Miniproposals

Miniproposal: 271 Date Filed: 5/12/2000 Title: Scaling of H-mode pedestal parameters with global plasma parameters First Author: Dmitri Mossessian Session Leader: Dmitri Mossessian (shots 1-19)

Engineering Operator Run Comment

MP271,part2-pedestal parameters scalings with magnetic field and plasma

Session Leader Plans

Physics Operators Plans

Session Leader Summaries

Entered: Jul 7 2004 03:49:24:773PM

Author: To Be Determined

Run summary for 1000907 - MP 271 Pedestal scalings The plan was to start with 1000906018, 5.4 T, 0.8 MA. RF 2.5 - 2 MW, obtain steady state EDA and then scan BT shot to shot from 4.5 to 5.5 T.(higher field was done on 1000906). Then we were going to scan target density shot to shot from 4e19 to 1.4e19, keeping const RF at 2.5 - 2 MW (Ip=0.8MA, Bt=5.4T) The idea was to see if pedestal parameters, gradPe in particular, scale with density at constant plasma current. To get a wide density range we also were going to to control plasma density during H-mode with additional gas puff. Only a small part of the plan was carried out - the Bt scan. Initial conclusion is that none of the pedestal parameters depend on Bt. An attempt to do the density scan was stopped by series of unexplainable disruptions, fizzles and duds. There are 6 usefull shots out of 19, see details below. ECDC between shots did help to keep H/D relatively low. Still, on average H/D was about 10-8%, as opposed to the optimum of 3% Details: ---------------------------------------------------------------------------- 1000907001 mossessian SESSION_LEADER Sep 7 2000 9:29:57:950AM . . . . . . . . . . . . . . . . . . . . Starting field scan. Repeat shot 18 from 09/06: Nice plasma: Ip=0.8 MA, Bt=5.2 T, nl=0.8e20, RF 2.5/2 MW, EDA ---------------------------------------------------------------------------- 1000907002 mossessian SESSION_LEADER Sep 7 2000 9:56:07:436AM . . . . . . . . . . . . . . . . . . . . Lower field for this shot to 4.8 T. Other - same. PLasma: 3 ELM-free-looking H-modes. RF 2.5/2 MW with 2 trips ---------------------------------------------------------------------------- 1000907003 mossessian SESSION_LEADER Sep 7 2000 10:19:36:013AM . . . . . . . . . . . . . . . . . . . . Plasma: Same field (4.8 T), lower RF 2/1.5 MW. Multiple ELM-free. H/D is about 10% - strart ECDC between shots after this shot. ---------------------------------------------------------------------------- 1000907004 mossessian SESSION_LEADER Sep 7 2000 10:26:59:996AM . . . . . . . . . . . . . . . . . . . . Plasma: 4.8 T, after ECDC H/D is at 6% at the beginning of the shot, rising to 10% with RF. First H-mode is EDA, then 2 ELM-free For next shot: go to 4.5 T, other - same. ECDC between shots ---------------------------------------------------------------------------- 1000907005 mossessian SESSION_LEADER Sep 7 2000 10:44:33:390AM . . . . . . . . . . . . . . . . . . . . 4.5 T, multiple ELM-free Go back to 5.4 T, start nl scan ---------------------------------------------------------------------------- 1000907008 mossessian SESSION_LEADER Sep 7 2000 12:44:48:700PM . . . . . . . . . . . . . . . . . . . . ELM-free looking (but with QC at 120kHz) at 2.5/2 MW Keep density low, go to 1.5/1 MW ---------------------------------------------------------------------------- 1000907009 mossessian SESSION_LEADER Sep 7 2000 12:45:11:140PM . . . . . . . . . . . . . . . . . . . . ELM-free looking (but with QC at 120kHz) at 1.5/1 MW Try going to lower density ---------------------------------------------------------------------------- 1000907016 mossessian SESSION_LEADER Sep 7 2000 3:58:04:326PM . . . . . . . . . . . . . . . . . . . . Series of disruptions, fizzles and duds after shot 9. Finally, plasma on shot 16, EDA with 2.5/2 MW at 0.9e20 m^-2 Go to higher tagret 1.1e20 for next shot ---------------------------------------------------------------------------- 1000907019 mossessian SESSION_LEADER Sep 7 2000 4:54:08:966PM . . . . . . . . . . . . . . . . . . . . All disruptions after shot 16.

Physics Operator Summaries

Entered: Jul 7 2004 04:37:11:940PM

Author: To Be Determined

PHYSOP SUMMARY FOR 1000907 ENGINEERING SETUP AND RUN PLAN MP271 Pedestal Parameters Scalings with Magnetic Field and Plasma Density Session Leader: D. Mossessian Physics Operator: R. Parker Engineering Operators: B. Cochran/W. Parkin Engineering Setup: Overnight ECDC in D2, stopping 1-2 hours before run. Run begins at 9:00 and ends at 17:00. Power system setup: Same as for 1000906018 (5.4 T, 0.8 MA diverted) Set OH1, OH2U and OH2L fizzle delays at 300ms Set TF fizzle delay at 400 ms Gas setup: B-Top 6 psi D2 Hybrid Enabled B-side lower 1 psi Argon Hybrid Enabled B-side upper leave as is Hybrid DISABLED C-side 30 psi D2 Hybrid Enabled J-bottom leave as is Hybrid DISABLED The following Gate Valves should be ENABLED, assuming no vacuum problems: ECE, VUV DNB Valve DISABLED RUN PLAN: Start with shot 1000906018, a 5.4 T, 0.8 MA, diverted discharge with RF heating starting at 2.5 MW, then stepping down to 2.0 MW after 400 ms. Then, scan field between 4.5 and 5.5 Tesla. Return to 1000906018 and scan target density from 0.4 to 1.4e20 cm-3, with RF as above. We'll attempt to control plasma density during H-Mode with gas puff. RUN SUMMARY The run began well, with the first 5 shots going off as programmed. However, the plan to run ECDC between shots was thwarted by a faulty shutter on a bolometer. This was fixed after shot 3, and ECDC remained in use between shots for the rest of the run. As in previous runs, it was successfully used to reduce the H/D ratio. Bob Granetz replaced R. Parker for shots 6-11. Shots 6,7,10 and 11 disrupted, while shots 8 and 9 produced useful data. High disruptivity plagued the rest of the run, with only shot 16 avoiding a major disruption. The disruptions were evidently caused by a Moly injection, but the cause of the injection was not clear. Overall, a difficult day with a disappointing number of useful shots. A minor delay was caused by the faulty shutter, but a more significant delay was caused by an OH2 U power supply problem. This occured on shot 13, resulting in the only fizzle of the day, and led to a delay of over 1 hour during which time 3 fuses were replaced. Scorecard: 19 shots, 1 power supply test, 1 fizzle, 1 dud and 8 major disruptions

Session Leader Comments
Sep 7 2000 09:15:23:107AM		Dmitri Mossessian	MP 271 - Pedestal scalings. We'll try to do filed and density scans today
Sep 7 2000 09:29:57:950AM	1000907001	Dmitri Mossessian	Starting field scan. Repeat shot 18 from 09/06: Nice plasma: Ip=0.8 MA, Bt=5.2 T, nl=0.8e20, RF 2.5/2 MW, EDA
Sep 7 2000 09:56:07:437AM	1000907002	Dmitri Mossessian	Lower field for this shot to 4.8 T. Other - same. 3 ELM-free-looking H-modes. RF 2.5/2 MW with 2 trips
Sep 7 2000 10:19:36:013AM	1000907003	Dmitri Mossessian	Same field (4.8 T), lower RF 2/1.5 MW. Multiple ELM-free. H/D is about 10% - strart ECDC between shots after this shot.
Sep 7 2000 10:26:59:997AM	1000907004	Dmitri Mossessian	4.8 T, after ECDC H/D is at 6% at the beginning of the shot, rising to 10% with RF. First H-mode is EDA, then 2 ELM-free For next shot: go to 4.5 T, other - same. ECDC between shots
Sep 7 2000 10:44:33:390AM	1000907005	Dmitri Mossessian	4.5 T, multiple ELM-free Go back to 5.4 T, start nl scan
Sep 7 2000 11:06:11:780AM	1000907006	Dmitri Mossessian	EDA at 2.5 MW disrupted at .9 sec. Go to 5e19 m^-2 for next shot
Sep 7 2000 12:44:48:700PM	1000907008	Dmitri Mossessian	ELM-free looking (but with QC at 120kHz) at 2.5/2 MW Keep density low, go to 1.5/1 MW
Sep 7 2000 12:45:11:140PM	1000907009	Dmitri Mossessian	ELM-free looking (but with QC at 120kHz) at 1.5/1 MW Try going to lower density
Sep 7 2000 12:45:45:920PM	1000907010	Dmitri Mossessian	Density a little lower. Disruptet after 1st ELM-free Go to 9e19 target, 2.5/2 MW
Sep 7 2000 03:58:04:327PM	1000907016	Dmitri Mossessian	Series of disruptions, fizzles and duds after shot 9. Finally, plasma on shot 16, EDA with 2.5/2 MW Go to higher tagret 1.1e20 for next shot
Sep 7 2000 04:54:08:967PM	1000907019	Dmitri Mossessian	All disruptions after shot 16.

Physics Operator Comments
Sep 7 2000 09:32:51:640AM	1000907001	Ron Parker	First shot today ran as programmed, with a slight field ramp from 5.4 to 5.2 T. There is no ECDC between shots, as the Z bolo shutter is not working. It should be fixed for shot 3 or 4.
Sep 7 2000 09:43:44:390AM	1000907002	Ron Parker	In shot 2, the field was ramped down to 4.8 T (133500 kA). No other changes from shot 1 were made. The shot ran again as programmed. No changes for the next shot. ECDC still not operating and H/D ratio is high, ~10%.
Sep 7 2000 10:12:25:950AM	1000907003	Ron Parker	Shot 3 ran as programmed, with periodic H modes. Cell entry after shot to fix bolo shutter. Bolo shutter is fixed and ECDC has been turned on for 10 minutes prior to next shot which will be delayed about 5 minutes.
Sep 7 2000 10:28:11:170AM	1000907004	Ron Parker	Shot 4 ran well. ECDC now running between shots. Next shot: Field lowered to 4.5 T (125 kA)
Sep 7 2000 10:44:07:437AM	1000907005	Ron Parker	Shot 5 ran well, but periodic injections are limiting H-mode durations. For next shot, the field will be set at 5.4 T (150 kA). H/D still ~ 8%. ECDC between shots continues.
Sep 7 2000 11:00:55:670AM	1000907006	Robert Granetz	I'm substituting for Ron as physics operator for the next 1.5 hours.
Sep 7 2000 11:10:24:983AM	1000907006	Robert Granetz	Shot 06 -- Plasma. Disrupted at t=0.90 s. Looks like it was killed by a brick injected at 0.88 s. One EDA H-mode. Btor=5.3 T. Ip=0.8 MA. Next shot: reduce density to nl_04=0.5e20 m-2 (from 0.7e20). Brian will begin firing the FSP on the next shot, but far out in the SOL. ECDC in D2 is being done between shots.
Sep 7 2000 11:36:07:043AM	1000907007	Robert Granetz	Shot 07 -- Plasma. Disrupted at t=0.73 s. Prad is very high, and starts its rise as soon as the RF turns on. NL_04=0.6e20 m-2 before the H-mode starts. Next shot: no changes. ECDC in D2 is being done between shots.
Sep 7 2000 12:00:18:997PM	1000907008	Robert Granetz	Shot 08 -- Plasma. Good shot. Multiple H-modes. Prf(D+E)=2.6 MW, then 2.0 MW. Target nl_04=0.6-0.7e20 m-2. Next shot: no PCS changes. Raise Prf to 3.0 MW, then 2.0 MW. ECDC in D2 is being done between shots.
Sep 7 2000 12:24:51:297PM	1000907009	Robert Granetz	Shot 09 -- Plasma. Good shot. Target nl_04=0.55-0.7e20 m-2. H/D=5-8%. Multiple H-modes. Next shot: reduce target density further by lowering the pre-programmed valve voltage ECDC in D2 is being done between shots.
Sep 7 2000 12:46:47:200PM	1000907010	Robert Granetz	Shot 10 -- Plasma. Disrupted at t=0.79 s. There was a lot of radiated power on this shot, similar to the previous disruption on shot 07. Target nl_04 decreased a little to 0.35-0.64e20 m-2. Next shot: increase density to nl_04=0.9e20 m-2. ECDC in D2 is being done between shots.
Sep 7 2000 01:07:14:700PM	1000907011	Robert Granetz	Shot 11 -- Plasma. Disrupted at t=0.62 s. Looks like a brick. Target density increased to nl_04=0.9e20 m-2, as desired. The injection occurred before the FSP fired. Ron Parker is back as physics operator now. ECDC in D2 is being done between shots.
Sep 7 2000 01:37:23:530PM	1000907012	Ron Parker	Shot disrupted again, even though RG has left the PO chair. Why? RF? Ar? Probe? Strike point? None of the above? We'll find out if it is any of the first three on shot 13 by 1) moving RF turnon 200 msec later; 2) reducing Ar pulse to 10 ms (it was only 20 ms); 3) keeping the probe stationary. If none of these, we'll move the plasma around.
Sep 7 2000 02:26:33:187PM	1000907013	Ron Parker	Shot 13 was a fizzle, caused by OH2 power supply problems. On inspection 6 blown fuses were found. Repair requires a delay of approximately 1 hour.
Sep 7 2000 03:26:06:937PM	1000907014	Ron Parker	Shot 14 was an OH2 upper test. It turned out that only 3 fuses were blown. After the repair to the fuses, there was an additional delay due to a hung computer. Shot 13 will be a repeat of 13, hopefully without the fizzle.
Sep 7 2000 03:40:38:810PM	1000907015	Ron Parker	Shot was a dud, pressure a bit low, .055 mT, and BZ drifting upwards, -.0015 @ t=0. Pressure will be higher on next shot due ot ECDC and EF4 current decreased by 20 A.
Sep 7 2000 04:01:48:437PM	1000907016	Ron Parker	Shot 16 ran well, no disruption (why?). Next shot: target density increased to 1.1e20.
Sep 7 2000 04:19:32:437PM	1000907017	Ron Parker	Shot 17 disrupted at 0.9 s due to an unidentified injection. Try again on next shot.
Sep 7 2000 04:46:18:747PM	1000907018	Ron Parker	Shot 18 again disrupted. Try again, no changes.
Sep 7 2000 04:54:05:640PM	1000907019	Ron Parker	Same shot, same disruption. No conclusion on cause.

Engineering Operator Comments
Shot	Time	Type	Status	Comment
1	09:13:23:997AM	Plasma	Ok
2	09:33:04:530AM	Plasma	Ok
3	09:51:02:420AM	Plasma	Ok
4	10:17:45:483AM	Plasma	Ok
5	10:36:04:623AM	Plasma	Ok
6	10:59:18:967AM	Plasma	Ok
7	11:20:23:530AM	Plasma	Ok
8	11:48:38:730AM	Plasma	Ok
9	12:11:06:513PM	Plasma	Ok
10	12:34:05:437PM	Plasma	Ok
11	12:55:51:030PM	Plasma	Ok
12	01:19:11:747PM	Plasma	Ok
13	01:41:24:310PM	Plasma	Ok
14	03:04:53:780PM	Test	Ok	oh2U test PLC control
15	03:25:41:700PM	Plasma	Ok
16	03:47:46:700PM	Plasma	Ok
17	04:08:38:717PM	Plasma	Ok
18	04:29:16:890PM	Plasma	Ok
19	04:49:27:403PM	Plasma	Ok