Miniproposals

Miniproposal: 155 Date Filed: 7/15/1996 Title: H-Mode Confinement Scaling MP No. 155 First Author: Martin Greenwald Session Leader: Martin Greenwald (shots 1-33)

Engineering Operator Run Comment

yes

Session Leader Plans

Physics Operators Plans

Session Leader Summaries

Entered: Jul 7 2004 03:49:17:943PM

Author: To Be Determined

Run Summary for 980203 Confinement Scaling MP 155 Session Leader: Greenwald Phys Op: Marmar ============================ Plan: The goal was to extend the parameter range for our h-mode confinement studies. The mp has ambitious goals overall - to scale with Ip, ne, Bt, kappa, and Prf. For this run, we concentrate on Ip. We start with a fiducial shot. then... Bt = 5.6 to avoid ECE cutoff; small ramps will be added to get edge profiles. We will also be getting edge data from the soft xray arrays. The current scan will be much wider Ip = 0.4, 0.6, 0.8, 1.0, 1.2, 1.4 MA Prf ~ 2.5 MW The density scan will be relatively small, we want to work in the vicinity of the ELMfree/EDA boundary; nl04 ~ 1e20. The Ip scan will be repeated for a "high" and "low" density. We want impurity injection (laser blowoff) and impurity confinement times on as many shots as possible. ============================== Results: Mixed, we did run plasmas over the desired current range. Radiation was high, even for EDA plasmas. Stored energy scaled roughly linearly with Ip, though it was about 30% below our best results. Jim got some impurity confinement data - tauI seems to scale with current as well. Bob found scaling of the pedestal width ~ 1/Ip though with some ambiguous shots. We scanned the Bt to allow GPC edge profiles. These didn't show much Ip scaling, suggesting that either the GPC and the edge xray array are looking at quantities with different widths, or that the GPC resolution is to large to see these differences. Fluctuations were seen with Bp probes and on the reflectometer - more analysis needs to be done. Some scanning probe data was obtained at the lower currents. Disruptions limited operation at the highest currents. We got much stronger EDA's at low currents and ELMfree discharges at high currents. This suggests some sort of q dependence on the as yet unknown EDA mechanism. ================================ Shots suitable for further analysis include: 980203006 0.8 MA Fiducial shot 009 0.8 MA 010 0.8 MA 011 0.8 MA 013 0.6 MA 015 0.6 MA 016 0.6 MA 020 0.4 MA 021 0.4 MA 024 1.0 MA 025 1.0 MA 026 1.0 MA 027 1.0 MA 028 1.4 MA 033 1.2 MA

Physics Operator Summaries

Entered: Jul 7 2004 04:36:58:927PM

Author: To Be Determined

physop run summary 980203 SL: Greenwald PO: Marmar EO: Cochrane, Silva, Bertolino MP 155 -- H-mode confinement scaling Discharge clean in deuterium for 2 hours before the run The goal is to extend the parameter range for our h-mode confinement studies. The mp has ambitious goals overall - to scale with Ip, ne, Bt, kappa, and Prf. For this run, we will concentrate on Ip, ne, and Prf. Start with a Tuesday test followed by a fiducial: engineering and gas settings as on 980120025. After a good fiducial: Bt = 5.6 to avoid ECE cutoff; small ramps will be added to get edge profiles. The current scan will be wide Ip = 0.4, 0.6, 0.8, 1.0, 1.2, 1.4 MA Prf ~ 2.5 MW. The density scan will be relatively small, in the vicinity of the ELMfree/EDA boundary: nl04 ~ 1e20. The Ip scan will be repeated for a "high" and "low" density. The power scan will be at 0.8 MA. Prf will be scanned from the minimum for H-mode to the maximum available power, hopefully at least 3 MW. _____________________________________________________________________________ We accomplished a current scan, from .4 MA to 1.4 MA. The H-modes were not great (H typically < 1.5) and there was a lot of radiation on many shots. There were also many shots which disrupted; at least some of the disruptions were caused by large injections. The first attempt at 1.4 MA (shot 28) made it just into rampdown, disrupting at 1.2 MA. 33 data cycles = 28 plasmas + 3 fizzles + 1 test + 1 no power Coldstart hybrid; no problems. load shot from 980120025 load seg 1 from 980123002 1. Tuesday OH test; no fizzle detector; coaxes ok 2. Fiducial attempt; fizzle; B_r too negative 3. B_r offset to .0065 from .0045; plasma; disrupt at .28; many injections 4. PF breaker pulled during init; back to recool; no power shot 5. B_R offset to .006 from .0065; lower seg 4 gas prog volt; plasma; some early hards; disrupt at .54; injections 6. touch the seg 1 gas slightly; plasma; still some hards; H-mode on second RF pulse (1.75 MW) 7. increase pre-puff by 1 msec; plasma; no hards; RF ramping; 8. TF to 5.6 T from 5.3; lower target nl_04 to .83e20 from 1e20; fiddle with late part of ramp-down; magnet resistance fault; dud 9. retry; plasma; target density did not come down much; a few early hards 10. lower puff voltage program; target nl still too high 11. move x-point up 5 mm; lower gas puff voltage; increase nl_04 gain; put twiddle into TF between 1.0 and 1.3 s; add 1 msec to prepuff; plasma 12. 600 kA; nl_04 down to 7.5e19; plasma; injections during RF 13. raise nl_04 prog 10%; add some gas during RF; move RXL up 5 mm; plasma; some RF trips; early hards; 14. EF4 5 amp less -ve at breakdown; fiddle with nl_04 feedback late in RF pulse; fizzle 15. add 1 msec to prepuff; plasma; hards early; 16. EF4 5 more amp less -ve; plasma; no hards 17. 400 kA; fizzle 18. B_r offset to .0065T from .006; plasma; disrupt at .48; vertically unstable 19. reduce clearin by 8 mm; plasma; disrupt at .33; big injection just prior to disrupt. 20. fiddle with I_p time history; plasma; no hards 21. repeat for fast scanning probe; plasma 22. go to 1 MA; load seg 2 from 980123033; lower nl_04 prog & puff volt preprog; plasma; a lot of radiated power during H-mode 23. put TF scan back in; turn gas puff back on during H-mode; plasma; didn't get the puff. 24. modify TF scan; reduce argon; add gas puff after .7 sec; plasma 25. turn off argon; RCUR out by 2 mm; plasma 26. repeat; RF on earlier; plasma 27. ask for higher target density; plasma 28. 1.4 MA; plasma; disrupt on rampdown at 1.2 MA, near q=3; H-modes look ELM-free 29. RCUR in by 3 mm; decrease clearin by 3 mm; plasma; increase nl_04; disrupt on rampup at .53 s; halo waring; EFCU coil stress warning. 30. slow current ramp slightly; increase clearin 3 mm; decrease RCUR 1 mm; delay RF; plasma; disrupt at .9 s; halo warning 31. reload seg 2 from shot 28; increase nl_04; slow I_p ramp slightly; decrease RCUR 2 mm; decrease clearin 2 mm; increase EF4 PLC limit to -10kA; plasma; disrupt at .7 s 32. 1.2 MA; plasma; disrupt at .34s; brick 33. retry; plasma; multiple H-modes.

Session Leader Comments
Feb 3 1998 09:03:44:280AM		Martin Greenwald	Run plan for mp 155 H-mode confinement scaling The goal here is to extend the parameter range for our h-mode confinement studies. The mp has ambitious goals overall - to scale with Ip, ne, Bt, kappa, and Prf. For this run, we will concentrate on Ip, ne, and Prf. We should start with a fiducial shot. then... Bt = 5.6 to avoid ECE cutoff; small ramps will be added to get edge profiles. We will also be getting edge data from the soft xray arrays. The current scan will be much wider Ip = 0.4, 0.6, 0.8, 1.0, 1.2, 1.4 MA Prf ~ 2.5 MW The density scan will be relatively small, we want to work in the vicinity of the ELMfree/EDA boundary; nl04 ~ 1e20. The Ip scan will be repeated for a "high" and "low" density. The power scan will be at 0.8 MA, this widens the scrapeoff and makes RF coupling easier. Prf will be scanned from the minimum for H-mode to the maximum available power, hopefully at least 3 MW. We want impurity injection (laser blowoff) and impurity confinement times on as many shots as possible.
Feb 3 1998 09:46:53:990AM	980203002	Martin Greenwald	fizzle
Feb 3 1998 10:04:23:600AM	980203003	Martin Greenwald	short plasma, disrupts at 0.3 sec
Feb 3 1998 10:14:40:680AM	980203005	Martin Greenwald	Got a bit farther, reach 0.8 MA at .55 seconds, then disrupted
Feb 3 1998 10:28:14:750AM	980203006	Martin Greenwald	Good fiducial
Feb 3 1998 10:54:30:130AM	980203007	Martin Greenwald	Similar shot, but with RF ramp to calibrate power programming
Feb 3 1998 10:55:10:050AM	980203008	Martin Greenwald	PS fault
Feb 3 1998 11:05:52:790AM	980203009	Martin Greenwald	Good Shot, density still a bit high Bt = 5.6 Ip = 0.8 Prf = 2.65 ne target = 1.6 div n0 targe = 15 Wmhd = 0.124
Feb 3 1998 11:23:00:130AM	980203010	Martin Greenwald	Good Shot Bt = 5.6 Ip = 0.8 Prf = 2.5 ne target = 1.5 div n0 = 10 Wmhd = 0.12
Feb 3 1998 11:44:23:750AM	980203011	Martin Greenwald	Good Shot Bt = 5.6 Ip = 0.8 Prf = 2.5 ne target = 1.4 div n0 = 12 Wmhd = 0.13
Feb 3 1998 12:01:38:890PM	980203012	Martin Greenwald	Ip lowered to 0.6 MA several large injections, interupt H-modes
Feb 3 1998 12:12:29:870PM	980203013	Martin Greenwald	OK Shot, multiple RF trips Bt = 5.6 Ip = 0.6 Prf = 2.5 (tripping to 1.2) ne target = 1.3 div n0 = 15 Wmhd = 0.8
Feb 3 1998 12:29:55:790PM	980203014	Martin Greenwald	Fizzle
Feb 3 1998 12:37:51:380PM	980203015	Martin Greenwald	Good Shot Bt = 5.6 Ip = 0.6 Prf = 2.4 ne target = 1.3 div n0 = 17 Wmhd = .08
Feb 3 1998 01:01:12:360PM	980203016	Martin Greenwald	Repeat of 15
Feb 3 1998 01:01:47:750PM	980203017	Martin Greenwald	fizzle
Feb 3 1998 01:26:28:180PM	980203019	Martin Greenwald	early disruption
Feb 3 1998 01:38:45:260PM	980203020	Martin Greenwald	Good Shot Bt = 5.6 Ip = 0.4 Prf = 2.5 ne target = 1.3 div n0 = 15 Wmhd = .05
Feb 3 1998 01:59:00:790PM	980203021	Martin Greenwald	Good Shot Bt = 5.6 Ip = 0.4 Prf = 2.4 ne target = 1.2 div n0 = 15 Wmhd = .052
Feb 3 1998 02:12:38:050PM	980203022	Martin Greenwald	First try at 1 MA H-mode only lasts .22 sec Prad comes up to 2.5 MW Wmhd reaches .144
Feb 3 1998 02:28:26:030PM	980203023	Martin Greenwald	very similar to shot 22
Feb 3 1998 02:41:00:040PM	980203024	Martin Greenwald	Similar to 22, three separate h-mode phases
Feb 3 1998 03:00:08:540PM	980203025	Martin Greenwald	same as 24
Feb 3 1998 03:09:39:310PM	980203026	Martin Greenwald	longer RF pulse 4 distinct h-modes
Feb 3 1998 03:20:34:350PM	980203027	Martin Greenwald	ditto
Feb 3 1998 03:41:56:590PM	980203028	Martin Greenwald	multiple elmfree h-modes ip = 1.4 MA
Feb 3 1998 03:56:49:530PM	980203029	Martin Greenwald	Early disruption
Feb 3 1998 04:16:31:380PM	980203030	Martin Greenwald	1.4 MA early disruption 1 elm-free h-mode period multiple rf trips
Feb 3 1998 04:31:54:810PM	980203031	Martin Greenwald	early disruption
Feb 3 1998 04:44:57:500PM	980203032	Martin Greenwald	attempt at 1.2 MA early disruption
Feb 3 1998 04:58:28:520PM	980203033	Martin Greenwald	1.2 MA multiple elm-free h-modes

Physics Operator Comments
Feb 3 1998 08:56:08:860AM		Earl Marmar	Run plan for 980203 MP 155 -- H-mode confinement scaling Discharge clean in deuterium for 2 hours before the run The goal is to extend the parameter range for our h-mode confinement studies. The mp has ambitious goals overall - to scale with Ip, ne, Bt, kappa, and Prf. For this run, we will concentrate on Ip, ne, and Prf. Start with a Tuesday test followed by a fiducial: engineering and gas settings as on 980120025. After a good fiducial: Bt = 5.6 to avoid ECE cutoff; small ramps will be added to get edge profiles. The current scan will be wide Ip = 0.4, 0.6, 0.8, 1.0, 1.2, 1.4 MA Prf ~ 2.5 MW. The density scan will be relatively small, in the vicinity of the ELMfree/EDA boundary: nl04 ~ 1e20. The Ip scan will be repeated for a "high" and "low" density. The power scan will be at 0.8 MA. Prf will be scanned from the minimum for H-mode to the maximum available power, hopefully at least 3 MW.
Feb 3 1998 08:58:20:230AM		Earl Marmar	Coldstart hybrid; no problems. load shot from 980120025 load seg 1 from 980123002
Feb 3 1998 09:44:32:380AM	980203002	Earl Marmar	Fiducial attempt; fizzle; B_r too negative
Feb 3 1998 10:06:55:510AM	980203003	Earl Marmar	B_r offset to .0065 from .0045; plasma; disrupt at .28; many injections
Feb 3 1998 10:07:08:040AM	980203004	Earl Marmar	PF breaker pulled during init; back to recool; no power shot
Feb 3 1998 10:56:12:830AM	980203005	Earl Marmar	B_R offset to .006 from .0065; lower seg 4 gas prog volt; plasma; some early hards; disrupt at .54; injections
Feb 3 1998 10:56:24:760AM	980203006	Earl Marmar	touch the seg 1 gas slightly; plasma; still some hards; H-mode on second RF pulse (1.75 MW)
Feb 3 1998 10:56:37:630AM	980203007	Earl Marmar	increase pre-puff by 1 msec; plasma; no hards; RF ramping
Feb 3 1998 10:56:50:310AM	980203008	Earl Marmar	TF to 5.6 T from 5.3; lower target nl_04 to .83e20 from 1e20; fiddle with late part of ramp-down; magnet resistance fault; dud

Engineering Operator Comments
Shot	Time	Type	Status	Comment
1	09:08:58:330AM	Test	Bad	no fizzle detector
2	09:38:39:830AM	Plasma	Ok
3	09:47:17:610AM	Plasma	Ok
4	09:56:40:410AM	Test	Ok	OH1 sel power ckt fired in A&B, PLC sync shot no power. fault occured wh
5	10:12:22:150AM	Plasma	Ok	no faults/plasma
6	10:22:12:540AM	Plasma	Ok	no faults/plasma
7	10:34:47:450AM	Plasma	Ok	no faults/plasma
8	10:52:57:550AM	Plasma	Bad	mag. res. flt
9	10:59:36:000AM	Plasma	Ok
10	11:14:54:200AM	Plasma	Ok
11	11:36:09:580AM	Plasma	Ok
12	11:48:48:370AM	Plasma	Ok
13	12:05:22:060PM	Plasma	Ok
14	12:21:40:560PM	Plasma	Ok
15	12:31:29:530PM	Plasma	Ok
16	12:46:50:510PM	Plasma	Ok
17	12:59:51:280PM	Plasma	Ok	fizzle
18	01:10:03:880PM	Plasma	Ok
19	01:22:45:290PM	Plasma	Ok
20	01:33:04:480PM	Plasma	Ok
21	01:49:58:880PM	Plasma	Ok
22	02:05:02:860PM	Plasma	Ok
23	02:19:27:370PM	Plasma	Ok
24	02:36:17:670PM	Plasma	Ok
25	02:47:12:550PM	Plasma	Ok
26	03:04:57:230PM	Plasma	Ok
27	03:16:57:420PM	Plasma	Ok
28	03:32:48:740PM	Plasma	Ok
29	03:50:53:280PM	Plasma	Ok
30	04:11:23:930PM	Plasma	Ok
31	04:29:33:390PM	Plasma	Ok
32	04:41:41:730PM	Plasma	Ok
33	04:54:46:160PM	Plasma	Ok