Miniproposals

Miniproposal: 132 Date Filed: 12/20/1995 Title: ICRF H Mode Confinement With Boronized Walls First Author: Steve Golovato Session Leader: Steve Golovato (shots 1-39)

Miniproposal: 143a Date Filed: 12/12/1997 Title: Triangularity Scan in H-Mode (143 revised) First Author: Martin Greenwald Session Leader: Steve Golovato (shots 1-39)

Engineering Operator Run Comment

Hutch

Session Leader Plans

Physics Operators Plans

Session Leader Summaries

Entered: Jul 7 2004 03:49:15:180PM

Author: To Be Determined

Run summary - 960214 SL: Golovato PO: Hutchinson EO: Silva/Bertolino Run 960214 - Continuation of H-mode studies at 5.3T with bori=onized walls. Today's Goals: (1) establish good H-modes. (2) impurity injection to measure particle confinement in H-mode. (3) increase triangularity to improve H-modes, try to access VH-mode. ECDC in He all night prior to run. This run was very successful with numerous high quality H-mode shots. It took a few shots to get going, with disruption problems trying to run above 1 MA and some rf voltage trips until we got the outer gap and position feedback working correctly. We also had moly bricks occasionally. From shot 14, things ran well. Shot 18 was the best shot before we started increasing triangularity, with 200 kJ of stored energy and a neutron rate of 1.e14. We then tried a little lower density, lowering the programmed nl04 from 0.8e20 to 0.7e20 and had trouble getting H-modes. We went back up in density getting good shots again for shot 25. Shots 27,30, and 35 had stored energy near 200kJ and high neutron rates, with shot 35 a record 1.28e14. These shots also had central Te of 4.5-5 keV. We then did unscheduled Btor and nl04 scans for shots 34-39. Stored energy degrades only weakly for off-axis heating, still 165 kJ for 6.2T (shot 37), heating outside q=1. We also continued to get good H-modes with higher initial densities, up to nl04=1.3e20 on shot 39. The good H-modes for this run were characterized by a fast initial rises in density, stored energy, and radiated power. At some point the radiated power is too high (more than input power) and things degrade, either remaining in a poorer H-mode as on shots 18, 27, and 30 or by falling out of H-mode as on shot 35. The good H-modes were elm-free, with the rollover in density rise coinciding with the development of an H-alpha blob if it doesn't fall out of H-mode. Even the higher initial density shot 39 was elm-free, with only a weak blob as the density stopped rising. The peak radiated power increased as the triangularity increased. This may have been related to the decreased inner and outer gaps of these plasmas. The outer gap went from 6mm on shot 18 to only 4mm on shot 35. It was even smaller on shots 36-39, being as low as 2mm at times. The good phases of the H-modes had H-factors of above 2, Tau_E_global of 70-80ms, and 1.4 times ITER elm-free H-mode. Throughout the run laser blowoff experiments were being done. The following is Jim Terry's summary of these experiments. Using the laser blow-off system, Sc was injected into the H-mode discharges, and its transport was tracked by observing lines from both Li-like and He-like Sc. Two regimes of H-mode impurity particle confinement were observed, one with essentially infinite confinment time (during the phase with good H factors) which degraded (typically at the same time that the stored energy stopped rising) to a regime with tau_imp approximately equal to 100 ms. This is still significantly larger than the L-mode tau_imp, which is typically 20 ms! Both regimes of H-mode impurity confinement with boronized walls have longer confinement times than the H-mode confinement measured with unboronized walls. For the set of constant shots 16-20, spatial scans of the Li- and He-like charge states were done in hopes of measuring the local impurity transport coeffients. Profile peaking was observed. During the spatial scan HIREX observed strong poloidal rotation in He-like Sc. For information on engineering problems and shot statistics, see the physics operator summary. For shot-to-shot comments, see the logbook under the session_leader topic.

Physics Operator Summaries

Entered: Jul 7 2004 04:36:56:113PM

Author: To Be Determined

Physop Summary 960214 MP 132 Boronized H-mode, MP143 High triangularity. _________________________________________________________________________ PO Hutch SL Golovato Engineering setup: ------------------ Overnight ECDC in He. Fill A-side (really K-side) to 20psi D2 Fill B-top with 5psi D2 Fill B-side lower with 4psi Argon Plan ____ Fiducial as per 960130002 Then 1.1 MA as per 960130040. Obtain good ICRF-heated plasmas, preferably ELM-free. Apply Scandium injection for impurity confinement measurements. Increase upper triangularity to see if we can see signs of VH mode. (Investigate impurity screening? Who is supposed to be doing this?) Summary _______ Basically achieved the whole plan but at 1MA because 1.1 proved unpleasantly disruptive. Higher triangularity was obtained by (1) Lowering RXU to -.04m. (2) Raising ZCUR to 0. (3) Lowering ZXU a bit to +.035. The last few shots are reasonable examples. Even more gas was required in the current ramp to prevent excessive Ip ramp rates. The B-side (feedback) valve was the most useful for this using V in segment 1. This might be a function of the overnight He ECDC. Much impurity blowoff data was obtained. Impurity confinement time was found to be essentially infinite during ELM-free H-modes. This is consistent with the observation made previously that the Mo and radiatioin just "integrates up" during this phase. Typically with the normal upper triangularity the H-alpha blob helps to overcome this. The higher triangularity shots seemed to obtain truly ELM-free H-modes more easily and so impurity integration happens. They typically seemed to revert to L-mode rather than developing a blob. The highest density, nl04 1.2e20(shot39), had small ELMs develop instead. Also, the higher triangularity allowed a higher range of initial density with blob-free operation. Only shots 32 and 33 had a fully double null, during a vertical instability that occurred when ZXU was lowered and clearin increased. We did not have time to fix that so we shied away. Most the the high upper triangularity shots are close to double null and have even less flux that makes it all the way round to the inner divertor. (Thus blowing away the theory that it is important to have the recycling at the inner divertor for good H-modes.) No obvious signs of "VH-mode" were observed, although what that would consist of is not so obvious. Most plasmas had good H-factors spoiled eventually by radiation. Scorecard _________ Shot,Duration(s),Ipmax(MA) Shot,Duration(s),Ipmax 1 0.000 0.008 2 0.000 0.005 3 1.538 0.830 4 0.236 0.789 5 1.259 1.122 6 0.000 0.026 7 0.805 1.233 8 1.709 0.941 9 1.710 0.939 10 1.708 1.037 11 1.706 1.034 12 1.708 1.039 13 0.842 1.207 14 1.709 1.039 15 0.280 0.781 16 1.709 1.042 17 1.127 1.042 18 1.708 1.042 19 1.709 1.042 20 1.709 1.039 21 0.000 0.011 22 1.005 1.091 23 0.000 0.031 24 1.359 1.021 25 1.709 1.039 26 1.709 1.039 27 1.710 1.042 28 1.710 1.045 29 0.028 0.112 30 1.712 1.045 31 1.111 1.039 32 0.555 1.032 33 0.544 1.021 34 1.711 1.039 35 1.710 1.047 36 1.710 1.044 37 1.711 1.042 38 1.710 1.040 39 1.710 1.035 Finished summary for 960214 Total of 39 shots. 39 shots. 34 plasmas. 2 fizzles. 3 duds. Fizzle = gt 17 lt 50kA. Details _______ Load 960130002 Fill puff is -515 to -504 1 PStest New TF filter causes crowbar. Remove. New ratiomatic gives 3.2e-7 versus the big-board gauge value 2.8e-7. Calibrated F-side p_o gives .00115 mtorr. 2 Engineering screw up. TF only. Reasonable agreement between the B-bot MKS and f-side ratiomatic gauges at approx 1 mtorr. 3 Fid Hard xray warning. Big Mo injection. Initial p_o 2.6e-2 mtorr. Load 960130040. nl04 to .8 (was .7). Add a second fill puff at -50 to -20ms: idea to get some gas coming in during rise. Argon enabled. 4 Dis Early disruption at .2s, incredibly fast current rise. A brick at .2s. kills it. Second fill-puff to -60 to -20ms. Otherwise a repeat. 5 Dis Disrupts at 1.25s. No H-mode, strange! Halo warning. Repeat. No argon. 6 Fiz No obvious reason, although the fill has drifted up to 0.04mtorr. Reduce 1st fill to 11ms. 7 Dis At .8s. VDE for no obvious reason. Reduce Ip to .9MA, reduce RXL scan maximum to .002, from .008. 8 OK p_o 3.4e-5 RF modulated. good H-modes. RF RCUR feedback to -2000, was off. 9 OK Radiative event at .76 is claimed by JT not to be their injection at .75s. Looks like a Mo injection. RF pulls the plasma out at 1s when the E-port trips by nearly 1cm. RCUR to .679, right gap goes to zero. RF RCUR feedback to -1200. Ip to 1.0MA. Enable Argon. 10 OK RF drops out a couple of times. Still a Mo injection at .79s. Repeat with earlier RF. 11 OK Forgot to load PCS changes. Argon to 13ms. from 20ms. RF feedback to -1800. 2nd fill extended to -11ms. 12 OK One RF trip. Still MO injections at .7s. RCUR drawn to .662 (was .66) to help RF coupling. IP to 1.1MA RXL sweep minimum to -.004 from -.007. 13 Dis At .8s due to radiation death.Relatively slow Mo accumulation but to a high level. Ip to 1.MA, RXL to 0.00 at .6s. 14 OK Good steady H-mode. but with lots of steady radiation accumulation. Seems ELM-free. 180kJ. Slower current rise. RXL to +.002 at .6s. 15 Dis At .27 s. Mo Brick. The current rise on this shot is 20% faster than on 14. perhaps this is a cause of the problems. Repeat 16 OK Nice continuous H-mode. Injection at .9s. 183 kJ Reduced current rise rate. 460kA at .1s. Interferometer problem at end of shot may be an object. 2nd fill to 0s. Puff to 90V at .03s. 17 Dis At 1.1s: a beautiful TV view of teh brick enterung at A-port from low and outside. H-mode ELM free till abou t.85 when the lump starts up. Fast rise. 534kA at .1s. 188kJ. Puff to 90V at .05s (as well as at .03s). 18 OK Intermediate IP-rise 470kA at .1s. Mo accumulation. 199kJ. RXL to .004 at .85s (was .002) 19 OK Ip 530kA at .1s. 188kJ radiation a bit worse. Puff to 70V at .01s (was 50V). Ramp RXU to -.02 at 1s (.015 as before, at .8s). 20 OK Ip=500kA at .1s. 182kJ. Halpha blob is beginning to show. nl04 to .7, RXU to -.004 at 1s. (ramp still). 21 PSdud. 22 Dis at 1.s. Less than 1MW RF. No H-mode. Threshold point for Amanda? Hit by a brick. Triangularity clearly increased at the ramp end. Ramp zcur -.02 at .5s, -.015 at 1.s (was -.02 throughout) 23 Fiz p_o =3.3e-2 mtorr 1st fill to 10ms, 2nd fill to -50 to 0ms. 24 OK Disrupts at 1.34. 472kA at .1s. No H-mode. 1.2MW RF. Big Mo injection at .26s. p_o=.28mtorr. Raise nl04 to .8 in case that is the RF's problem. RCUR to -.01 at 1.s 25 OK Good shot despite Mo injection at .4s. Make the RXU ramp earlier. Lower RXL earlier. ZXL to -.01 thoughout flat-top. 183KJ. 26 OK Mo injections around .7s. Recovers only to 160kJ. Ip=487 at .1s. zcur to -0.005, RXU kept at -.04 from .5s onward. RXL not swept lower than -.004 (removed the end sweep) 27 OK 511kA at .1s. Record neutron rate 1.2e14. ELM-free till .8s when radiation accumulation gets too much. 204kJ in ELM-free, 150kJ later. zcur to 0 at .55s. 28 OK Mo injection at 0.28s. Quite close to double null. 184kJ. 503 kA at .1s. Tweak zcur and rxu to values a bit earlier. Otherwise repeat. 29 Dis Strange termination at 25ms 11okA with high density. Fill has risen to 3.1e-2 mtorr. 2nd fill puff to -40 to 0ms. 30 OK 203kJ, done in by radiation accumulation. Ip=443kA at .1s Slight current hesitation p_o=2.8e-2 mtorr. RXU to -.05. 2nd fill to -30 to 0ms. 1st point on gas puff to 80V from 100V. RXL moved out about 1mm at .7s in case this is a partial cause of the Mo. 31 Dis At 1.08s. 197kJ. 498kA at .1s. SOL power ramps down to zero and we lose H-mode. Then a second H-mode starts up and the drop out of that seems to trigger the disruption. This is a very low H-alpha shot. Disable Argon. ZXU to +.025 from +.04. Increase clearin a tad to 0. 32 Dis Vertical instability at .5s. OH1 seems to have an oscillation before that. ZXU to .035 from .025 33 Dis Similar problem. Load 31. 34 OK Three ELM-free periods. Mo injection at .7s. 170 kJ. Gentle zxu ramp to .4 at .7s. 35 OK 2 ELM-free periods. Mo injection at .76s. 544kA at .1s, signs of disruptions. 196kJ. Bt to 5.8T. Raise puff at .075s to 65V. 36 OK 3 ELM-free. ZXU to .35 at .7s. Bt= 6.2T, Small inward tweak on RXL. 37 OK 2 ELM-frees. Extra radiation rise at .82s is due to laser blow off. nl04 to 1.e20, Bt=5.5T 38 OK Good but RF trips out. 203kJ. nl04 to 1.2e20. 39 OK Stays in H-mode. Radiated power controlled by small ELMS starting .88s.

Session Leader Comments
Feb 14 1996 09:03:11:880AM		Steve Golovato	run 960214 - Continuation of H-mode studies with boronization. Today's Goals: (1) establish good H-modes. (2) impurity injection to measure particle confinement in H-mode. (3) increase triangularity to try to access VH-mode. ECDC in He all night prior to run.
Feb 14 1996 09:03:44:700AM	960214001	Steve Golovato	shot 960214001 - tf test.
Feb 14 1996 09:04:29:110AM	960214002	Steve Golovato	shot 960214002 - fiducial. only tf ran, another tf test.
Feb 14 1996 09:22:34:350AM	960214003	Steve Golovato	shot 960214003 - fiducial. plasma.
Feb 14 1996 09:24:25:710AM	960214004	Steve Golovato	shot 960214004 - load shot 960130040. 1.1MA, nl04(prog)=1.e20 dsirupted at 230ms.
Feb 14 1996 09:42:42:170AM	960214005	Steve Golovato	shot 960214005 - repeat. plasma, no h-mode, d-port tripping, e-port ended early. had 2.5MW for some time, still no h-mode.
Feb 14 1996 09:45:20:670AM	960214006	Steve Golovato	shot 960214006 - repeat. fizzle.
Feb 14 1996 09:56:35:730AM	960214007	Steve Golovato	shot 960214007 - repeat. plasma. disrupted at 800ms.
Feb 14 1996 10:16:15:860AM	960214008	Steve Golovato	shot 960214008 - repeat, lower Ip to 1MA.. plasma., good h-mode, e-port hit voltage limit. lower power a little and turn on position feedback in pcs (it was off for some reason).
Feb 14 1996 10:40:46:100AM	960214009	Steve Golovato	shot 960214009 - repeat with position feedback on. Ip about 900ka, plasma. spontaneous injection at 770ms. scandium injection at 750ms. lose h-mode temporarily at 770ms. plasma pulled into antenna at 1s. error in feedback settings caused this. offset was set 20ms early instead of 20ms later than rf turnoff. when it went off, error signal went to positive rail, pulling plasma hard into antenna. this caused rf trip and sample and hold to keep feedback on rail unitl gate turned off at 1.05s. we should reduce the positive rail to about .3v from .5 v. .
Feb 14 1996 10:50:29:270AM	960214010	Steve Golovato	shot 960214010 - repeat with position feedback gain reducec to -1200v. Ip to 1MA. plasma, multiple h-modes, can't seem to get a steady h-mode. voltage limit trips on d and e.
Feb 14 1996 10:57:13:150AM	960214011	Steve Golovato	shot 960214011 - increase feedback gain to -1800 to raise loading, avoid voltage limit trips. start rf earlier, at .6s from .7s. plasma. still voltage trips, higher fb gain not loaded.
Feb 14 1996 11:12:39:020AM	960214012	Steve Golovato	shot 960214012 - lowered power a little on both antennas. plasma, still hit voltage limit at e-port.
Feb 14 1996 11:21:47:280AM	960214013	Steve Golovato	shot 960214013 - moved plasma out to increase loading, this was not done previously. also raised current to 1.1MA. plasma. disrupted at 840ms. e-port still hit voltage limit.
Feb 14 1996 11:35:03:660AM	960214014	Steve Golovato	shot 960214014 - back to 1MA, lowered e-port power a little. plasma. steady h-mode at 2.2MW. stored energy turns over at 810ms when radiated power peaks.
Feb 14 1996 11:36:48:680AM	960214015	Steve Golovato	shot 960214015 - repeat, playing with strike point. plasma, disrupted at 270ms, hit by brick.
Feb 14 1996 11:57:10:130AM	960214016	Steve Golovato	shot 960214016 - repeat. plasma. good steady h-mode, 184kj, 2.5MW. best shot yet today.
Feb 14 1996 12:11:51:840PM	960214017	Steve Golovato	shot 960214017 - repeat. plasma. good steady h-mode, 184kj, 2.5MW. best shot yet today.
Feb 14 1996 12:18:00:130PM	960214018	Steve Golovato	shot 960214018 - repeat. plasma. good steady h-mode, 200kj, 2.5MW. neutron rate 1.e14. prad takes off, stored energy turns over. quite a good shot. Te0=4.5kev
Feb 14 1996 12:27:13:990PM	960214019	Steve Golovato	shot 960214019 - repeat. plasma. not quite as good as last shot.
Feb 14 1996 12:47:43:400PM	960214020	Steve Golovato	shot 960214020 - repeat. plasma. about the smae as previous shor.
Feb 14 1996 12:48:20:360PM	960214021	Steve Golovato	shot 960214021 - start increasing upper triangularity late in shot. dud.
Feb 14 1996 01:07:41:220PM	960214022	Steve Golovato	shot 960214022 - nl04(prog)=.7e20 from .8e20. plasma. no h-mode. disrupted at 1s. rf mistuned for this density.
Feb 14 1996 01:08:08:710PM	960214023	Steve Golovato	shot 960214023 - repeat. fizzle.
Feb 14 1996 01:27:26:150PM	960214024	Steve Golovato	shot 960214024 - repeat, tuned e-port. plasma. d-port didn't run, no h-mode. go back to higher nl prog.
Feb 14 1996 01:44:39:680PM	960214025	Steve Golovato	shot 960214025 - go back to nl prog.= .8e20. plasma. h-mode, 2.5MW, 183kj. neutron rate=9.e13.
Feb 14 1996 01:53:02:440PM	960214026	Steve Golovato	shot 960214026 - more triangularity. plasma, brick at 780ms kills h-mode temporarily. h-mode persists well into rampdown, to 1.35s.
Feb 14 1996 02:06:30:310PM	960214027	Steve Golovato	shot 960214027 - more triangularity. plasma. h-mode degrades at 850ms when h-alpha blob forms. new record neutron rate, 1.2e14. te0=4.9keV. Wp=204kj. h-factor over 2, 70-80ms tau_E.
Feb 14 1996 02:21:00:250PM	960214028	Steve Golovato	shot 960214028 - more triangularity. plasma. looks much like last shot, slightly lower parameters.
Feb 14 1996 02:21:13:080PM	960214029	Steve Golovato	shot 960214029 - more triangularity. fizzle.
Feb 14 1996 02:24:08:700PM	960214029	Steve Golovato	shot 960214029 - more triangularity. fizzle.
Feb 14 1996 03:13:16:080PM	960214030	Steve Golovato	shot 960214030 - repeat. plasma. h-alpha blob starts at 890ms. 203kj. about the same as shot 27.
Feb 14 1996 03:25:34:850PM	960214031	Steve Golovato	shot 960214031 - much like 27 and 30. Te0=5kev. lose h-mode temporarily at 890ms.
Feb 14 1996 04:00:52:210PM	960214033	Steve Golovato	shot 960214033 - another early disruption, at 540ms.
Feb 14 1996 04:13:06:250PM	960214034	Steve Golovato	shot 960214034 - plasma finally. stored energy and radiated power scream up, then lose h-mode. happens three times.
Feb 14 1996 04:23:31:700PM	960214035	Steve Golovato	shot 960214035 - small tweak in triangularity. plasma. first h-mode lasts to 860ms. Te0>5kev, record neutrin rate = 1.28e14.
Feb 14 1996 04:30:49:650PM	960214036	Steve Golovato	shot 960214036 - raise Bt to 5.8T, to heat off-axis, maybe suppress sawteeth. plasma. three h-modes, reduced sawteeth, heating still pretty good. 173kj.
Feb 14 1996 04:45:09:170PM	960214037	Steve Golovato	shot 960214037 - raise Bt to 6.2T, to heat outside q=1. plasma, heating still pretty good, 165kj. still have small sawteeth.
Feb 14 1996 04:58:48:580PM	960214038	Steve Golovato	shot 960214038 - Bt to 5.5T, doing a scan. plasma.,,good h-mode,203kj. nl04 prog raised to 1.e20 for this shot.
Feb 14 1996 05:08:09:460PM	960214039	Steve Golovato	shot 960214039 - Bt still 5.5T, nl04 prog raised to 1.2e20. plasma. good shot, very elm-free like previous shots.

Physics Operator Comments

Engineering Operator Comments
Shot	Time	Type	Status	Comment
1	08:17:54:190AM	Test	Bad	tf filter test-blown fuse
2	08:59:00:360AM	Test	Ok	tf
3	09:05:54:750AM	Plasma	Ok	fiducial ok
4	09:20:20:170AM	Plasma	Ok	comm fault oh1
5	09:30:50:510AM	Plasma	Ok
6	09:41:52:060AM	Plasma	Ok
7	09:52:11:570AM	Plasma	Ok
8	10:04:18:350AM	Plasma	Ok
9	10:18:43:840AM	Plasma	Ok
10	10:37:44:720AM	Plasma	Ok
11	10:50:18:460AM	Plasma	Ok
12	10:59:06:570AM	Plasma	Ok
13	11:10:54:150AM	Plasma	Ok
14	11:21:48:630AM	Plasma	Ok
15	11:33:22:380AM	Plasma	Ok
16	11:42:05:260AM	Plasma	Ok
17	11:55:12:890AM	Plasma	Ok
18	12:05:49:980PM	Plasma	Ok
19	12:16:46:570PM	Plasma	Ok
20	12:27:27:490PM	Plasma	Ok
21	12:40:51:510PM	Plasma	Ok	oh2l comm fault
22	12:54:36:250PM	Plasma	Ok
23	01:06:38:570PM	Plasma	Ok
24	01:15:39:130PM	Plasma	Ok
25	01:29:27:410PM	Plasma	Ok
26	01:41:38:600PM	Plasma	Ok
27	01:53:46:490PM	Plasma	Ok
28	02:06:23:720PM	Plasma	Ok
29	02:19:33:920PM	Plasma	Ok
30	02:28:37:130PM	Plasma	Ok
31	03:13:36:540PM	Plasma	Ok
32	03:41:47:460PM	Plasma	Ok
33	03:53:09:580PM	Plasma	Ok
34	04:02:23:000PM	Plasma	Ok
35	04:12:42:510PM	Plasma	Ok
36	04:22:29:890PM	Plasma	Ok
37	04:33:59:450PM	Plasma	Ok
38	04:47:32:650PM	Plasma	Ok
39	04:59:12:310PM	Plasma	Ok