Miniproposals

Miniproposal: 046 Date Filed: 4/7/1994 Title: Ohmic Confinement First Author: Martin Greenwald Session Leader: Martin Greenwald (shots 1-20)

Engineering Operator Run Comment

ohmic transport

Session Leader Plans

Physics Operators Plans

Session Leader Summaries

Entered: Jul 7 2004 03:49:10:790PM

Author: To Be Determined

Run of 940603 Greenwald, Goetz Plan: Ohmic Confinement Run - Fill in data base at lower current and kappa - D2, limited - allowing comparison w/H2 data from 93 - run "Alcator C" like plasmas if possible Summary: A good fraction of the run plan was accomplished. Startup was slightly rockier than the previous couple of days and a power supply problem took about 2 hours to diagnose and fix. Good shots - suitable for analysis are listed below. We got most of the kappa scan, only missing kappa = 1. As we discovered last summer, it is hard to control the density for limiter discharges. The following are good shots for transport analysis: Shot Ip Kappa nebar 005 .8 1.5-1.6 1.3-1.7 006 .8 1.3-1.6 1.4-1.6 007 .8 1.3-1.5 1.4-1.6 012 .8 1.4-1.5 1.2-1.6 013 .8 1.4 1.2-1.5 014 .8 1.45 1.1-1.7 015 .6 1.4 1.0-1.7 016 .4 1.3 0.7-1.1 017 .4 1.35 0.7-1.2 018 .4 1.2 0.8-1.1 019 .6 1.25-1.3 0.9-1.1 020 .8 1.25 1.1-1.4

Physics Operator Summaries

Entered: Jul 7 2004 04:36:51:677PM

Author: To Be Determined

Physics operator summary for 940603 EO: Bertilino/Daigle PO: Goetz SL: Greenwald Run 940603 was in support of Mini-Proposal #046 - Ohmic Transport. This run was intended to extend the range of the Ohmic confinement database. The parameter range to be explored was: 1 < kappa < 1.5; 0.4 < Ip < 0.8; 1 < nebar < 2x10^20; and 0.17 < a < .22. The run started with a reload of shot 940601021 which was a shot with 0.8MA, nebar = 1.2x10^20 and kappa = 1.5. In the end discharges with 1.2 < kappa < 1.5 and 0.4 < Ip < 0.8 MA were obtained and some holes in the database were filled. The pulse length was extended to 1.0 sec to allow more time for good data acquisition. The gain switches in the IP controller were changed to 1.0 sec, the IC_EF1's were extended to 1.25 sec, and the IC_EF2's were extended to 1.3 sec. The invert times for the PF supplies were moved to 1.4 sec and the time for TF invert was set at 1.1 sec. Another slow start to the day. The run started Dud-fizzle-disruptive plasma- Dud. After this, RF assist was called for at a level of 10kW. The next few shots show a feature on the Halpha trace indicative of bumping into something on the outboard side of the machine. Shot 008 did not make it through this bump. Most of the rest of the shots also had this feature but made it through. The fill pressure was raised to try and slow the current rise but this remedy obviously was not a remedy. Only on the last three or so shots was this feature not present in the current rises. Kappa was changed by using the IC_EF1 controllers. The KAPPA predictor was working and reliably determining kappa. This controller was not turned on though. It is recommended that a controller built of the EF1's should be turned soon. Estimates for the changes made in EF1 are: @ 0.4 MA a change of +1250A gives a change of -.15 in kappa @ 0.6 MA a change of +2000A gives a change of -.1 in kappa @ 0.8 MA a change of +3000A gives a change of -.2 in kappa Also RCUR was moved in as the current was decreased to help out with the elongation. Segment 2 was loaded with the controllers from Segment 1 and on Shot 017, Segment 2 was turned on at 1.1 sec. For Shot 018, the P's were made identical. All seemed to work well with the segment switching as nothing really bad happened. Care should be taken to make sure that the things that are not supposed to change over segments don't. If you do not want segment switching do not use a shot after 940603017 without turning off segment 2. Engineering today: Blown fuse after shot 009 in the OH2L supply and the same fuse blew on the precharge for shot 010 resulting in the loss of the shot. The repair turned out to be a bad gate drive board (the gate was on at all times). While this repair was being affected, the Ross relays were out and EF1L became too warm. Total lost time due to repair and recool was approximately two hours. Scorecard: 20 shots = 14 plasmas + 3 fizzles + 2 duds + 1 power supply dud Shot summary for Run 940603 Reload of 940601021 Changes: Draw Ip flattop to 1.0 sec Draw Ip controller gain switches to 1.0 sec Extend IC_EF1U and IC_EF1L to 1.25 sec Extend IC_EF2U and IC_EF2L to 1.3 sec Moved TF invert time to 1.1 sec and all PF invert times to 1.4 sec Shot change result ____ _____ ______ 1 see above dud 2 IC_EF4 = -1020A fizzle 3 P_0=1.0e-5 plasma 4 no changes dud 5 IC_EF4=-1015A; RF assist of 10-20kW at breakdonw plasma 6 IC_EF1's to 2000A at 0.4sec; RCUR to 0.66 after 0.4 sec plasma 7 lower PULSE_GAS_3 early; add second pulse to PULSE_GAS_1 at 0.5; IC_EF1's to 2250 @ 0.4 and 1750 @ 1.0 plasma 8 raise PULSE_GAS_3 late; add third pulse to PULSE_GAS_1 at 0.7 ICEF1's to 1250A @ 0.4 and 3000A @ 1.25 fizzle 9 no changes - try again plasma 10 P_0=1.1e-5; less PULSE_GAS_3 early; IC_EF1's to 500A @ 0.4 ps dud 11 IC_EF4 to -990A; fizzle detector off at 1.5 and reset fizzle detector threshold to 51.3 ka ( 75 mv) fizzle 12 IC_EF4 back to -1015A plasma 13 IC_EF4=-1025; IC_EF1's=3750A @ 1.2; PULSE_GAS_1 third pulse decreased; PULSE_GAS_3 lowered early plasma 14 lower PULSE_GAS_3 early and raise to 50V @ 0.5sec plasma 15 IP=-600000; IC_EF1'S = 3000A @ 1.2; plasma 16 IP=-390000; IC_EF1's to 2000@1.2 and 750 @0.4; PULSE_GAS_3 raised late plasma 17 RCUR=0.65; IC_EF1's =2500 @ 1.2 and 500 @ 0.4; turn on segment 2 (which was loaded with segment 1); raise PULSE_GAS_3 early and lower late plasma 18 IC_EF1's = 1000 @ 0.4 and 3750 @ 1.2; RCUR=0.645; raise PULSE_GAS_3 early and lower late plasma 19 IP=-600000; IC_EF1's = 5000A @ 1.2 and 250 @ 0.4; RCUR=0.655 plasma 20 IP=-800000; IC_EF1's = 6500A @ 1.2 and 5000A @ 0.7; RCUR=0.66 a little more PULSE_GAS_3 plasma

Session Leader Comments

Physics Operator Comments
Jun 3 1994 08:33:23:430AM		John Goetz	RUN 940603 Mini-Proposal 046 -- Ohmic Transport This run is designed to extend the range of the Ohmic confinement database. The parameter range to be covered: 1 < kappa < 1.5 0.4 < Ip < 0.8 1 < nebar < 2 X 10^20 .17 < a < .22 The plan is to scan density and current at each kappa consistent with the q limit. The run will start with a reload of 940601021 (no changes).
Jun 3 1994 09:25:22:850AM	940603001	John Goetz	For Shot 940603001: Draw Ip out to 1.0 sec Draw Ip controller gain switches to 1.0 sec Extend IC_EF1U and IC_EF1L to 1.25 sec Extend IC_EF2U and IC_EF2L to 1.3 sec Move TF invert time to 1.1 sec and all PF invert times to 1.4 sec Shot 940603001: Dud Bz a little too positive? For Shot 940603002: lower IC_EF4 to -1020A
Jun 3 1994 09:39:49:430AM	940603002	John Goetz	For Shot 940603001: Draw Ip out to 1.0 sec Draw Ip controller gain switches to 1.0 sec Shot 940603002: Fizzle Breakdown at .006; Halpha until .05; nel = 6x10^18 a few bounces here and there For Shot 940603003: lower P_0 to 1.0e-5
Jun 3 1994 09:48:06:290AM	940603003	John Goetz	For Shot 940603001: Draw Ip out to 1.0 sec Draw Ip controller gain switches to 1.0 sec Shot 940603003: Plasma - very disruptive after .08 maybe too much gas from inner wall? puff? For Shot 940603004: no changes - try again
Jun 3 1994 10:05:51:800AM	940603004	John Goetz	For Shot 940603001: Draw Ip out to 1.0 sec Draw Ip controller gain switches to 1.0 sec Shot 940603004: Dud Bz takes a negative jump right at the nominal breakdown time For Shot 940603005: IC_EF4=-1015A to get BZ a bit more positive RF assist at breakdown - 10 or 20 kW
Jun 3 1994 10:35:32:110AM	940603005	John Goetz	Shot 940603005: Plasma Ip=.80; lasts until 1.2 sec; rampdown at 1.0sec lots of injections inner gap from 0.5sec on diverts with x-point on inner nose no RF heating so lower beta and a different plasma than 940601021 For Shot 940603006: IC_EF1's to 2000A @ 0.4sec RCUR to 0.66 after 0.4 sec
Jun 3 1994 10:54:54:940AM	940603006	John Goetz	Shot 940603006: Plasma Ip=.80; successful rampdown at 1.0sec no inner gap until after 0.8 kappa ramps from 1.2 @ 0.4 to 1.5 @ 1.0 sec For Shot 940603007: IC_EF1's to 2250A @ 0.4sec and 1750 @ 1.0 to try and hold kappa at 1.4 add second pulse to PULSE_GAS_1 at 0.5 sec ( .01 sec wide ) lower PULSE_GAS_3 early to try and get a density ramp
Jun 3 1994 11:13:28:960AM	940603007	John Goetz	Shot 940603007: Plasma Ip=.80; successful rampdown at 1.0sec no inner gap until after 0.8 kappa ramps from 1.2 @ 0.4 to 1.5 @ 1.0 sec For Shot 940603008: IC_EF1's to 1250A @ 0.4sec and 3000 @ 1.25 to try and hold kappa at 1.4 add third pulse to PULSE_GAS_1 at 0.7 sec ( .01 sec wide ) lower PULSE_GAS_3 early to try and get a density ramp and raise late to get a better density ramp
Jun 3 1994 11:32:58:900AM	940603008	John Goetz	Shot 940603008: Fizzle - lasts until .035 - hits something at .016 For Shot 940603009: no changes - try again
Jun 3 1994 11:51:07:030AM	940603009	John Goetz	Shot 940603009: Plasma Disrupts at 1.16 sec kappa ramp better, i.e. flatter density has bump near 0.5 For Shot 940603010: IC_EF1's to 500A @ 0.4sec less PULSE_GAS_3 early to get a better density ramp P_0=1.1e-5 to try and slow current rise
Jun 3 1994 12:07:35:820PM	940603010	John Goetz	Shot 940603010: Power supply failure - no commutation supplies went Fuse blown on shot 009 disruption blew again - maybe indicative of a bad SCR For Shot 940603011: scatterplot shows Bz too negative throughout breakdown, probably the cause of the current rise trouble IC_EF4 to -990A
Jun 3 1994 02:07:31:520PM	940603011	John Goetz	Shot 940603011: turns out it was a bad gate board in the OH2L supply - the gate was always on. fizzle - Bz too positive For Shot 940603012: IC_EF4 back to -1015A
Jun 3 1994 02:34:14:350PM	940603012	John Goetz	Shot 940603012: Plasma - Ip=.81 kappa flat from 0.6 to 1.0 sec at about 1.5 not much of a density ramp over this time breakdown early - Bz a little positive - hit something at .028 For Shot 940603013: IC_EF4 to -1025A IC_EF1's to 3750A @ 1.2 to lower elongation lower PULSE_GAS_3 early to get a better density ramp third PULSE_GAS_1 lowered to 90V
Jun 3 1994 02:54:58:240PM	940603013	John Goetz	Shot 940603013: Plasma - Ip=.81 kappa flat from 0.6 to 1.0 sec at about 1.44 not much of a density ramp over this time For Shot 940603014: lower PULSE_GAS_3 early and raise to 50V @ 0.5 sec to get a better density ramp
Jun 3 1994 03:05:54:760PM	940603014	John Goetz	Shot 940603014: Plasma - Ip=.81 - disrupts @ 1.19 kappa flat from 0.6 to 1.0 sec at about 1.44 small density ramp up and down at this time For Shot 940603015: IP=-600000 IC_EF1's = 3000 @ 1.2 (try to keep elongation the same as 014) draw a KAPPA of 0.2 @ 1.0 to test controller
Jun 3 1994 03:27:15:980PM	940603015	John Goetz	Shot 940603015: Plasma - Ip=.63 - disrupts @ 1.17 kappa from 1.4 at 0.5 to 1.45 at 1.0 sec good density ramp For Shot 940603016: IP=-390000 IC_EF1's = 2000 @ 1.2 and 750 @ 0.4 (try to keep elongation the same as 014) raise PULSE_GAS_3 up late
Jun 3 1994 03:53:47:440PM	940603016	John Goetz	Shot 940603016: Plasma - Ip=.4 - disrupts @ 71 kappa from 1.3 from 0.4 onward too much density - too heavy on the gas puff For Shot 940603017: IC_EF1's = 2500 @ 1.2 and 500 @ 0.4 raise PULSE_GAS_3 early and lower it late remove third pulse on PULSE_GAS_1 RCUR = 0.65 from 0.4 onward load segment 2 with segment 1 and turn on at 1.1 sec
Jun 3 1994 04:07:38:160PM	940603017	John Goetz	Shot 940603017: Plasma - Ip=.4 - disrupts @ 1.1 kappa from 1.35 from 0.4 onward too much density - too heavy on the gas puff after 0.8 For Shot 940603018: IC_EF1's = 3750 @ 1.2 and 1000 @ 0.4 raise PULSE_GAS_3 early and lower it late RCUR = 0.645 from 0.4 onward
Jun 3 1994 04:31:07:800PM	940603018	John Goetz	Shot 940603018: Plasma - Ip=.42 - almost makes it down kappa from 1.2 @ 0.5 to 1.15 @ 1.0 density good - nebar ~ 1x10^20 For Shot 940603019: IP=-600000 IC_EF1's = 5000 @ 1.2 and 250 @ 0.4 RCUR = 0.655 from 0.4 onward
Jun 3 1994 04:57:23:770PM	940603019	John Goetz	Shot 940603019: Plasma - Ip=.62 - almost makes it down kappa from 1.3 @ 0.65 to 1.2 @ 1.0 density good - nebar ~ 1.1x10^20 For Shot 940603020: IP=-800000 IC_EF1's = 6500 @ 1.2 and 5000 @ 0.7 RCUR = 0.66 from 0.4 onward a little bit more PULSE_GAS_3
Jun 3 1994 05:12:34:350PM	940603020	John Goetz	Shot 940603020: Plasma - Ip=.80 - almost makes it down kappa = 1.25 from 0.5 to 1.0 density good - nebar ~ 1.0x10^20 to 1.5x10^20

Engineering Operator Comments
Shot	Time	Type	Status	Comment
1	09:13:13:530AM	Plasma	Ok	no faults
2	09:28:03:250AM	Plasma	Ok	no faults
3	09:39:55:010AM	Plasma	Ok	no faults
4	09:51:54:370AM	Plasma	Ok	no faults
5	10:07:38:720AM	Plasma	Ok	no faults
6	10:35:11:740AM	Plasma	Ok	oh1 comm fault in inversion
7	10:54:37:730AM	Plasma	Ok	no faults
8	11:13:34:880AM	Plasma	Ok	no faults
9	11:29:02:130AM	Plasma	Ok	comm fail oh1 and oh2s after disruption
10	11:52:37:050AM	Plasma	Bad	oh2l failed early
11	01:54:35:460PM	Plasma	Ok	dud no faults.
12	02:09:12:780PM	Plasma	Ok	comm fault oh2's ef1's oh1.
13	02:30:07:870PM	Plasma	Ok	comm faults oh1 oh2u
14	02:48:57:030PM	Plasma	Ok	com fault oh1
15	03:06:51:270PM	Plasma	Ok	oh1 com. fault
16	03:27:00:220PM	Plasma	Ok	NO faults
17	03:48:53:990PM	Plasma	Ok	oh1 com. fault
18	04:13:14:470PM	Plasma	Ok	No faults
19	04:32:08:360PM	Plasma	Ok	No faults.
20	04:57:56:690PM	Plasma	Ok	No faults.