Alcator C-Mod Run 1060420 Information

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Miniproposals
Miniproposal:418
Date Filed: 3/4/2005
Title:LH system commisioning
First Author:Stefano Bernabei
Session Leader:John Liptac (shots 1-31)

Operators
Session leader(s):John Liptac
Physics operator(s):Ron Parker,Steve Wolfe,Ron Parker
Engineering operator(s):Ed Fitzgerald,Sam Pierson,Bill Parkin

Engineering Operator Run Comment
MP#418 LH Coupling Studies PO: Parker SL: Liptac/Parker EO: Fitzgerald,P

Session Leader Plans
Entered: Apr 19 2006 05:46:16:910PM
Author: John Liptac
Run Plan 1060420 LH Current Drive

Goal:
1. Drive LH Current

Plasma Conditions:
Begin with the same type of plasmas as produced on 1060413. Low density L-mode, lower single null, nl_04~0.5, B0=5.4 T, and Ip~ 700kA. No ICRF during LH pulses. Load shot 1060310024.

LH setup:
Begin with the launcher at 1585 counts ~1mm behind limiter. Set mechanical phase shifters to 90 degree CD phasing.

Shot 1: two segments, 90 CD phasing.
LH power at 0.695 s. 40kW/klystron.
Setpoint generator settings: Shot Length=200 ms, Duty Cycle=30%, Pulse Period=100 ms.
Shot 2: two segments, 90 CD phasing.
LH power at 0.695 s. 50kW/klystron.
Setpoint generator settings: Shot Length=200 ms, Duty Cycle=50%, Pulse Period=100 ms.
Shot 3: two segments, 90 CD phasing.
LH power at 0.695 s. 55kW/klystron.
Setpoint generator settings: Shot Length=200 ms, Duty Cycle=60%, Pulse Period=100 ms.
Shot 4: two segments, 90 CD phasing.
LH power at 0.695 s. 60kW/klystron.
Setpoint generator settings: Shot Length=200 ms, Duty Cycle=70%, Pulse Period=100 ms.
Shot 5: two segments, 90 CD phasing.
LH power at 0.695 s. 65kW/klystron.
Setpoint generator settings: Shot Length=200 ms, Duty Cycle=80%, Pulse Period=100 ms.
Shot 6: two segments, 90 CD phasing.
LH power at 0.695 s. 70kW/klystron.
Setpoint generator settings: Shot Length=200 ms, Duty Cycle=90%, Pulse Period=100 ms.
Shot 7: two segments, 90 CD phasing.
LH power at 0.695 s. 75kW/klystron.
Setpoint generator settings: Shot Length=200 ms, Duty Cycle=100%, Pulse Period=100 ms

Once this level has been reached begin to change plasma conditions

Explore outer gap ~3 shots.
Limited discharges ~3 shots.
Lower n, Ip ~10 shots or more. Possible phase scan.
Higher B if permitted, phase scan.

Physics Operators Plans
Entered: Apr 19 2006 04:35:37:100PM
Author: Ron Parker
Physop Plan and Engineering Setup for Thursday, April 20


MP#418 LH Coupling studies
SL: Liptac/Parker
PO: Parker

ECDC overnight in D2 at 2.e-4 Torr

Power systems as on 1060413001
A-coil configuration: normal [+Dtop -Dbot -Jtop +Jbot] and enabled.
C-coil Start=0.3sec, Invert=2.0sec

ICRF: J-port in run on status by 7:30

Gas Setup:
----------
fill B-top 6psi D2 Hybrid enabled (PG4)
fill B-side lower 1 psi Argon Hybrid Disabled (PG1)
fill B-side Upper as is, Hybrid Disabled (PG2)
fill B-main 40psi D2 Hybrid Enabled (PG3)
NINJA: 12psi D2

Enable ECE, VUV, Z-bolo shutter assuming no vacuum problems

Run Plan

We will be running low density discharges to continue LH coupling studies with a goal of increasing power and pulse length. The main objective for this run is to produce measurable current drive. The plasmas will be standard L-mode discharges initially with ne_l(04)~ 0.5e20 m-2, BT = 5.4 T and Ip ~ 700 kA. We will try to reduce the density and lower the current in order to have the best chance to see current drive. LH power target will be 75 kW for 200 ms. The coupler will be moved in to 1585, which should be flush with the LH limiter but 5 mm in back of the main limiters. We will spend some time optimizing coupling efficiency. Also in the plan will be a few limited shots and some at higher field, e.g., 8T if permitted.

Session Leader Summaries
Entered: Apr 20 2006 08:06:50:153PM
Author: John Liptac
A very successful run. The goal today was to produce current drive and extend the pulse length and power. Ran 400 ms into plasma and saw evidence of current drive! Max coupled power about 400 kW. LHCD was evedent by the decrease in the loop voltage and a slight increase in the plasma current. The power level was raised up to 85 kW on most klystrons. Pushing the launcher in another mm resulted in lowering the reflection coefficients by ~5%.

Periodic oscillations as well as real arcs were observed. The arcs seemed to be located near the jungle gym couplers and not in the rear waveguide assembly. The power was typically lowered on the offending klystron, and would operate well on susequent shots. Jungle gym protection will be needed for high performance operation, as well as the ability to go near maximum klystron power.

Changing the phase from decreasing to increasing phase resulted in current drive.

Physics Operator Summaries
Entered: Apr 20 2006 05:08:26:500PM
Author: Ron Parker
A good day for the machine and for LH. First indications of current drive were seen after correcting the phase of the fixed phase shifters. Running low density produces lots of runaways, and this confuses the actual amount of current drive due to RF. It was possible to reduce the loop voltage by 2, from 0.9 V to 0.4 V, but not more. As expected the loop voltage reduction decreases with increasing density. Clearly, more power will be needed, but this requires a more elaborate protection system. The klystrons all ran reasonably well at ~ 80 kW each, although klystron 4 was limited to 35 kW to avoid breakdown problems.

The machine ran well with 31 shots fired and only 1 dud.

Session Leader Comments
Apr 20 2006 09:19:29:953AM1060420001John LiptacGoal of today's run is to try and observe a little LH current drive. Power and pulse length will be brought up while the launcher is about flush with the limiter to give better coupling.

Yesterday all klystrons except 2, 4, and 6 were conditioned up to 80kw/klystron for 200 ms. The klystrons that were not test had spoilers on the dummy loads.

Use two 100 ms segments and gradually increase the duty cylce until a 200 ms pulse is created.

Using 90 degree CD phasing
40kW/klystron
Two 30 ms pulses with a 70 ms spacing at 1.2 s when the density is low based on shot 1060413001.

HXR set to digitize 1.5 s of data- giving longer store times and larger data sets.
ICRF set to go at 1.45 s.

Fault on segment 1, RINTs ok third harmonic seems to be the culprit. Second pulse through ok. Lots HXR and ECE signal from the low density nl04 ~3.2.

Antenna looks ok on LH camera.
Apr 20 2006 09:43:23:767AM1060420003John LiptacUsing 90 degree CD phasing
50kW/klystron
Two 50 ms pulses with a 50 ms spacing at 1.2 s.

Keep loosing first segment. Go to three segments and plan on getting two. Lots of hards see we can bring them down about.
Apr 20 2006 09:53:29:877AM1060420004John LiptacUsing 90 degree CD phasing
55kW/klystron
Three 60 ms pulses with a 40 ms spacing at 1.1 s.

Got all three this time. Periodic oscillation returns on klystron 4.


Apr 20 2006 10:07:48:313AM1060420005John LiptacUsing 90 degree CD phasing
60kW/klystron
Three 70 ms pulses with a 30 ms spacing at 1.1 s.

Periodic oscillation on klystron 4 segment 1 only.


Apr 20 2006 10:22:39:093AM1060420006John LiptacUsing 90 degree CD phasing
65kW/klystron
Three 80 ms pulses with a 20 ms spacing at 1.1 s.

Klystron 4 set to 50kW. Got all three, tremendous HXR and ECE signal. Lots of pile up and creation of runaways. No oscillation on 4.


Apr 20 2006 10:33:16:173AM1060420007John LiptacUsing 90 degree CD phasing
70kW/klystron
Three 90 ms pulses with a 10 ms spacing at 1.1 s.

Klystron 4 set to 50kW. Pulses are starting to fill in.




Apr 20 2006 10:48:17:783AM1060420008John LiptacUsing 90 degree CD phasing
75kW/klystron
Three 100 ms pulses with a 0 ms spacing at 1.1 s.

Klystron 4 set to 50kW.
Lost first 40 ms on first pulse, began on second restrike attempt and then ran well.


Apr 20 2006 11:17:18:430AM1060420009John LiptacUsing 90 degree CD phasing
75kW/klystron
Four 100 ms pulses with a 0 ms spacing at 1.0 s.

Klystron 4 set to 50kW. Bad oscillation, and likely arc on 4, reduce power. Faulted at end. No change on current or loop voltage. 3rd harmonic might have actually worked.



Apr 20 2006 11:12:54:563AM1060420010John LiptacUsing 90 degree CD phasing
75kW/klystron
Four 100 ms pulses with a 0 ms spacing at 1.0 s.

Klystron 4 set to 40kW. Oscillation gone on 4. Faulted at beginning. No change on current or loop voltage

Cell access to go to 90 CCD.
Apr 20 2006 12:52:24:140PM1060420011John LiptacUsing 90 degree CCD phasing
40kW/klystron
Four 20 ms pulses with a 80 ms spacing at 1.0 s.
Klystron 4 will be kept at 40kW throughout

Lost pulse number 4. How bout some current! Increase power and pulse length and try to drive more.
Apr 20 2006 12:20:57:077PM1060420012John LiptacUsing 90 degree CCD phasing
50kW/klystron
Four 40 ms pulses with a 60 ms spacing at 1.0 s.

More current! Increase power and pulse length and try to drive more, and match results from the start of the run.
Apr 20 2006 12:27:45:250PM1060420013John LiptacUsing 90 degree CCD phasing
55kW/klystron
Four 50 ms pulses with a 50 ms spacing at 1.0 s.

Runaways to start with. Fault on the start of segment 3.
Apr 20 2006 12:45:21:953PM1060420014John LiptacUsing 90 degree CCD phasing
60kW/klystron
Four 60 ms pulses with a 40 ms spacing at 1.0 s.

Faults on segments 1, 2, and 4. Try running pulses together to avoid some of these trips.
Apr 20 2006 01:17:24:250PM1060420015John LiptacUsing 90 degree CCD phasing
60kW/klystron
Four 100 ms pulses with a 0 ms spacing at 1.0 s.

Timing issue on klystron 4 causes fault.


Apr 20 2006 01:29:25:047PM1060420016John LiptacUsing 90 degree CCD phasing
65kW/klystron
Four 100 ms pulses with a 0 ms spacing at 1.0 s.

Two faults to start. Oscillation on klystron 5. Go down in power and change phase.


Apr 20 2006 01:36:49:827PM1060420017John LiptacUsing 120 degree CCD phasing
50kW/klystron
Four 100 ms pulses with a 0 ms spacing at 1.0 s.

Faults on first four tries.
Apr 20 2006 01:54:14:687PM1060420018John LiptacUsing 120 degree CCD phasing
60kW/klystron
Four 100 ms pulses with a 0 ms spacing at 1.0 s.

60 kW klystron can compare directly with shot 15. Great result got all 4 segments.
Apr 20 2006 02:09:10:327PM1060420019John LiptacUsing 60 degree CCD phasing
50kW/klystron
Four 100 ms pulses with a 0 ms spacing at 1.0 s.

Ran well, one fault at start up. Go to 60 kW/klystron
Apr 20 2006 02:19:48:983PM1060420020John LiptacUsing 60 degree CCD phasing
60kW/klystron
Four 100 ms pulses with a 0 ms spacing at 1.0 s.

Faulted twice, Once on RINT3.

Apr 20 2006 02:35:33:373PM1060420021John Liptac6.5 T, Try to get better penetration.

Using 60 degree CCD phasing
60kW/klystron
Four 100 ms pulses with a 0 ms spacing at 1.0 s.

More of an effect. Go back to 90.



Apr 20 2006 02:44:25:187PM1060420022John Liptac6.5 T.

Using 90 degree CCD phasing
60kW/klystron
Four 100 ms pulses with a 0 ms spacing at 1.0 s.

No LH faulted out 6 times and gave up.



Apr 20 2006 02:59:12:640PM1060420023John Liptac6.5 T.

Using 90 degree CCD phasing
60kW/klystron
Four 100 ms pulses with a 0 ms spacing at 1.0 s.

No faults ran through all segments.



Apr 20 2006 03:12:37:873PM1060420024John Liptac6.5 T.

Using 90 degree CCD phasing
60-75 kW/klystron Ramp
Four 100 ms pulses with a 0 ms spacing at 1.0 s.
Klystron 4 set at 40 kW.

3 faults on startup and then went.

Apr 20 2006 03:25:37:843PM1060420025John Liptac6.5 T.

Using 90 degree CCD phasing
65-80 kW/klystron Ramp
Four 100 ms pulses with a 0 ms spacing at 1.0 s.
Klystron 4 set at 40 kW.

Fault on first two segments

Apr 20 2006 03:44:10:687PM1060420026John Liptac6.5 T.

Using 90 degree CCD phasing
70-85 kW/klystron Ramp
Four 100 ms pulses with a 0 ms spacing at 1.0 s.
Klystron 4 set at 40 kW.

Fault first segment. Periodic oscillation on klystron 1.

Apr 20 2006 03:59:26:280PM1060420027John Liptac6.5 T.

Using 90 degree CCD phasing
70-85 kW/klystron Ramp
Four 100 ms pulses with a 0 ms spacing at 1.0 s.
Klystron 4 set at 40 kW.
Klystron 1 set to 60 kW..

No problem on 1 this time and got all segments.



Apr 20 2006 04:18:03:827PM1060420028John Liptac6.5 T.

Using 90 degree CCD phasing
70-85 kW/klystron Ramp
Four 100 ms pulses with a 0 ms spacing at 1.0 s.
Klystron 4 set at 40 kW.
Klystron 1 set to 60 kW.

Increase density slightly to lower HXR signal and reduce pile up.

Got all segments. Density only slightly higher would like nl04 of about 0.5.

Apr 20 2006 04:36:16:983PM1060420029John Liptac6.5 T.

Using 90 degree CCD phasing
70-85 kW/klystron Ramp
Four 100 ms pulses with a 0 ms spacing at 1.0 s.
Klystron 4 set at 40 kW.
Klystron 1 set to 60 kW.

Increase density slightly to lower HXR signal and reduce pile up.

Got all segments.

Apr 20 2006 04:42:42:060PM1060420030John Liptac6.5 T.

Using 90 degree CCD phasing
70-85 kW/klystron Ramp
Four 100 ms pulses with a 0 ms spacing at 1.0 s.
Klystron 4 set at 40 kW.
Klystron 1 set to 60 kW.

Increase density slightly to lower HXR signal and reduce pile up.

Cart 3 into loads to try and check phasing.

Not dramatically different from the previous shot.
Apr 20 2006 04:45:39:513PM1060420030John Liptac6.5 T.

Using 90 degree CCD phasing
70-85 kW/klystron Ramp
Four 100 ms pulses with a 0 ms spacing at 1.0 s.
Klystron 4 set at 40 kW.
Klystron 1 set to 60 kW.

Increase density slightly to lower HXR signal and reduce pile up.

Cart 3 into loads to try and check phasing.

Not dramatically different from the previous shot. Go back to low density and try and check again
Apr 20 2006 04:55:28:797PM1060420031John Liptac6.5 T.

Using 90 degree CCD phasing
70-85 kW/klystron Ramp
Four 100 ms pulses with a 0 ms spacing at 1.0 s.
Klystron 4 set at 40 kW.
Klystron 1 set to 60 kW.

Cart 3 into loads to try and check phasing.

Tried to match density from shot 27. Three faults to start.

Physics Operator Comments
Apr 20 2006 09:17:22:470AM1060420001Ron ParkerShot 1 ran as programmed.
Apr 20 2006 09:26:36:597AM1060420002Ron ParkerShot 002 was a dud. Sparker current much lower than yesterday.
Apr 20 2006 10:38:50:173AM1060420003Ron ParkerShot 3 ran without changes. Rf pulse at 50 ms, ~ 50 kW per klystron at FINT.
Apr 20 2006 10:39:11:017AM1060420004Ron ParkerShot 4 ran OK
Apr 20 2006 10:38:25:407AM1060420005Ron ParkerShot 5 was OK
Apr 20 2006 10:21:21:423AM1060420006Ron ParkerShot 6 ran ran OK. No problems shince loading 1060310024
Apr 20 2006 10:37:59:847AM1060420007Ron ParkerShot 7 ran OK. Power up to 60-70 kW per klystron.
Apr 20 2006 10:40:54:143AM1060420008Ron ParkerShot 8 ran OK, Continuous RF for 250 ms.
Apr 20 2006 11:08:17:360AM1060420009Steve Wolfe
Shot#10: Wolfe filling in for Parker as physop while he's at class.
No PCS changes for this shot.
Plasma.

Next: Cell access to change mech. phase setting

Apr 20 2006 12:06:21:903PM1060420011Steve Wolfe
Shot#11: LH phase has been reversed. Pulse train set back to 
wimpy little 20msec blips.
No PCS changes. 

plasma, lots of late hard xrays. Serious blips on Te8
Looks like current drive on loop voltage and Ip traces
at 1.0, 1.1, 1.2

Apr 20 2006 12:14:39:233PM1060420012Steve Wolfe
Shot#12: No PCS changes, increasing pulse width on LH pulses
plasma. Four LH pulses. Look at that loop voltage change!

Apr 20 2006 12:28:12:657PM1060420013Steve Wolfe
Shot#13: No PCS changes
Plasma had runaways at the beginning. 
50msec pulses, fault on the third one. 
Nice response on Vl and Ip

Apr 20 2006 12:32:14:500PM1060420013Steve Wolfe
Shot#14: No PCS changes
Ron's back.

Apr 20 2006 12:42:53:327PM1060420014Ron ParkerShot 14 went off OK.
Apr 20 2006 01:39:38:983PM1060420015Ron ParkerShot 15 ran well.
Apr 20 2006 01:39:51:517PM1060420016Ron ParkerShot 17 ran OK.
Apr 20 2006 01:39:26:890PM1060420017Ron ParkerShot 16 ran well.
Apr 20 2006 01:53:16:483PM1060420018Ron ParkerShot 18 ran well.
Apr 20 2006 02:06:06:187PM1060420019Ron Parkershot 19 was OK.
Apr 20 2006 02:23:26:437PM1060420020Ron ParkerShot 20 ran. Next: raise field by 20%, 5.4 T to 6.5 T
Apr 20 2006 02:45:14:060PM1060420021Ron ParkerShot 21 went off well.
Apr 20 2006 02:44:30:483PM1060420022Ron ParkerShot 22 went off well, but no RF.
Apr 20 2006 03:49:15:123PM1060420023Ron ParkerShot 23 was OK.
Apr 20 2006 03:50:08:013PM1060420024Ron ParkerShot 24 was fine.
Apr 20 2006 03:50:29:373PM1060420025Ron ParkerShot 25 was good.
Apr 20 2006 03:47:50:390PM1060420026Ron ParkerShot 26 went off OK.
Apr 20 2006 04:00:53:110PM1060420027Ron ParkerShot 27 was good. All klystrons around 80 kW, except V1 and V4.
Apr 20 2006 04:04:50:437PM1060420027Ron ParkerShot 27 went off OK. Next: set density to ne_l(4) to 5e19 cm-2
Apr 20 2006 04:19:09:077PM1060420028Ron ParkerShot 28 was good. Next increase programmed density to 6 cm-2 on ne_l4.

Apr 20 2006 04:29:32:220PM1060420029Ron ParkerShot 29 ran as programmed, density higher, less effect of current drive.
Apr 20 2006 04:50:44:937PM1060420030Ron ParkerShot 30 OK. Cart 3 off. similar change in voltage, but somewhat higher density.
Apr 20 2006 05:02:25:593PM1060420031Ron ParkerShot 31, the final shot of today's run, was good.

Engineering Operator Comments
ShotTimeTypeStatusComment
108:59:41:050AMPlasmaOk
209:16:00:440AMPlasmaOk
309:28:28:097AMPlasmaOk
409:43:42:940AMPlasmaOk
509:59:08:923AMPlasmaOk
610:11:35:377AMPlasmaOk
710:24:34:610AMPlasmaOk
810:37:03:673AMPlasmaOk
910:49:29:830AMPlasmaOk
1011:05:45:110AMPlasmaOk
1111:55:59:593AMPlasmaOk
1212:10:35:000PMPlasmaOk
1312:23:04:030PMPlasmaOk
1412:35:37:450PMPlasmaOk
1512:51:46:187PMPlasmaOk
1601:20:40:610PMPlasmaOk
1701:33:18:390PMPlasmaOk
1801:45:55:420PMPlasmaOk
1902:00:44:297PMPlasmaOk
2002:14:06:453PMPlasmaOk
2102:27:47:953PMPlasmaOk
2202:40:39:047PMPlasmaOk
2302:54:52:623PMPlasmaOk
2403:07:41:407PMPlasmaOk
2503:21:35:263PMPlasmaOk
2603:38:15:390PMPlasmaOk
2703:55:47:030PMPlasmaOk
2804:09:40:780PMPlasmaOk
2904:23:37:797PMPlasmaOk
3004:36:41:810PMPlasmaOk
3104:50:07:513PMPlasmaOk