Miniproposals

Miniproposal: 046 Date Filed: 4/7/1994 Title: Ohmic Confinement First Author: Martin Greenwald Session Leader: Martin Greenwald (shots 1-7)

Engineering Operator Run Comment

horne

Session Leader Plans

Physics Operators Plans

Session Leader Summaries

Physics Operator Summaries

Entered: Jul 7 2004 04:36:54:410PM

Author: To Be Determined

Run Report -- 950616 -- Ohmic confinement studies. (Greenwald, Horne, Bertolino). Aborted after 2 plasma shots due to blocked TCI port. Kappa predictor/controller seem to work. Shot 6 may be useful to load if anybody needs a kappa=1.1 shot. Otherwise the run is a bust. ======== Turn off integrator C -- everything it's hooked to is off. Note that integrator A controls slow ZCUR and KAPPA. Coldstart at 8:05 shot 1,2 no power test 3 test oh2 & tf; also Irby to cell to massage TCI. 4 Another OH2 test. Hope it's the last one. 5 First plasma attempt, init at 9:30. Plasma, ramped down nicely. By 700 ms kappa looks nice. Reduce ic_ef4 gain crowbars to 90 msec Draw kapp=0 for full shot 6 Plasma. Remains limited for whole shot, nice rampdown. ef2xef4 is doing something very wierd. set ef2xef4 gain at 1.5 at .1 sec. Increase kappa gain to 8 Reduce drawn nl to 2.e19 (gulp!) Reduce pulse_gas3 V to 20 V 7 type 3 faults during check. "All sorts of bad things happened" Set TF invert to 1 sec set ZXL down 3 cm, zxu u 3 cm. Adjust rcur ptogramming to be flat at .665. ====== There is an object blocking part of the TCI vertical port. ============ Preponderance of opinion is that it's a tile. 7 Reduce rcur after next shot

Session Leader Comments
May 16 1995 08:41:06:520AM		Martin Greenwald	Run Plan for Ohmic Confinement Studies - 950516 ----------------------------------------------- Test possible explanations for the observed difference in confinement scaling between C-Mod and Alcator C. This run will focus on effects of plasma shaping. The scans we need to do are: a. scan kappa for otherwise identical discharges. - this should be done at two densities, the first at the lowest feasible density to explore the "neo-Alcator" regime (nebar = .5e20 if possible), the second at a higher density where we have previously seen no density dependence (nebar = 1.5e20). b. scan kappa at fixed q - use the same two densities Toroidal Field: 5.3 Plasma Current: 0.4-0.8 MA Working gas species: D2 Shot sequence plan 1. scan kappa from 0.9 to 1.5 at Ip = .5 MA, ne = 0.5 x 1020 - limited 2. scan kappa from 0.9 to 1.5 at Ip = .5 MA, ne = 1.5 x 1020 - limited 3. scan kappa from 0.9 to 1.5 at q95 = 4, (Ip ~ .45 to .8 MA) ne = 0.5 x 1020 - limited 4. scan kappa from 0.9 to 1.5 at q95 = 4, (Ip ~ .45 to .8 MA) ne = 1.5 x 1020 - limited (Assuming ~5 kappa's for each these scans, kappa = [.9, 1.0, 1.1, 1.3, 1.5] => 20 good shots)
May 16 1995 08:41:48:110AM		Martin Greenwald	Run Plan for Ohmic Confinement Studies - 950516 ----------------------------------------------- Test possible explanations for the observed difference in confinement scaling between C-Mod and Alcator C. This run will focus on effects of plasma shaping. The scans we need to do are: a. scan kappa for otherwise identical discharges. - this should be done at two densities, the first at the lowest feasible density to explore the "neo-Alcator" regime (nebar = .5e20 if possible), the second at a higher density where we have previously seen no density dependence (nebar = 1.5e20). b. scan kappa at fixed q - use the same two densities Toroidal Field: 5.3 Plasma Current: 0.4-0.8 MA Working gas species: D2 Shot sequence plan 1. scan kappa from 0.9 to 1.5 at Ip = .5 MA, ne = 0.5 x 1020 - limited 2. scan kappa from 0.9 to 1.5 at Ip = .5 MA, ne = 1.5 x 1020 - limited 3. scan kappa from 0.9 to 1.5 at q95 = 4, (Ip ~ .45 to .8 MA) ne = 0.5 x 1020 - limited 4. scan kappa from 0.9 to 1.5 at q95 = 4, (Ip ~ .45 to .8 MA) ne = 1.5 x 1020 - limited (Assuming ~5 kappa's for each these scans, kappa = [.9, 1.0, 1.1, 1.3, 1.5] => 20 good shots)
May 16 1995 08:40:52:210AM	950516003	Martin Greenwald	Run Plan for Ohmic Confinement Studies - 950516 ----------------------------------------------- Test possible explanations for the observed difference in confinement scaling between C-Mod and Alcator C. This run will focus on effects of plasma shaping. The scans we need to do are: a. scan kappa for otherwise identical discharges. - this should be done at two densities, the first at the lowest feasible density to explore the "neo-Alcator" regime (nebar = .5e20 if possible), the second at a higher density where we have previously seen no density dependence (nebar = 1.5e20). b. scan kappa at fixed q - use the same two densities Toroidal Field: 5.3 Plasma Current: 0.4-0.8 MA Working gas species: D2 Shot sequence plan 1. scan kappa from 0.9 to 1.5 at Ip = .5 MA, ne = 0.5 x 1020 - limited 2. scan kappa from 0.9 to 1.5 at Ip = .5 MA, ne = 1.5 x 1020 - limited 3. scan kappa from 0.9 to 1.5 at q95 = 4, (Ip ~ .45 to .8 MA) ne = 0.5 x 1020 - limited 4. scan kappa from 0.9 to 1.5 at q95 = 4, (Ip ~ .45 to .8 MA) ne = 1.5 x 1020 - limited (Assuming ~5 kappa's for each these scans, kappa = [.9, 1.0, 1.1, 1.3, 1.5] => 20 good shots)
May 16 1995 09:40:21:200AM	950516005	Martin Greenwald	First Attempt Good Shot Ip = .52 ne0_YAG = 2. nebar_07 = kappa = 1.2
May 16 1995 10:03:29:240AM	950516006	Martin Greenwald	Good Shot Ip = .52 ne0_YAG = 2. nebar_07 = 1.8 kappa = 1.2
May 16 1995 10:33:32:270AM	950516007	Martin Greenwald	Air switch problem? - no shot
May 16 1995 12:13:00:430PM	950516007	Martin Greenwald	Run Abandoned on account of raining tiles!

Physics Operator Comments

Engineering Operator Comments
Shot	Time	Type	Status	Comment
1	07:45:06:690AM	Test	Ok	scanner test
2	08:05:04:190AM	Test	Ok	scanner test
3	08:37:46:650AM	Test	Ok
4	09:12:38:890AM	Test	Ok
5	09:31:18:860AM	Plasma	Ok
6	09:56:28:550AM	Plasma	Ok
7	10:16:39:040AM	Plasma	Bad	type 3 fault on all supplies except tmx's