Miniproposals

Miniproposal: 059 Date Filed: 6/6/1994 Title: ICRF Heating (PRF>1 MW) First Author: Yuichi Takase Session Leader: Steve Golovato (shots 1-27)

Engineering Operator Run Comment

rf heating Golavato/takase bertolino/fairfax

Session Leader Plans

Physics Operators Plans

Session Leader Summaries

Entered: Jul 7 2004 03:49:11:197PM

Author: To Be Determined

Session Leader Summary - Run 940616 SL - Golovato PO - Goetz EO - Bertolino/Fairfax Goals - ICRF heating run 1) Complete density scan with limited plasmas, particularly going to higher densities at 800ka. 2) Current scan with limited plasmas. 3) Edge profiles with and without rf using fast scanning. 4) Heating of diverted plasmas. The run was successful although all goals were not met. We didn't get to goals 3 and 4, which will be left to next Wednesday's run. However we did achieve goals 1 and 2. We has trouble with density control for the first shots because of the plenum pressure (see phys op summary). Then we had trouble raising the density with the plasma was limited on the divertor nose (shots 4 and 5). We got an elmy H-mode on shot 4 during the entire rf pulse accept at interrupts. The nl was about 6.e19. By moving the plasma out by 5 mm and reducing the elongation to about 1,3-1.4, we got inner wall limited plasmas and nl_04=1.e20 (shots 6 and 7). On shot 8, we added a lot of gas and got a strange relaxation oscillation in the density and H_alpha that was very H-mode-like, i.e., the density went up when the H_alpha went down. It wasn't synched to the sawteeth. We have previously seen locked modes under similar conditions near the operational, if not the Greenwald, density limit using gas puffing. This often led to a disruption, though not in this case. We were still having trouble tuning for densities above 1.e20 and did not have rf for shots 6-8, 12, 15-16. Shot 12 was another like shot 8. Shots 10, 11,and 13 had a little lower gas puffing and the density stalled at .5-.6 sec and didn't get above 1.e20. To get controlled higher density, we used inner wall puffing from the capilliary system for shots 15-21. This allowed us to make plasmas with flat density above 1.e20 and we were able to tune to these plasmas and get high power in on shots 17,18, and 21. We then went to the current scan. Shots 18-19 were at higher current, with shot 19 disrupting at 950 ka, though rather slowly and stationary since the elongation was low. A better current scan was achieved on shots 22-26 with currents from 400-1000 ka. The heating looks particularly good at low current, where the rf provides much more than the Ohmic power. A 250 ka shot failed on the last shot. The loading can be very high at high density, we saw 20-40 Ohms, though the highest density we matched at high power was 20 Ohms. We need to move up slowly in density so we can track the tuning. Unfortunately we didn't have sufficient control of the density for much of the run to do this. The good rf-heated shots were: 2,4,9,11,13,14,17,18,21-26. The density scan (nl_04=6-12e19) at 800 ka included: 2,4,9,11,13,14,17,21-23. The currents other than 800 ka were: 18(900), 24(600), 25(400), 26(1000). Good shots without high power rf were: 5-7, 15,16. Shot accounting: 25 plasmas (2 early disruptions) 1 fizzle (after 950 ka disruption)

Physics Operator Summaries

Entered: Jul 7 2004 04:36:51:910PM

Author: To Be Determined

Physics operator summary for 940616 EO: Bertolino/Fairfax PO: Goetz SL: Golovato Run 940616 was in support of Mini-Proposal #059 - RF Heating at > 1 MW. This run started with limiter discharges and a density scan followed by a current scan were performed. Shot 940608003 was the shot loaded to be the starting shot. The current flat-top was extended to 1.0 sec to allow for extra time to obtain before and after RF pulse data. A good day to be an operator. Limited discharges with a current and density scan are not too taxing on the brain-box. As usual, controlling the density for limited discharges is difficult. The disruption today may have been caused by a runaway density. No change was made from the previous shot and the density kept on climbing. Possibly, MHD activity affected the fueling efficiency. The divertor gas puffing system was used to increase the line- averaged density to ~2e20 for part of the density scan. The elongation was lowered early in the run using the IC_EF1's to try and keep the plasma off the inner nose. Outer gap control was accomplished using RCUR programming. At the lower currents of the current scan, the outer gap was too large, but only one shot at each current was taken, so no corrective behavior was attempted. Engineering today: Cooling troubles limited the shot cycle to ~20 minutes between shots. It appears that the sump filter is beginning to become plugged. Increasing the pump speed helped the situation. The pressure in the plenum used to fuel the plasma was approximately 8PSIA when the run started. This led to very low densities for the first few shots because the gas programming was for a higher driving pressure. The plenum was refilled and things returned to normal. Operators should check to make sure the plenum pressure is where they want it. Scorecard: 27 shots = 26 plasmas + 1 fizzle Shot summary for Run 940616 Reload of 940608003 Changes: extend current flat-top to 1.0sec extend IP controller gain switch to 1.0sec extend RCUR waveform to 1.0sec ( @0.66 ) remove puff from PULSE_GAS_3 and extend pulse Shot change result ____ _____ ______ 1 fiducial 940608003 plasma 2 see above plasma 3 increase PULSE_GAS_3 from 0.4 to 0.9sec plasma 4 raise pressure in A_SIDE plenum to 15.5 PSIA; drop PULSE_GAS_3 to 40V plasma 5 PULSE_GAS_3 to 44V from 0.4 to 0.9 sec; RCUR to 0.665 from 0.6 to 1.0sec plasma 6 IC_EF1's to 3000A from 0.6 to 1.2sec; PULSE_GAS_3 to 48V from 0.4 to 0.9sec; IC_EF4 flattop extended to 0.7sec plasma 7 take 2V off PULSE_GAS_3 after 0.7sec plasma 8 PULSE_GAS_1 second puff to 0.65 (90V x .015sec); ramp down PULSE_GAS_3 from 0.4 to 1.0 plasma 9 PULSE_GAS_3 dropped to 42V @ 0.4 and 32V @ .92sec plasma 10 PULSE_GAS_3 to 44V early and remove some of the ramp down plasma 11 PULSE_GAS_3 to 44V from 0.4 to 0.96sec plasma 12 PULSE_GAS_3 to 48V; ZCUR ramp moved to 0.45-0.55 (was 0.5-0.6) plasma 13 PULSE_GAS_3 to 46V plasma 14 PULSE_GAS_3 to 47V after 0.5sec and lowered between 0.3 & 0.5 plasma 15 enable divertor gas puff system @ 0.35 (from inner wall) plasma 16 drop PULSE_GAS_3 to 44V from 0.6 to 0.9sec plasma 17 no changes plasma 18 IP = -900000 plasma 19 IP=-1000000; enable B_SIDE_UPPER for H2 puff plasma 20 Reload 017; B_SIDE_UPPER puff @ 0.3 (100Vx.01sec) fizzle 21 no changes plasma 22 PULSE_GAS_3 = 40V from 0.5 to .95sec plasma 23 PULSE_GAS_3 raised before 0.3sec plasma 24 IP=-600000; PULSE_GAS_3 to 39V from 0.5 to 0.95sec plasma 25 IP=-400000; IC_EF1's = 2000A plasma 26 Reload 940616023; IP=-1e6; IC_EF1's=4000A plasma 27 Reload 940616025; IP=-250000; IC_EF1's=500A; PULSE_GAS_3 = 41V from 0.5 to 0.95sec plasma

Session Leader Comments
Jun 16 1994 08:53:00:360AM		Steve Golovato	Run 940616 - SL - Golovato PO - Goetz EO - Bertolino ecdc 6-8am starting with shot 940608003, limited plasma like 940603019. fill = 1.2e-5 Goals - 1) finish density scan with limited plasma at 800ka by going to higher densities. will need to tune at these densities. 2) current scan with limited plasmas, 400-1000ka. 3) fast scanning probe profiles with and without rf. 4) icrf into diverted plasmas, get scanning probe data. we won't have scanning probe today so skip goal 3.
Jun 16 1994 08:53:45:780AM	940616001	Steve Golovato	this is fiducial shot. ran well.
Jun 16 1994 09:00:39:520AM	940616002	Steve Golovato	Shot 940616002 - reloaded shot 940608003 with extended flattop to 1 sec and elimination of tom luke's late gas puff. good shot. rf 700-900ms, we want a flat baseline either side of rf to see heating more clearly. tf inverted early, at 800ms instead of 1.1sec
Jun 16 1994 09:03:15:340AM	940616002	Steve Golovato	Shot 940616002 - reloaded shot 940608003 with extended flattop to 1 sec and elimination of tom luke's late gas puff. good shot. rf 700-900ms, we want a flat baseline either side of rf to see heating more clearly. tf inverted early, at 800ms instead of 1.1sec density low.
Jun 16 1994 09:19:55:750AM	940616003	Steve Golovato	Shot 940616003 - even lower density, despite increased puff. pressure in a-side plenum low, accounting for low density so far. raising plenum pressure to 15#.
Jun 16 1994 09:25:58:230AM	940616003	Steve Golovato	Shot 940616003 - even lower density, despite increased puff. pressure in a-side plenum low, accounting for low density so far. raising plenum pressure to 15.5 lbs.
Jun 16 1994 09:28:47:450AM	940616003	Steve Golovato	Shot 940616003 - even lower density, despite increased puff. pressure in a-side plenum low, accounting for low density so far. raising plenum pressure to 15.5 lbs. we've probably been running on what's in the walls.
Jun 16 1994 09:50:05:560AM	940616004	Steve Golovato	Shot 940616004 - outer gap 3 cm, inner gap .5cm, resting on nose. loading too low, raise density, moving plasma out .5cm.
Jun 16 1994 10:02:35:940AM	940616004	Steve Golovato	Shot 940616004 - outer gap 3 cm, inner gap .5cm, resting on nose. loading too low, raise density, moving plasma out .5cm.
Jun 16 1994 10:10:55:480AM	940616005	Steve Golovato	Shot 940616005 - density still low, high power rf interrupted. elongation getting high late in shot. raise gas puff more.
Jun 16 1994 10:34:35:950AM	940616006	Steve Golovato	Shot 940616006 - got the density up, rf mistuned. outer gap 2cm, lower elongation puts plasma on inner wall instead of nose, gas appears to get in better. run with this nl of about 9.e19
Jun 16 1994 10:51:24:430AM	940616007	Steve Golovato	Shot 940616007 - density good , nl=9.5e19, still mistuned.
Jun 16 1994 11:14:55:670AM	940616008	Steve Golovato	Shot 940616008 - walls repleting density risong shot-to-shot. density fluttering at nl+=1.4-1,6e20. looks like elming h-mode. rf still mistuned. lowering gas to get density back down. stored energy increases.
Jun 16 1994 11:25:55:290AM	940616009	Steve Golovato	Shot 940616009 - good shot, rf ran, nl=8.5e19. raise density. del(W_efit)=15kj
Jun 16 1994 11:47:01:020AM	940616010	Steve Golovato	Shot 940616010 - good shot, nl+9.2e19, 1.5MW. raising gas.
Jun 16 1994 11:56:26:160AM	940616010	Steve Golovato	Shot 940616010 - good shot, nl+9.2e19, 1.5MW. raising gas.
Jun 16 1994 12:15:53:960PM	940616011	Steve Golovato	Shot 940616011 - nl=9.5e19, 1.6MW. raise nl more.
Jun 16 1994 12:30:37:650PM	940616012	Steve Golovato	Shot 940616012 - too much density, density fluttering (sawteeth) like shot 8. rf interrupts.
Jun 16 1994 12:51:31:410PM	940616013	Steve Golovato	Shot 940616013 - density ramp has abrupt saturastion at 500ms. try slower rise in gas puff. nl=9.e19, 1.8MW.
Jun 16 1994 01:18:28:440PM	940616014	Steve Golovato	Shot 940616014 - not getting density higher, will try inner wall puffing. dave jablonski is setting it up.
Jun 16 1994 01:39:03:130PM	940616015	Steve Golovato	Shot 940616015 - inner wall puff brought it up to 1.2e20 but rf interrupted. tune rf and try one more shot, then go to current scan.
Jun 16 1994 01:59:19:910PM	940616016	Steve Golovato	Shot 940616016 - got flat nl at 1.2e20, we'll try one more time to tune to this plasma.
Jun 16 1994 02:32:39:700PM	940616017	Steve Golovato	Shot 940616017 - rf ran. 20 ohms loading.
Jun 16 1994 02:41:07:960PM	940616018	Steve Golovato	Shot 940616018- same shot 900 ka. nl=1.2e20.
Jun 16 1994 02:56:01:710PM	940616019	Steve Golovato	Shot 940616019 - disrupted at 650ms, 950ka, 1.5e20.
Jun 16 1994 03:28:55:650PM	940616020	Steve Golovato	Shot 940616020 - back to 800ka (shot 17) and add H puff to see how H concentration affects heating (actually had H puff last shot). FIZZLED!!!!
Jun 16 1994 03:30:36:640PM	940616021	Steve Golovato	Shot 940616021 - retake last shot. 1.e20,1.4MW, 800ka. H puff.
Jun 16 1994 03:53:04:800PM	940616022	Steve Golovato	Shot 940616022 - lower density, keep H puff. turned off inner wall puffing, lowered a-side puff.
Jun 16 1994 04:09:57:860PM	940616023	Steve Golovato	Shot 940616023 - same shot with some tuning, gas tweeking. starting current scan.
Jun 16 1994 04:30:15:220PM	940616024	Steve Golovato	Shot 940616024 - 600ka. good shot, 7.e19, 1.6MW.
Jun 16 1994 04:41:34:540PM	940616025	Steve Golovato	Shot 940616025 - 400ka, tweeked up elongation to keep outer gap from growing.. 5.e19, 1.5MW, 400ka. kappa=1.3, outer gap=3cm.
Jun 16 1994 04:57:44:590PM	940616026	Steve Golovato	Shot 940616026 - 1MA, 1MW, 1.e20, good shot.
Jun 16 1994 05:35:49:020PM	940616026	Steve Golovato	Shot 940616026 - try 250ka, tweek rcur,gas, ef1's. disrupted at 580ms. this was a bad idea.

Physics Operator Comments
Jun 16 1994 08:43:13:560AM		John Goetz	Run 940616 Mini-proposal # 059 - RF Heating at > 1 MW Scan current and density with limited discharges to try and find the best heating scenario. Start from shot 940608003 remove puff from PULSE_GAS_3 and extend gas pulse extend current flattop to 1.0 sec extend IP controller gain switch to 1.0 sec extend RCUR waveform to 1.0 sec ( @0.66 )
Jun 16 1994 08:44:52:150AM	940616001	John Goetz	Shot 940616001: Load 940603015 for fiducial shot For shot 940616002: Load 940608003 and make changes as outlined in NULL shot.
Jun 16 1994 09:15:20:420AM	940616002	John Goetz	Shot 940616002: Plasma - ramp down successful TF inverted at 0.8sec - wrong entry in the engineering logbook chunk taken out of the plasma current at TF inversion For shot 940616003: increase PULSE_GAS_3 to 44V from 0.4 to 0.9sec
Jun 16 1994 09:30:09:000AM	940616003	John Goetz	Shot 940616003: Plasma - ramp down successful very low density - pressure in the A_SIDE plenum has been dropping for the last week because of the longer shots and higher densities. alternator ramped down after a late fault on this shot - cost about 15 minutes of time For shot 940616004: increase pressure in A_SIDE plenum to 15PSIA drop PULSE_GAS_3 to 40V from 0.4 to 0.9 to counter the change in driving pressure
Jun 16 1994 09:52:51:240AM	940616004	John Goetz	Shot 940616004: Plasma - disruption @ 1.125 medium density For shot 940616005: raise PULSE_GAS_3 to 44V from 0.4 to 0.9 RCUR to 0.665 from 0.6 to 1sec to decrease outer gap
Jun 16 1994 10:13:23:020AM	940616005	John Goetz	Shot 940616005: Plasma - almost all the way down density did not respond to increased gas puff - why?? For shot 940616006: IC_EF1's to 3000A from 0.6 to 1.2 to keep elongation down PULSE_GAS_3 to 48V from 0.4 to 0.9 IC_EF4 flattop extended to 0.7sec (was 0.5)
Jun 16 1994 10:34:59:780AM	940616006	John Goetz	Shot 940616006: Plasma - almost all the way down high density - kappa ~ 1.4 - current drooping because of high density For shot 940616007: drop PULSE_GAS_3 by 2V after 0.7sec
Jun 16 1994 10:52:17:490AM	940616007	John Goetz	Shot 940616007: Plasma - almost all the way down high density - kappa ~ 1.4 - current drooping because of high density For shot 940616008: PULSE_GAS_1 second puff 0.65 (90V X .015sec) PULSE_GAS_3 ramp down a little steeper this time to try and hold density constant
Jun 16 1994 11:14:50:090AM	940616008	John Goetz	Shot 940616008: Plasma - disruption @ 1.18 For shot 940616009: PULSE_GAS_3 dropped to 42V @ 0.4 and 32V @ .92
Jun 16 1994 11:34:19:440AM	940616009	John Goetz	Shot 940616009: Plasma - all the way down RF got in - nel ~ 8.5e19 For shot 940616010: PULSE_GAS_3 raised to 44V early - remove some of the ramp down to try and keep density up a little longer
Jun 16 1994 11:48:58:000AM	940616010	John Goetz	Shot 940616010: Plasma - all the way down density 9.2e19 but droops after 0.91sec For shot 940616011: PULSE_GAS_3 raised to 44V from 0.4 to 0.96sec
Jun 16 1994 12:10:24:920PM	940616011	John Goetz	Shot 940616011: Plasma - all the way down density 9.6e19 - drop in density at 0.6sec For shot 940616012: PULSE_GAS_3 raised to 48V from 0.4 to 0.96sec ZCUR ramp moved to 0.45-0.55 (was 0.5-0.6)
Jun 16 1994 12:29:54:200PM	940616012	John Goetz	Shot 940616012: Plasma - disruption @ 1.18 density fluttering around 1.4e20 For shot 940616013: PULSE_GAS_3 to 46V
Jun 16 1994 12:54:14:800PM	940616013	John Goetz	Shot 940616013: Plasma - all the way down nel ~ 8.8e19 For shot 940616014: PULSE_GAS_3 to 47V after 0.5; lowered between 0.3 and 0.5sec it looks like the density is rising too quickly
Jun 16 1994 01:20:27:260PM	940616014	John Goetz	Shot 940616014: Plasma - all the way down nel ~ 8.6e19 before RF For shot 940616015: enable divertor gas puff system @ 0.35sec - from inner wall
Jun 16 1994 01:39:24:200PM	940616015	John Goetz	Shot 940616015: Plasma - all the way down nel ~ 12e19; no RF; not tuned for this density For shot 940616016: drop PULSE_GAS_3 to 44V from 0.6 to 0.9
Jun 16 1994 01:58:58:170PM	940616016	John Goetz	Shot 940616016: Plasma - all the way down nel ~ 11e19; no RF; still not tuned for this density For shot 940616017: one last attempt at these parameters
Jun 16 1994 02:29:56:750PM	940616017	John Goetz	Shot 940616017: Plasma - all the way down nel ~ 11e19; RF ~ 1.5MW For shot 940616018: IP = -900000
Jun 16 1994 02:44:40:000PM	940616018	John Goetz	Shot 940616018: Plasma - all the way down - Ip=.89MA nel ~ 12e19; RF ~ 1.5MW For shot 940616019: IP = -1010000
Jun 16 1994 02:48:46:100PM	940616018	John Goetz	Shot 940616018: Plasma - all the way down - Ip=.89MA nel ~ 12e19; RF ~ 1.5MW For shot 940616019: IP = -1010000 enable B_SIDE_UPPER for H2 puff
Jun 16 1994 03:05:07:570PM	940616019	John Goetz	Shot 940616019: Plasma - disruption @ 0.65sec - Ip = 0.96MA too much density - goes in to flutter mode For shot 940616020: reload shot 940616017 PULSE_GAS_2 puff @ 0.3sec (100V x .01sec)
Jun 16 1994 03:17:31:720PM	940616020	John Goetz	Shot 940616020: fizzle null looks o.k. at the breakdown time For shot 940616021: no changes
Jun 16 1994 03:32:02:630PM	940616021	John Goetz	Shot 940616021: plasma - all the way down nel ~ 11e19 when RF fires For shot 940616022: PULSE_GAS_3=40V from 0.5 to 0.95
Jun 16 1994 03:42:30:840PM	940616022	John Goetz	Shot 940616022: plasma - all the way down nel ~ 7.8e19 when RF fires For shot 940616023: PULSE_GAS_3 raised before 0.3sec
Jun 16 1994 04:01:41:840PM	940616023	John Goetz	Shot 940616023: plasma - all the way down nel ~ 8.0e19 when RF fires For shot 940616024: IP=-600000 PULSE_GAS_3 = 39V from 0.5 to 0.95sec
Jun 16 1994 04:26:02:800PM	940616024	John Goetz	Shot 940616024: plasma - all the way down nel ~ 6.9e19 when RF fires kappa a little low; outer gap ~2.5cm For shot 940616025: IP=-400000 IC_EF1's to 2000A
Jun 16 1994 04:44:48:550PM	940616025	John Goetz	Shot 940616025: plasma - all the way down nel ~ 4.8e19 when RF fires kappa a little low; outer gap ~3.5cm For shot 940616026: Reload 940616023 IP=-1000000 IC_EF1's to 4000A
Jun 16 1994 04:45:42:400PM	940616025	John Goetz	Shot 940616025: plasma - all the way down nel ~ 4.8e19 when RF fires kappa a little low; outer gap ~3.5cm For shot 940616026: Reload 940616023 IP=-1000000 IC_EF1's to 4000A
Jun 16 1994 05:01:32:310PM	940616026	John Goetz	Shot 940616026: plasma - all the way down nel ~ 9.9e19 when RF fires outer gap ~1.5cm For shot 940616027: Reload 940616025 IP=-250000 IC_EF1's to 500A PULSE_GAS_3 = 41V from 0.5 to 0.95sec
Jun 16 1994 05:22:15:830PM	940616027	John Goetz	Shot 940616027: plasma - disruption at .575sec too ambitious a shot

Engineering Operator Comments
Shot	Time	Type	Status	Comment
1	08:33:00:010AM	Plasma	Ok	no faults
2	08:55:29:820AM	Plasma	Ok	no faults
3	09:10:19:260AM	Plasma	Ok	disruption induced comm faults
4	09:37:48:880AM	Plasma	Ok	no faults
5	09:53:26:680AM	Plasma	Ok	disruption induced comm faults
6	10:13:18:560AM	Plasma	Ok	no faults
7	10:32:27:030AM	Plasma	Ok	no faults
8	10:51:04:150AM	Plasma	Ok	disruption induced comm faults
9	11:10:56:300AM	Plasma	Ok
10	11:34:48:120AM	Plasma	Ok	no faults
11	11:55:15:230AM	Plasma	Ok	no faults
12	12:18:40:800PM	Plasma	Ok	disruption induced comm faults
13	12:41:13:510PM	Plasma	Ok	no faults
14	01:01:55:940PM	Plasma	Ok	no faults
15	01:28:21:120PM	Plasma	Ok	nice 800 kA shot; using inner wall gas puffing
16	01:47:04:350PM	Plasma	Ok	another good 800 kA; better density control
17	02:08:35:980PM	Plasma	Ok	good shot
18	02:30:05:510PM	Plasma	Ok	900 kA with no disruptions
19	02:47:30:730PM	Plasma	Ok	950 kA disruption!
20	03:06:24:210PM	Plasma	Ok	Dud after disruption
21	03:19:08:260PM	Plasma	Ok	800 kA no faults
22	03:32:10:590PM	Plasma	Ok	good 800 kA shot; new magnet energy record: 149 MJ delivered
23	03:50:44:720PM	Plasma	Ok	800 ka down to 39 kA by John "no disruptions" Goetz!
24	04:09:22:330PM	Plasma	Ok	Nice 600 kA shot
25	04:28:15:080PM	Plasma	Ok	good 400 kA shot
26	04:47:10:670PM	Plasma	Ok	1 MA, no disruption!
27	05:07:38:340PM	Plasma	Ok	200 kA shot disruted early; no faults