Alcator C-Mod Run 1060511 Information

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Miniproposals

Operators
Session leader(s):
Physics operator(s):Ron Parker,Robert Granetz,Ron Parker
Engineering operator(s):Bill Cochran,Ed Fitzgerald,Gary Dekow

Engineering Operator Run Comment
MP#418 LH Coupling studies SL: Liptac/Parker PO: Parker

Session Leader Plans
Entered: May 11 2006 07:09:48:460AM
Author: John Liptac
Run Plan for 1060511

Goals:
1. Complete approximate phase coupling study.
2. Optimize plasma elongation for coupling.
3. Test full CPS
4. LHCD experiments varying phase, density, field. ICRF power will also be used to increase the temperature.

Plasma Conditions: Load shot number 1060406009, low density L-mode with nl04 ~0.4e20, 700 kA plasma current, 5.4 T magnetic field. Later in the day add up to 2 MW of ICRF power.

Initial LH setup: Begin with the phase shifters set for 90 degree CD phasing with launcher at a position of 1615 counts ~3 mm behind limiter. CPS bypassed. 20 kW/klystron.


Physics Operators Plans
Entered: May 10 2006 05:59:52:617PM
Author: Ron Parker
Physop Plan and Engineering Setup for Thursday, May 11


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

ECDC overnight in D2 at 2.e-4 Torr

Power systems as on 1060420001
A-coil configuration: normal [+Dtop -Dbot -Jtop +Jbot] and enabled.
C-coil Start=0.3sec, Invert=2.0sec

ICRF: Need 2 MW reliable and long pulse from shot 19 on

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)


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

Run Plan: We will test the CPS. Assuming it works satisfactorily we will try to raise LH power with optimal CD phasing. We'll begin with additional coupling studies, then move to high power for CD.

Session Leader Summaries
Entered: May 11 2006 05:16:50:913PM
Author: John Liptac
The approximate phase coupling study was completed using 20 different phases per shot at three positions behind the limiter. The lowest reflection coefficient obtained was about 11%. A significant improvement over previous results. The probe density measured at the grill seemed to be more uniform than it has been in the past.

After the coupling experiments were completed, the CPS system was eneabled and tested. It was found that a number of circuits, 14/60, had to be bypassed in order to run. The power level was then increased for current drive experiments. The LH system seemed to operate best when used for continuous segments, where the klystron power does not have to switch on and off. This indicates that the best way to bring the power level up is to run continuously for the desired pulse length and while increasing the klystron power from shot to shot.

LHCD data using non-compound spectra was gathered at a variety of phases, densities, and powers. The milestone of coupling 500 kW of LH power was first reached on shot 16. Shot 17 had over 500 kW coupled with a 6.3 T magnetic field.

Combining LH with ICRF proved difficult due to pickup from the ICRF system on the CPS sytem. This will need to be addressed before the two systems can run simultaneously. The end of the run suffered from duds and fizzles.


Physics Operator Summaries
Entered: May 11 2006 05:25:49:947PM
Author: Ron Parker
Today's run was devoted to the Lower Hybrid experiments.

The machine ran at 700 kA all day, with densities between 0.3 and 0.5 e20 m-2.

The machine ran reasonably well until shot 23, which fizzled for no apparent reason. Then followed a full term shot,followed by another fizzle, then a dud due to misfunction of power supply waveforms, then a fizzle. It is strange that after 22 shots that ran perfectly, the machine became very difficult to run, with several fizzles in the last shots. This seems to be a pattern, at least with this operator.

The CPS was a partial succes, but 14 channels had to be disabled to prevent spurious trips. The ICRF also causes trips; this hopefully will be fixed by installing filters in the same way that fixed the RINT-FINT protection circuitry.

Scorecard: 23 full length plasmas, 3 fizzles toward end of run, and 2 duds, one due to TF PLC fault, the other due to PF Power Supply fault.

Session Leader Comments
May 11 2006 10:01:51:883AM1060511001John LiptacBegin with approximate phase coupling study.

20 segments, 60,90,120,150,180 and repeat CD phasing.
20 kW/klystron.
Grill position at 1615 counts.
CPS bypassed.

Got all 20 segments. nl04 pretty low 2e19. Made a lot of hard x-rays.

Repeat but with about twice the density.
May 11 2006 10:00:20:007AM1060511002John LiptacApproximate phase coupling study.

20 segments, 60,90,120,150,180 and repeat CD phasing.
20 kW/klystron.
Grill position at 1615 counts.
CPS bypassed.

Got all 20 segments! Fabulous! nl04 ~ 0.4e20

Cell access to move the launcher in and check the LH camera.
May 11 2006 09:57:45:727AM1060511003John LiptacApproximate phase coupling study.

20 segments, 60,90,120,150,180 and repeat CD phasing.
20 kW/klystron.
Grill position at 1600 counts.
CPS bypassed.

Got all 20 segments! nl04 ~ 0.3e20 lowered the density at the probes by ~50% try to increase density slightly and repeat. Reflection coef seemed to go down a little even with the lower density.

May 11 2006 09:56:58:180AM1060511004John LiptacApproximate phase coupling study.

20 segments, 60,90,120,150,180 and repeat CD phasing.
20 kW/klystron.
Grill position at 1600 counts.
CPS bypassed.

Got all 20 segments! nl04 ~ 0.4e20. Can go in and move launcher to 1585.


May 11 2006 10:14:52:930AM1060511005John LiptacApproximate phase coupling study.

20 segments, 60,90,120,150,180 and repeat CD phasing.
20 kW/klystron.
Grill position at 1585 counts.
CPS bypassed.

Got all 20 segments. nl04 ~0.33 a bit too low, density didn't change much on the probes. Try again with a little higher density.

May 11 2006 10:28:41:710AM1060511006John LiptacApproximate phase coupling study.

20 segments, 60,90,120,150,180 and repeat CD phasing.
20 kW/klystron.
Grill position at 1585 counts.
CPS bypassed.

Got all 20 segments. nl04 ~0.5, Best reflection coef ~11%

Move on to increasing the power for current drive experiments.
May 11 2006 12:00:24:490PM1060511007John LiptacBring up LH power for current drive experiments and CPS testing.

3 segments, 120,90,60 CD phasing. 133 ms 50% duty cycle
40-60 kW ramp.
Grill position at 1585 counts.
CPS enabled.

No LH power on any segment, faulted out each time.

Need cell access to bypass individual circuits and give JT a chance to get the LH camera working. 14 circuits bypassed.
May 11 2006 11:51:41:680AM1060511008John LiptacBring up LH power for current drive experiments and CPS testing.

3 segments, 120,90,60 CD phasing. 133 ms 50% duty cycle
40-60 kW ramp.
Grill position at 1585 counts.
CPS enabled.
Got three segments, faulted on the start of segments 2 and 3. The loop voltage decreases slightly during each segment.
May 11 2006 12:08:24:430PM1060511009John LiptacBring up LH power for current drive experiments and CPS testing.

3 segments, 120,90,60 CD phasing. 133 ms 100% duty cycle
40-60 kW ramp.
Grill position at 1585 counts.
CPS enabled.

Turining off and on is harder for the system, because of transients. Stretch pulses all together to go for 100% duty cycle.

No faults! Increase power.

May 11 2006 12:31:09:790PM1060511010John LiptacBring up LH power for current drive experiments and CPS testing.

3 segments, 120,90,60 CD phasing. 133 ms 100% duty cycle
50-70 kW ramp.
Grill position at 1585 counts.
CPS enabled.

Fault on segment 2, picked up on retry. Continue to raise power.

May 11 2006 12:50:39:197PM1060511011John LiptacBring up LH power for current drive experiments and CPS testing.

3 segments, 120,90,60 CD phasing. 133 ms 100% duty cycle
50-70 kW ramp.
Grill position at 1585 counts.
CPS enabled.

No faults.

May 11 2006 01:09:57:693PM1060511012John LiptacBring up LH power for current drive experiments and CPS testing.

3 segments, 120,90,60 CD phasing. 133 ms 100% duty cycle
60-80 kW ramp.
Grill position at 1585 counts.
CPS enabled.

Fault maybe from column 21.

Two faults, one failed retry.

May 11 2006 01:22:31:617PM1060511013John LiptacBring up LH power for current drive experiments and CPS testing.

3 segments, 120,90,60 CD phasing. 133 ms 100% duty cycle
70-90 kW/klystron.
Grill position at 1585 counts.
CPS enabled.

Klystron 11 fixed at 60 kW.


May 11 2006 01:26:49:523PM1060511014John LiptacBring up LH power for current drive experiments and CPS testing.

3 segments, 120,90,60 CD phasing. 133 ms 100% duty cycle
90 kW/klystron.
Grill position at 1585 counts.
CPS enabled.

Klystron 11 fixed at 60 kW.

Lost all of the first segment. Density went high.
May 11 2006 01:54:34:007PM1060511015John LiptacBring up LH power for current drive experiments and CPS testing.

3 segments, 90,90,90 CD phasing. 133 ms 100% duty cycle
90 kW/klystron.
Grill position at 1585 counts.
CPS enabled.

Klystron 11 fixed at 60 kW.

Almost the milestone of 500 kW. Try for a little more.
May 11 2006 02:14:32:633PM1060511016John LiptacBring up LH power for current drive experiments and CPS testing.

3 segments, 90,90,90 CD phasing. 133 ms 100% duty cycle
100 kW/klystron.
Grill position at 1585 counts.
CPS enabled.
Klystron 7 fixed at 90 kW.
Klystron 11 fixed at 70 kW.
Klystron 12 fixed at 80 kW.

Trophy shot! 500 kW coupled milestone met.

No faults 550-525 kW for 400ms.
May 11 2006 02:37:13:087PM1060511017John Liptac6.3 T.
3 segments, 90,90,90 CD phasing. 133 ms 100% duty cycle
100 kW/klystron.
Grill position at 1585 counts.
CPS enabled.
Klystron 7 fixed at 90 kW.
Klystron 11 fixed at 60 kW.
Klystron 12 fixed at 80 kW.

No faults, >500 kW coupled for 400 ms.
May 11 2006 03:10:12:990PM1060511020John Liptac5.4 T, 1 MW ICRF

3 segments, 90,90,90 CD phasing. 133 ms 100% duty cycle
100 kW/klystron.
Grill position at 1585 counts.
CPS enabled.
Klystron 7 fixed at 90 kW.
Klystron 11 fixed at 60 kW.
Klystron 12 fixed at 80 kW.

ICRF 0.65 to 1.1 s, asking for 1 MW from D.

ICRF worked, but faulted out LH for the whole shot.
May 11 2006 03:26:50:757PM1060511021John Liptac5.4 T, 1 MW ICRF

3 segments, 90,90,90 CD phasing. 133 ms 100% duty cycle
100 kW/klystron.
Grill position at 1585 counts.
CPS enabled.
Klystron 7 fixed at 90 kW.
Klystron 11 fixed at 60 kW.
Klystron 12 fixed at 80 kW.

ICRF 0.65 to 1.1 s, asking for 1 MW from J.

1 MW ICRF and 5 ms of LH power. Pretty poor.
May 11 2006 03:58:01:443PM1060511022John Liptac5.4 T, No ICRF

3 segments, 60,90,120 CD phasing. 133 ms 100% duty cycle
70 kW/klystron.
Grill position at 1585 counts.
CPS enabled.

Klystron 11 fixed at 60 kW.

Got good phase scan data. Would have been a little better if density was flatter, but should be ok. Cell access to bypass more CPS circuits and run with ICRF. If it doesn't help, then return to this shot and try to get more phase data.
May 11 2006 04:23:27:867PM1060511024John Liptac5.4 T, 1 MW ICRF

3 segments, 90,90,90 CD phasing. 133 ms 100% duty cycle
100 kW/klystron.
Grill position at 1585 counts.
CPS bypassed.
Klystron 7 90 kW fixed.
Klystron 11 60 kW fixed.
Klystron 12 80 kW fixed.

ICRF 0.65 to 1.1 s, asking for 1 MW from J.

Not much LH power again, still faulted out.
May 11 2006 04:43:17:600PM1060511026John Liptac5.4 T, 1 MW ICRF

3 segments, 90,90,90 CD phasing. 133 ms 100% duty cycle
50 kW/klystron.
Grill position at 1585 counts.
CPS bypassed.


ICRF 0.65 to 1.1 s, asking for 1 MW from J. LH breaker opened before shot, no LH power.


Physics Operator Comments
May 11 2006 09:09:31:883AM1060511001Ron ParkerThursday, 11 May Lower Hybrid Run

No overnight ECDC. otherwise machine ready for first shot at 9:00

First shot went off well, lots of hards.

Next: increase density.
May 11 2006 09:34:02:117AM1060511002Ron ParkerShot 2 was good, density stabilized at nl(04)=0.4 m-2.

Next:same shot, move LH coupler in ~1.5 mm back from LH limiter. Cell access, also to fix camera.

Touch up pulsed gas to try to reduce early runaway production.
May 11 2006 09:44:44:350AM1060511003Ron ParkerShot 3 ran OK, but density dropped to ~ 0.3e20 m-2.

For next shot, set density at 0.45e20 m-2.
May 11 2006 10:08:13:087AM1060511004Ron ParkerShot 4 ran well. Density closer to 4.0e19 m-2.

Next: Move coupler in, ~flush with limiter. Same shot. Cell access.
May 11 2006 10:14:58:240AM1060511005Ron ParkerShot 5 ram well, density sagged again probably due to longer time between shots because of cell access.

Next: Repeat.
May 11 2006 10:39:26:053AM1060511006Ron ParkerShot 6 ran well, density came up to 0.5e20 m-2.

Next: Begin increasing LH power, check out of CPS.


May 11 2006 10:41:30:023AM1060511007Ron ParkerShot 7 ran OK, density down. But LH protection inhibited LH power.
May 11 2006 10:55:15:210AM1060511008Robert GranetzI'm substituting as physics operator for Ron for the next hour or so while
he goes to teach a class.

However, there are some technical issues with the LH system that are being
worked on right now, and that may require a cell access, so it might be a
while before we have another shot.
May 11 2006 11:41:45:273AM1060511008Robert Granetz11:40 Finally ready to try for shot 8 after a long cell access.
May 11 2006 11:48:34:070AM1060511008Robert GranetzShot 08 -- Plasma. Good shot. 0.7 MA, 5.4 T, nl_04=0.4e20 m-2.

Next shot: no PCS changes.
May 11 2006 12:04:54:477PM1060511009Robert GranetzShot 09 -- Plasma. Good shot. 0.7 MA, 5.4 T, nl_04=0.4-0.5e20 m-2.

Next shot: no PCS changes.
May 11 2006 12:17:06:740PM1060511010Robert GranetzShot 10 -- Plasma. Good shot. 0.7 MA, 5.4 T, nl_04=0.4e20 m-2

Next shot: no PCS changes.
May 11 2006 12:23:39:650PM1060511010Robert GranetzRon has returned, so he's taking over again as physop, starting
with the next shot (shot 11).
May 11 2006 12:27:01:540PM1060511010Ron ParkerNo change for shot 11. Short delay to fix logbook problem.
May 11 2006 12:49:07:540PM1060511011Ron ParkerShot 11 looked good, no LH trips.
May 11 2006 01:21:10:650PM1060511012Ron ParkerShot 12 ran well. No changes for next shot.
May 11 2006 01:20:37:460PM1060511013Ron ParkerShot 13 ran well. Good LH power > 80 kW/klystron, except #11.

May 11 2006 01:50:25:087PM1060511014Ron ParkerShot 14 ran well, LH coupled power reached 500 kW, but for short duration.

Density was a bit high -- 0.5e20 m-2.
May 11 2006 01:51:07:383PM1060511015Ron ParkerShot 15 ran well. lower density. Loop voltage minimum ~ 0.33 V early in LH pulse.
May 11 2006 02:18:38:587PM1060511016Ron ParkerShot 16 ran well, LH power over 500 kW coupled.

Next: 6.3 T
May 11 2006 02:42:50:163PM1060511017Ron ParkerShot 17 ran well. RF pulse > 500 kW.
May 11 2006 02:41:29:087PM1060511018Ron ParkerNo TF, no nothing - the well-known PLC problem
May 11 2006 03:03:23:367PM1060511019Ron ParkerShot 19 ran OK. Density is not being well regulated by feedback.
May 11 2006 03:33:03:477PM1060511020Ron ParkerShot 20 ran OK, first attempt to run ICRF with LH. ICRF pickup tripped LH CPS, no LH pulses.
May 11 2006 03:33:17:430PM1060511021Ron ParkerShot 21 attempted to combine LH with ICRF from J-port. ICRF still cuts out LH protection. There will be a ~ 20-30 minute delay while CPS circuits are disconnected. Oops, change in plan -- we will due more phase scans before disconnecting CPS circuits.

May 11 2006 03:57:47:867PM1060511022Ron ParkerShot 22 ran well, 3 RF phases @ ~ 60+ kW/klstron.

Next: Try ICRF again (J-port) with CPS disconnected.
May 11 2006 04:05:35:023PM1060511023Ron ParkerFizzle -caused by opening beam gate valve?
May 11 2006 04:18:14:523PM1060511024Ron ParkerShot 24 ran -- no density control! -- but ICRF still tripped out CPS, even though many channels were bypassed. Next: bypass RINT-FINT protective circuitry.
May 11 2006 04:39:04:447PM1060511025Ron ParkerAnother fizzle, no beam valve opening.
May 11 2006 04:50:57:930PM1060511026Ron ParkerShot went, but no LHRF --- breaker tripped before shot.

Try again for last shot. Lower EF4 current to -1350 from -1335.
May 11 2006 05:04:16:210PM1060511027Ron ParkerShot was a dud -- program for EF supplies did not run properly, no field null.

Try one more shot.

Engineering Operator Comments
ShotTimeTypeStatusComment
109:01:51:303AMPlasmaOk
209:16:05:273AMPlasmaOk
309:35:29:553AMPlasmaOk
409:48:32:820AMPlasmaOk
510:07:34:383AMPlasmaOk
610:22:04:240AMPlasmaOk
710:35:39:100AMPlasmaOk
811:43:15:133AMPlasmaOk
911:59:49:693AMPlasmaOk
1012:12:20:603PMPlasmaOk
1112:41:23:507PMPlasmaOk
1212:53:57:757PMPlasmaOk
1301:09:14:710PMPlasmaOk
1401:21:38:227PMPlasmaOk
1501:39:58:443PMPlasmaOk
1602:03:44:210PMPlasmaOk
1702:18:46:897PMPlasmaOk
1802:36:22:257PMPlasmaBadNo TF
1902:49:37:087PMPlasmaOk
2003:05:28:647PMPlasmaOk
2103:18:04:897PMPlasmaOk
2203:34:03:913PMPlasmaOk
2303:59:41:383PMPlasmaOk
2404:13:26:600PMPlasmaOk
2504:26:13:117PMPlasmaOk
2604:38:38:900PMPlasmaOk
2704:52:07:210PMPlasmaBadDPCS Problem
2805:13:04:710PMPlasmaOk