Miniproposals

Miniproposal: 267 Date Filed: 4/4/2000 Title: Dependence of SOL Fluctuations and Particle Transport on Collisionality First Author: Brian Labombard Session Leader: Brian Labombard (shots 1-34)

Engineering Operator Run Comment

Begin with Power System Tests after Bus Reversal and Long Pulse Instrume

Session Leader Plans

Physics Operators Plans

Session Leader Summaries

Physics Operator Summaries

Entered: Jul 7 2004 04:37:12:567PM

Author: To Be Determined

MP 267 Dependence of SOL Fluctuations and Particle Transport on Collisionality now with reversed (positive) toroidal field and plasma current Session Leader: Brian Labombard Physics Operator: Joseph Snipes Engineer in Charge: Gary Dekow overnight discharge cleaning in D_2, stopping 2 hours before the run. Run begins at 9:00 and ends at 17:00. Power system setup as on 1001012017 Gas setup - fill B-top with 6 psi of D2 Hybrid enabled fill B-side lower with 1 psi of Ar Hybrid enabled fill B-side upper with 35 psi of D2 Hybrid DISABLED (for ECDC) fill C-side with 30 psi of D2 Hybrid enabled leave J-bottom as is Hybrid DISABLED The following gate valves should be enabled, assuming no vacuum problems: ECE, VUV, NPA (aka Beast) This will be an ohmic run; RF is not required though it may do coupling studies The purpose of these experiments is to explore the dependence of SOL fluctuation characteristics and attendent cross-field particle transport on the collisionality of the SOL. The key diagnostics which must be operational for this study are: (a) A-port and F-port scanning probes operated in a fluctuation mode (The A-port probe will be used in both a spatially scanning and a fixed position mode.), (b) divertor probes operated in a fluctuation mode, (c) fast visible diodes viewing helium puffed from the A/B limiter capillary, (d) tangential Ly-alpha diode array, (e) limiter particle flux probes, and (f) edge thomson scattering. Day 1: Fine density scan at fixed plasma current (0.8 MA) and toroidal field (5.3 T). Start with a reload of 1001012017. Shot 1-3 NL01 = 1 x 10^20 m^-2 Setup equilibrium and FSP/ASP target Begin density scan with two shots at each density. Alternate between A-port probe in scanning and fixed location modes Shot 4,5 NL01 = 1.0 6,7 NL01 = 0.9 8,9 NL01 = 0.8 10,11 NL01 = 0.7 12,13 NL01 = 0.6 14,15,16 NL01 = 1.1 17,18 NL01 = 1.2 19,20 NL01 = 1.3 21,22 NL01 = 1.4 repeat shots as needed to get good diagnostic data. Summary: The first part of the day was spent on power supply tests after work had been done on the power supplies earlier in the week and the busbars had been inverted to give positive TF and Ip. The last half of the run was spent trying to get plasmas. Shot 22: Copied shot 1001012017 and inverted all appropriate waveforms for reversed field. Reversed signs on Br0, RCUR, and CLEARIN offsets. Changed the TF current request in both segments 1 and 2 to be constant at 150 kA. Dud. Fields way off as expected. Shot 23: Increased Br0 by 2 mT to +0.5 mT. Dropped OH1 current by 1 kA to 19 kA before t=0. Try again. Fizzle! Field considerably better. Shot 24: Delay due to problems with cooling of the central column. Willy fixed the problem. Increased EF4 current by 20 A to 1310 A before t=0. Fizzle! Later breakdown. Shot 25: Return to EF4 of 1290 A. Increase Br0 offset by 0.5 mT to 1 mT. Increase pre-puff by 4 ms to 25 ms duration. Changed RCUR offset to -8000 as on 1000329002. Dud! Shot 26: Reduced pre-puff to 19 ms duration. Set Br0 to 0. Dud again! Shot 27: Try returning to RCUR offset of -5500. One more time. . . Dud! Shot 28: Reload shot 23. Apparently I forgot to load into model shot 23 since Br0 was set to 0 and prepuff was 19 ms. Dud again! Shot 29: Reload shot 23 once more. Dud! Shot 30: Increase Br0 by 0.5 mT to 1.0 mT. Increase OH1 current by 100 A to 19100 A. Increase pre-puff by 2 ms to 23 ms duration. Dud! Shot 31: Increased EF4 current by 25 A to 1315 A. Increased pre-puff by 4 ms to 27 ms duration. Fizzle! Shot 32: Increased EF4 current by 15 A to 1330 A. Slightly better fizzle. Shot 33: Increased EF4 current by 15 A to 1345 A. Slightly worse fizzle. Shot 34: Reduced EF4 current to 1325 A. Increased OH1 voltage from 10 to 15 ms up to 200 V at 10 ms and 150 V at 15 ms. Fizzle!

Session Leader Comments
Nov 1 2000 09:51:29:827AM		Brian Labombard	MP#267 - reversed field "Dependence of SOL Fluctuations and Particle Transport on Collisionality" - reversed field, Day 1 Session Leader - B. LaBombard Phys Op - J. Snipes ============================================================================== Overall objectives of MP#267: "The purpose of these experiments is to explore the dependence of SOL fluctuation characteristics and attendant cross-field particle transport on the collisionality of the SOL." Reason for today's run: Reversed field/current allows some important measurements to be made on particle transport in the SOL and the associated levels of plasma turbulence. From a series of shots over ~2 run days we hope to do the following: (1) get data on SOL particle transport (using Ly-alpha diag.) in reversed field. Does the field direction affect the 'scaling' of Deff with collisionality? (2) get data on in-out asymmetries. The outer divertor conditions should change in reversed B. This may impact (1) through changes in the sheath conditions at the divertor plate (e.g., affecting the propagation velocity of the 'blobs' if they somehow involve the 'sheath impedance' via a theory such as that outlined recently by S. Krasheninnikov) (3) get data on field-reversed C2D4 plumes. ExB should now carry the plume away from the probe shaft, resulting in plumes that may be easier to interpret. The 'reversed flows' associated with low collisionality near the separatrix should now become 'normal flows' with reversed B. This should be interesting for the plumes. The magnitude of Er in reversed B is of interest also. (4) get fluctuation data from scanning probe and fast diodes systems. Is the SOL plasma fluctuation character the same in reversed B? Today's run was to cover the Day 1 plan outlined in MP#267: Day 1 (today): Fine density scan at fixed plasma current (0.8 MA) and toroidal field (5.3 tesla).

Physics Operator Comments
Nov 1 2000 01:00:00:903PM	1001101022	Joseph Snipes	Shot 22: Copied shot 1001012017 and inverted all appropriate waveforms for reversed field. Reversed signs on Br0, RCUR, and CLEARIN offsets. Changed the TF current request in both segments 1 and 2 to be constant at 150 kA. Dud. Fields way off as expected.
Nov 1 2000 01:24:17:013PM	1001101023	Joseph Snipes	Shot 23: Increased Br0 by 2 mT to +0.5 mT. Dropped OH1 current by 1 kA to 19 kA before t=0. Try again. Fizzle! Field considerably better.
Nov 1 2000 02:02:30:937PM	1001101024	Joseph Snipes	Shot 24: Delay due to problems with cooling of the central column. Willy fixed the problem. Increased EF4 current by 20 A to 1310 A before t=0. Fizzle! Later breakdown.
Nov 1 2000 02:18:31:140PM	1001101025	Joseph Snipes	Shot 25: Return to EF4 of 1290 A. Increase Br0 offset by 0.5 mT to 1 mT. Increase pre-puff by 4 ms to 25 ms duration. Changed RCUR offset to -8000 as on 1000329002. Dud!
Nov 1 2000 02:52:56:030PM	1001101026	Joseph Snipes	Shot 26: Reduced pre-puff to 19 ms duration. Set Br0 to 0. Dud again!
Nov 1 2000 02:50:40:077PM	1001101027	Joseph Snipes	Shot 27: Try returning to RCUR offset of -5500. One more time. . . Dud!
Nov 1 2000 03:25:25:653PM	1001101028	Joseph Snipes	Shot 28: Reload shot 23. Apparently I forgot to load into model shot 23 since Br0 was set to 0 and prepuff was 19 ms. Dud again!
Nov 1 2000 03:41:11:513PM	1001101029	Joseph Snipes	Shot 29: Reload shot 23 once more. Dud!
Nov 1 2000 03:56:14:310PM	1001101030	Joseph Snipes	Shot 30: Increase Br0 by 0.5 mT to 1.0 mT. Increase OH1 current by 100 A to 19100 A. Increase pre-puff by 2 ms to 23 ms duration. Dud! Shot was aborted for some reason!
Nov 1 2000 04:09:40:170PM	1001101031	Joseph Snipes	Shot 31: Increased EF4 current by 25 A to 1315 A. Increased pre-puff by 4 ms to 27 ms duration. Fizzle!
Nov 1 2000 04:46:47:047PM	1001101032	Joseph Snipes	Shot 32: Increased EF4 current by 15 A to 1330 A. Slightly better fizzle.
Nov 1 2000 04:55:22:340PM	1001101033	Joseph Snipes	Shot 33: Increased EF4 current by 15 A to 1345 A. Slightly worse fizzle.
Nov 1 2000 05:03:20:950PM	1001101033	Joseph Snipes	Shot 34: Reduced EF4 current to 1325 A. Increased OH1 voltage from 10 to 15 ms up to 200 V at 10 ms and 150 V at 15 ms. Fizzle!

Engineering Operator Comments
Shot	Time	Type	Status	Comment
1	09:13:34:640AM	Test	Ok	EF4 Forward Bridge
2	09:23:27:357AM	Test	Ok	EF4 Reverse Bridge Test
3	09:34:48:250AM	Test	Ok	EF2L Test
4	09:43:01:420AM	Test	Ok	EF2U Test
5	09:52:20:000AM	Test	Ok	EFC Test
6	10:01:13:403AM	Test	Ok	EF3 Test
7	10:09:18:640AM	Test	Ok	OH2U Forward Bridge
8	10:18:54:467AM	Test	Ok	OH2U Reverse Bridge
9	10:27:12:903AM	Test	Ok	OH2L Forward Bridge Test
10	10:35:13:250AM	Test	Ok	OH2L Reverse Bridge
11	10:42:13:373AM	Test	Ok	OH1 Forward Bridge Test
12	10:49:19:280AM	Test	Ok	OH1 Reverse Bridge Test
13	10:57:42:950AM	Test	Ok	EF1U Forward Test
14	11:05:41:890AM	Test	Ok	EF1U Reverse Test
15	11:14:49:217AM	Test	Ok	EF1L Forward Test
16	11:22:11:857AM	Test	Ok	EF1L REverse Test
17	11:32:38:797AM	Test	Ok	TF at 50KAMPS
18	11:41:31:343AM	Test	Ok	TF at 100KA
19	11:50:31:543AM	Test	Bad	TF did not fire
20	12:02:12:513PM	Test	Ok	TF did not fire
21	12:11:50:247PM	Test	Ok	TF at 150KA
22	12:46:25:467PM	Plasma	Ok	All Systems Fired
23	01:06:26:607PM	Plasma	Ok
24	01:48:43:140PM	Plasma	Ok
25	02:09:56:560PM	Plasma	Ok
26	02:29:45:843PM	Plasma	Ok
27	02:46:44:843PM	Plasma	Ok
28	03:06:14:530PM	Plasma	Ok
29	03:27:37:343PM	Plasma	Ok
30	03:45:05:437PM	Plasma	Ok
31	04:07:58:873PM	Plasma	Ok
32	04:25:06:810PM	Plasma	Ok
33	04:44:35:810PM	Plasma	Ok
34	05:01:59:077PM	Plasma	Ok