many functions.

Scorecard
---------
Tests 1
Duds 0
Fizzles 2
Plasmas 29 (28 straight from 5-32, ties Earl's record!)
------- --
Total 32

Session Leader Comments
Feb 10 1995 08:42:26:200AM950210001Yuichi TakaseToday's Run: MP081 PEP Mode (Li pellet + ICRF)
Optimize PEP mode:
Scan density.
Scan current.
Vary pellet size/timing.

Shot 1: EF3 Test

Feb 10 1995 08:49:32:210AM950210002Yuichi TakaseShot 2:
Starting from 950208028 (from H-mode threshold run, nel_04=1.0e20).
Modified startup.

Fizzle.

Feb 10 1995 09:16:26:630AM950210003Yuichi TakaseShot 3:
Good shot, no Li pellet yet.
nel_04=1.0e20 (target, goes up at H-mode transition).
2 RF pulses: 0.4+0.5; 1.2+1.4MW
R/L gap = 2.0/1.5
D port 35kV, E port 50kV
Reduce R gap by 5mm for the next shot.
Li pellets (1 med. @ 0.6s, 1 large @ 0.8s) on next shot.

Feb 10 1995 09:17:59:250AM950210004Yuichi TakaseShot 4:
Fizzle.

Feb 10 1995 09:43:42:780AM950210004Yuichi TakaseShot 5:
Plasma, no Li pellet, no high power RF.
Rgap=1.5cm (need to retune RF).

Feb 10 1995 09:46:45:760AM950210005Yuichi TakaseShot 5:
Plasma, no Li pellet, no high power RF.
Rgap=1.5cm (need to retune RF).

Feb 10 1995 09:56:54:850AM950210006Yuichi TakaseShot 6:
Plasma
medium pellet @ 0.6s
D port only 1.1MW (0.65-0.75s), 1.1MW (0.85-0.95s)

Feb 10 1995 10:41:24:890AM950210007Yuichi TakaseShot 7:
Plasma
medium pellet @ 0.6s, large pellet @ 0.8s
D port only 1.1MW (0.65-0.75s), 1.2MW (0.85-0.95s)
W_EFIT 76kJ (1st pulse) 47kJ (2nd pulse)

Feb 10 1995 10:43:10:110AM950210008Yuichi TakaseShot 8:
Plasma
medium pellet @ 0.6s, large pellet @ 0.8s
1.6MW (0.65-0.75s), 1.2MW (0.85-0.95s)
W_EFIT 73kJ (1st pulse) 46kJ (2nd pulse)

Feb 10 1995 11:13:51:620AM950210009Yuichi TakaseShot 9:
Plasma
medium pellet @ 0.6s, large pellet @ 0.8s
1.6MW (0.65-0.75s, short), 0.4MW (0.85-0.95s)
W_EFIT 69kJ (1st pulse)

Feb 10 1995 11:20:11:110AM950210010Yuichi TakaseShot 10:
Plasma, disrupted
medium pellet @ 0.6s, 0.7s
1.8MW (0.65-0.75s)
W_EFIT 74kJ

Feb 10 1995 11:21:19:040AM950210011Yuichi TakaseShot 11:
Plasma, disrupted
medium pellet @ 0.7s, 0.8s, large @ 0.9s
1.8MW (0.65-0.9s)
W_EFIT 79kJ

Feb 10 1995 11:45:53:320AM950210012Yuichi TakaseShot 12:
Plasma, disrupted
medium pellet @ 0.7s, 0.8s, large @ 0.86s
1.4MW (0.65-0.9s)
W_EFIT 86kJ

Feb 10 1995 12:17:36:790PM950210013Yuichi TakaseShot 13:
Plasma
large pellet @ 0.75s (didn't get it), medium @ 0.9s
2.1MW (0.65-1.0s)
W_EFIT 89kJ

Feb 10 1995 12:24:09:140PM950210014Yuichi TakaseShot 14:
Plasma (disrupt)
large pellet @ 0.75s, medium @ 0.9s
2.1MW (estimated, no RF data)
W_EFIT 81kJ

Feb 10 1995 12:24:42:510PM950210015Yuichi TakaseShot 15:
Plasma (disrupt)
large pellet @ 0.75s, medium @ 0.9s
2.1MW
W_EFIT 96kJ

Feb 10 1995 12:34:39:200PM950210016Yuichi TakaseShot 16:
Plasma (disrupt)
medium pellet @ 0.64s, small + medium @ 0.8s (didn't get small)
2.1MW (short)
W_EFIT 85kJ

Feb 10 1995 12:47:51:160PM950210016Yuichi TakaseShot 16:
Plasma (disrupt)
medium pellet @ 0.64s, small + medium @ 0.8s (didn't get small)
2.1MW (short)
W_EFIT 85kJ

Feb 10 1995 12:52:14:500PM950210017Yuichi TakaseShot 17:
Plasma (no disruption)
medium pellet @ 0.64s
1.8MW (short)
W_EFIT 83kJ

Feb 10 1995 01:14:34:360PM950210018Yuichi TakaseShot 18:
Plasma (no disruption)
medium pellet @ 0.62s, 0.85s (didn't get 2nd pellet)
1.8MW? (2 pulses, no E port data)
W_EFIT 74kJ
nel_04=1.0
start density scan, lower to nel_04=0.6 for next shot

Feb 10 1995 01:29:41:110PM950210019Yuichi TakaseShot 19:
Plasma (no disruption)
medium pellet @ 0.62s, 0.85s
1.8MW? (2 pulses)
W_EFIT 47 -> 67kJ
nel_04=0.6
DAQ1 error
Turn YAG node off

Feb 10 1995 02:08:06:790PM950210020Yuichi TakaseShot 20:
Plasma (disruption)
medium pellet @ 0.62s
nel_04=0.6

Feb 10 1995 02:11:20:540PM950210021Yuichi TakaseShot 21:
Plasma (late disruption)
medium pellet @ 0.67s, 0.90s
nel_04=0.6
P_RF=1.7, 1.6
W_EFIT=64kJ

Feb 10 1995 02:25:28:680PM950210022Yuichi TakaseShot 22:
Plasma (late disruption)
medium pellet @ 0.67s, 0.90s
nel_04=0.8
P_RF=1.8, 1.8
W_EFIT=66kJ

Feb 10 1995 02:49:16:170PM950210023Yuichi TakaseShot 23:
Plasma
medium pellet @ 0.67s, 0.90s (no 1st pellet)
nel_04=1.2
P_RF=2.1, 2.1
W_EFIT=(82kJ) 2nd pellet

Feb 10 1995 02:49:47:350PM950210024Yuichi TakaseShot 24:
Plasma
medium pellet @ 0.67s, 0.90s
nel_04=1.2
P_RF=2.1, 2.2
W_EFIT=94kJ

Feb 10 1995 03:07:52:340PM950210025Yuichi TakaseShot 25:
Plasma
medium pellet @ 0.67s, 0.90s (no 2nd pellet)
nel_04=1.4
P_RF=2.0(short), 2.2
W_EFIT=89kJ

Feb 10 1995 03:18:56:200PM950210026Yuichi TakaseShot 26:
Plasma
medium pellet @ 0.67s, 0.90s (no 1st pellet)
nel_04=1.5
P_RF=2.0(short), 1.0
W_EFIT=(70kJ)

Feb 10 1995 03:28:58:070PM950210027Yuichi TakaseShot 27:
Plasma
medium pellet @ 0.67s, 0.90s
nel_04=1.5
P_RF=1.9, 1.9
W_EFIT=80, 84kJ (2nd pellet was better on this shot).

Feb 10 1995 03:56:58:710PM950210028Yuichi TakaseShot 28:
Plasma (disrupt)
medium pellet @ 0.67s, 0.90s
nel_04=1.2
P_RF=1.9
W_EFIT=(83kJ)
no PEP

Feb 10 1995 04:22:26:850PM950210029Yuichi TakaseShot 29:
Plasma
medium pellet @ 0.78s (no pellet)
nel_04=1.2
P_RF=2.0
W_EFIT=(97kJ)

Feb 10 1995 04:41:00:970PM950210030Yuichi TakaseShot 30:
Plasma
medium pellet @ 0.77s, 1.00s (no 2nd pellet)
nel_04=1.2
P_RF=1.0, 1.0
W_EFIT=97kJ

Feb 10 1995 04:51:32:980PM950210031Yuichi TakaseShot 31:
Plasma
medium pellet @ 0.77s, 1.00s
nel_04=1.2
P_RF=2.0, 2.0
W_EFIT=100kJ

Feb 10 1995 05:04:12:080PM950210032Yuichi TakaseShot 32:
Plasma (disruption, 240kA halo)
medium pellet @ 0.77s, 1.00s (no pellet)
nel_04=0.8
P_RF=1.8, 1.9
W_EFIT=(59kJ)

Physics Operator Comments
Feb 10 1995 07:27:54:700AMSteve WolfeRun 950210
SL: Takase
PO: Wolfe
EO: Silva

MP 081: ICRF PEP modes (Li pellets)

Initial shot setup-
Load from 950208028
Symmetrize startup:
Copy Seg_1 IC_EF1L -> IC_EF1U
Copy Seg_1 V_EF1L -> V_EF1U
Bring up EF2 voltages early (-.69) to allow earlier switch time
Increase Seg_1 RCUR Pgain from 4 to 9.5 from .008 to .040
Get rid of .01 int gain on Strkpsi in Seg2
Hold IC_EF4 at 2000. until 1sec, eliminate first ramp-down point.

Feb 10 1995 07:58:43:360AMSteve WolfeInitial shot setup (continued)-
Turn off late gain on Wire 10 ZCUR in Seg2

Feb 10 1995 08:33:35:330AM950210001Steve WolfeShot # 950210001

Test of EF3 (hopefully fixed from yesterday).

More initial setup cosmetic (and maybe more) changes):
Change SEG1 wires 5,6,8 names to "UNUSEDn", zero predictors
Change SEG1 wires 5-8 to '10' Reference
Do a BUILD_SEG before Load

EF3 test ok
Nothing obviously broken on PCS setup

Feb 10 1995 08:50:41:390AM950210002Steve WolfeShot # 950210002

A-side PLenum pressure to 19psi
Fill to 1.7e-5
LPI and ECE gate valve enabled
TCX and PCX enabled

DAQ1_CAMAC server was hung up in store from the test shot.
I managed to free it by doing a TCL> STOP SERVER DAQ1_CAMAC

Fizzle. Radial field looks negative.
No bounce, never forms

Feb 10 1995 09:02:21:580AM950210003Steve WolfeShot # 950210003

Change Br_0 offset from 6.e-3 to 6.5e-3
Plasma - disrupts on rampdown, got a PF crowbar.
Vertical problem at 0.9 sec but made it through
Breakdown runs out but hangs on.
EF2s kiss the rail at 0.328, but make it through.
Current rise is very slow, only 260kA at 100msec

Feb 10 1995 09:07:41:690AM950210003Steve WolfeShot # 950210003

The null looked much worse on 3 than on 2? Too much Bz, hard to
believe it went!
Good RF pulse got h-modes at each pulse

Feb 10 1995 09:24:36:450AM950210004Steve WolfeShot # 950210004

Drop seg1 gas puff.
Change RCUR from 0.6625 to 0.6645 from .6sec to 1.0sec to reduce gap.
Will have a pellet this time.

Fizzle. Null looks bad again, still some negative radial field, and some
early vertical field. No sign of ECE signal.

Feb 10 1995 09:39:34:620AM950210005Steve WolfeShot # 950210005

Raise BR_0 to 7e-3.
Change IC_EF4 from -1035 to -1050.
Change EF2 start times from -.4 to -.5

Plasma- Still railed the EF2L .
Current raise is better, got top 350kA at 100msec, still not good.
Breakdown still a bit ratty.
Null a little better, still some early Bz.
Gaps look ok.

Feb 10 1995 09:49:49:450AM950210006Steve WolfeShot # 950210006

Drop PG3 point at 17msec.
No other changes. Li pellets are timed for .6 and .8
Enable the Ar for this shot.

Plasma
EF2L still on the rail!
Less hesitation between 10 and 20msec on Ip rise.
Breaks down inside and moves out.
Still only 360kA at 100msec.
Got 1 pellet, RF from only one xmttr.

Feb 10 1995 10:01:25:990AM950210007Steve WolfeShot # 950210007

Lower PG3 in segment 1 (50msec ->)
Plasma -
2 pellets, still a problem with E-port RF.
EF2 still touches the rail.
390kA at 100msec
DAQ1 CAMAC got lost again.

Feb 10 1995 10:24:46:820AM950210008Steve WolfeShot # 950210008

Eliminate 340msec point in Ip program. This reduces the demand during
and after crossover, might help.

Plasma - Moly is up a bit.
EF2 still rails.
Got both pellets. RF still around 1MW.

Feb 10 1995 10:34:43:570AM950210009Steve WolfeShot # 950210009

Tweak clearin ramp early.

Plasma -
EF2L just off the rail.
Got two pellets, RF still not happy.
Snipes says there was a locked mode after 2nd pellet.

Feb 10 1995 10:51:17:280AM950210010Steve WolfeShot # 950210010

Bigger tweak on clearin ramp early (before 500msec)
Pellets at .6,.7,.8 programmed

Disruption after 2nd pellet (.74sec). went up, about 80kA halo.
OH2l pulled out.
On the other side, EF2L is pulled way off the rail at 330.

Feb 10 1995 10:55:36:020AM950210010Steve WolfeShot # 950210010

It looks like a locked mode did it in.

Feb 10 1995 11:11:59:970AM950210011Steve WolfeShot # 950210011

Delay the pellets after RF, .7,.8,.9
No PCS changes.

Plasma - another disruption at 0.9 about 120kA halo.
First pellet was a fragment, last pellet was a plasmacide.
RF stayed on through the 2nd pellet ok.

Feb 10 1995 11:38:09:740AM950210012Steve WolfeShot # 950210012

Change 3rd pellet to 0.86
No PCS changes

Plasma - Another disruption. Looks like the third pellet.
150kA of halo current.
No e-port RF.

Feb 10 1995 11:49:14:250AM950210013Steve WolfeShot # 950210013

pellets at .75 (large), .9 (medium)
Plasma - made it thru
Only got the second pellet. Long H-mode before it,

Feb 10 1995 12:12:37:590PM950210015Steve WolfeShot # 950210015

Extend flattop to 1.25 sec (if we can make it)
Disrupted at .91 or so, so we don't know if it would have worked.
150msec halo current.

Feb 10 1995 12:27:13:420PM950210016Steve WolfeShot # 950210016

Extend flattop to 1.25 sec (if we can make it)
Extend gains on RXL and RXU to 1.25 as well (forgot last time)
Note: I did move the Ip controller switch later. I don't think any
others are time dependent.
Medium pellet at 0.64, small/medium at 0.8

Disrupted at 0.8; halo current 110kA
RF faulted at .7 sec

Feb 10 1995 12:44:25:520PM950210017Steve WolfeShot # 950210017

Extend flattop to 1.25 sec (if we can make it)
No second pellet, see if it's really the culprit

Ran all the way through
Lots of light around e-port antenna
DAQ1 problems again, no RF data?
OH1 gets close to 20kA. There is a small glitch in ZCUR at 1.25

Feb 10 1995 01:02:46:770PM950210018Steve WolfeShot # 950210018

Don't ramp zcur at 1.25sec; see if that's the glitch.
Increase OH1 current limit to 21kA
Pellets at .620 and .850

Made it all the way through. No EFC glitch; it was probably an indirect
effect of OH1 hiting its current limit. Also, on previous shot, EF3 was
doing its single phase funniness at about the same time.
Only got the first pellet. Darren claims it's peppy

Feb 10 1995 01:20:10:410PM950210019Steve WolfeShot # 950210019

Reduce density to 0.6e20
Fizzle detector out to 1.65 sec.

Ran through, saw both pellets.
Both xmitters ran "nicely"
No h-modes this time.

Feb 10 1995 01:36:08:220PM950210020Steve WolfeShot # 950210020

Repeat. There was lots of DAQ1 lossage ob the last one. Reich is
turning off the YAG nodes.

Early disruption at 0.63 sec. TF crowbar.
TF crowbarred before commutation. This one had a halo of around 170kA.
There may have been an alternator problem, or may have fired the pulse
before the alternator was up.

Feb 10 1995 02:01:31:300PM950210021Steve WolfeShot # 950210021

Pellets move to 0.67 and 0.9 sec
No PCS changes.

Plasma disrupted at 1.228 sec.
Ip and RCUR start down and out at 1.1 sec.
Only 90kA halo, but it hit the outside limiter
This one was the EF3 problem again.

Feb 10 1995 02:18:32:940PM950210022Steve WolfeShot # 950210022

Change NL04 to 0.8e20
Crate 13 will be removed from DAQ1 hiway.

Disrupted again at 1.4sec Only about 50kA.
Got both pellets. RF at 1.8 for both pulses. looks good.

Feb 10 1995 02:28:17:020PM950210023Steve WolfeShot # 950210023

Change NL04 to 1.2e20

Made it all the way through.
Only one pellet, good RF, 2MW on each pulse.

Feb 10 1995 02:40:56:500PM950210024Steve WolfeShot # 950210024

Repeat NL04 = 1.2e20
RFs are good. got both pellets.
Ip and RCUR going down and in at 1.1sec
OH1 is on the current rail.

Feb 10 1995 02:55:44:590PM950210025Steve WolfeShot # 950210025

Raise NL04 = 1.5e20
Shorten current and density flatop to 1.0sec.

GOt one pellets, and RF has lots of faulting
Disrupts at 1.35sec, at 260kA. Upward going.
Didn't quite get to 1.5e20 either.

Feb 10 1995 03:12:50:880PM950210026Steve WolfeShot # 950210026

INcrease A-side plenum pressure to 19.2psi (it was down to 16.4)

Plasma ran through. Didn't get second D-port pulse.
Only got second pellet.

Feb 10 1995 03:24:01:810PM950210027Steve WolfeShot # 950210027

Repeat.
Got the pellets. Got the RF.

Feb 10 1995 03:40:50:690PM950210028Steve WolfeShot # 950210028

Density to 1.2e20
Ip to -1.1e6
IC_EF4 to 3000A, current limit to 3500.
Enable shitshooter (Sc)
Raise Ar plenum from 3 to 4psi

Disrupt in flattop.
OH1 is on its 21kA current rail from 850msec on
150kA of halo current.
Got both pellets, first RF looks good.

Feb 10 1995 04:03:57:320PM950210029Steve WolfeShot # 950210029

Raise OH1 reverse current limit to 26ka; Vinnie has to also adjust a
trip in the supply.
Delay RF to .81
One pellet at .78sec
Sc at 0.85

Ran through
No pellet.

Feb 10 1995 04:34:59:910PM950210030Steve WolfeShot # 950210030

Extend density and current flattop to 1.15sec
pellets at .77 and 1.0
Long delay for IGOR hang, then OH1 init failure.

That one disrupted at 1.2
Only got one pellet. OH1 hits the rail (at 24kA) right near 1.15
Only got 1MW on each RF pulse.

Feb 10 1995 04:44:28:980PM950210031Steve WolfeShot # 950210031

Repeat this one; raise OH1 reverse limit to "27kA", which should allow
25 real kA.

Another late disruption.
Made it a little further, but railed at 25000 at 1.16, disrupted at 1.22
Very similar in fact.
GOt RF and pellets. move on

Feb 10 1995 04:48:03:600PM950210031Steve WolfeShot # 950210031

Halo current was 201kA - Strike 1!

Feb 10 1995 05:43:56:490PM950210032Steve WolfeShot # 950210032

Density to 0.8e20
LPI gate valve was closed!**%*)**_(_(!!!
That was a bad disruption - Halo current was 244kA!.
OH1 was not on the rail, either.
RF ran fine. I don't see any power supply related reason for this one
to have disrupted. The only clue from looking at the flux plot is that
the upper x-point gets real close and is located on the upper shelf.

Note: on the last few shots there was significant tile heating on the
outer divertor. One of Brian's tc's (D31-075) reached 175C.

Engineering Operator Comments
ShotTimeTypeStatusComment
108:23:20:160AMTestOkef3 test 8ka o.k
208:45:06:810AMPlasmaOkno faults
308:55:10:640AMPlasmaOkcomm fault ef1L plasma
409:08:43:360AMPlasmaOkno faults, no plasma
509:30:01:920AMPlasmaOkno fault, ef2u,l switch close -0.5 from -0.4 plasma
609:43:21:480AMPlasmaOkno faults
709:55:19:530AMPlasmaOkno faults
810:14:06:300AMPlasmaOkno faults
910:28:14:710AMPlasmaOkno faults
1010:42:31:260AMPlasmaOkdisruption induced comm fault
1111:01:12:870AMPlasmaOkno faults
1211:15:24:520AMPlasmaOkno faults
1311:42:23:380AMPlasmaOkno faults
1411:53:04:250AMPlasmaOkdisruption induced comm faults
1512:08:04:800PMPlasmaOkno faults
1612:20:17:030PMPlasmaOkdisruption induced comm fault
1712:33:54:530PMPlasmaOkno faults
1812:53:57:190PMPlasmaOkno faults
1901:12:06:660PMPlasmaOkno faults
2001:24:09:680PMPlasmaBadentered pulse state before received shot permissive
2101:51:07:780PMPlasmaOkno faults but EF3 voltage irregular
2202:11:43:810PMPlasmaOkno faults
2302:22:15:280PMPlasmaOkno faults
2402:33:46:440PMPlasmaOkno faults
2502:48:17:400PMPlasmaOkno faults
2603:05:14:620PMPlasmaOkno faults
2703:17:02:140PMPlasmaOkno faults
2803:32:20:380PMPlasmaOkcomm faults oh1,oh2u
2903:56:30:370PMPlasmaOkno faults
3004:23:07:960PMPlasmaOkno faults
3104:40:04:410PMPlasmaOkno faults
3204:51:49:130PMPlasmaOkno faults