Miniproposals

Miniproposal: 268 Date Filed: 4/7/2000 Title: Conditioning of D-, E-, or J-Port ICRF Antenna First Author: Gerd Schilling Session Leader: Steve Wukitch (shots 1-23)

Engineering Operator Run Comment

MP#268 ICRF Conditioning PO:Wolf SL:Wukitch EO:Fitzgerald/Byford

Session Leader Plans

Physics Operators Plans

Session Leader Summaries

Physics Operator Summaries

Entered: Jul 7 2004 04:37:12:113PM

Author: To Be Determined

Physics Operator's Summary for Tuesday, Sept 26 MP#268 ICRF Conditioning SL: Wukitch PO: wolfe EO: Fitzgerald, Engineering setup: ------------------- Overnight ECDC in D2, stopping 1-2 hours prior to run Run begins at 9:00, and ends at 17:00 Power System as on 1000925002 except EFc voltage to 800V. *Note EFc start time should be -.03 sec (Ian's early zcur control). Gas setup - fill B-top with 6 psi of D2 Hybrid enabled fill B-side lower with 1 psi of Ar Hybrid DISABLED fill B-side upper with 35 psi of D2 Hybrid DISABLED, available 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 DNB is out of commission. Do NOT Enable its gate valve! Run Plan: --------- Start with 0.8MA, diverted shot, nl04=0.9e20, 1cm outer gap. Run J-port, check phasing, impurity injections, heating efficiency Monitor H/D ratio with and without RF; hopefully run enough plasmas and between-shot ECDC to get H/D down below 15%, in preparation for boronization. Results: -------- We began with a reload of seg2 from 1000920022, an 0.8MA SNL shot for which Wukitch had data from the four-strap antenna. We got off to a really bad start, with a large number of duds. Tweaks to gas and ef4 did not get back even a fizzle. After shot 4, we tried ECDC in D2 for 15 minutes, and more field and gas tweaking. This was repeated several times. Nothing helped. The B-top (pre-puff) plenum was pumped and purged. The sparker voltage was increased from 20 ->25kV, which gave visible current rises when the gas came in, but did not produce a breakdown. Finally, after 11 straight duds, we did one more round of ECDC, this time using the B-top valve and plenum instead of B-side upper (Tommy's suggestion). The next shot,#12, with no changes in programing, gave a good breakdown and current rise, and disrupted at 0.35sec with a moly injection. Shot#13, with a minor tweak in seg2 RCUR programing, ran full length. The only other change before shot 12 was to close the VUV gate valve, but this was re-enabled for shot 15 with no deleterious effect. I have no explanation for the duds or their disappearance. It is possible that we cleaned and/or burned away something with the last round of ECDC. It is also possible that there was some contamination in the B-top gas line that was purged through by using it for ECDC. The increased sparker voltage was presumably not responsible, since that was increased several shots earlier. Later in the run (shot 17), we reduced the voltage back to 21.5kV, which still gave a clearly visible current rise when the gas puff comes in. At any rate, the breakdown was rock solid the remainder of the day. We ended with 11 duds and 12 plasmas (including one early disruption on shot#12). H/D ratios were running between .1 and .25, with the high values during the highest power from D&E. J-port got up to about 1MW. There were still some injections coming from it, but perhaps not as bad as before. On the last two shots J4 refused to turn on. John and Rejean were trying to diagnose the problem after the run. There still seems to be no agreement on what the available phase measurements mean. D&E got up to 2-2.5MW combined. Heating efficiency was quite poor, presumably because of the high H/D ratios. H-modes were obtained on the first shot with RF, but none at higher power later in the day. The H/D ratio was determined to be low enough to proceed with boronization. Tomorrow's run is slated for boronization recovery and completion of an ohmic run. I recommend that the RF group be prepared to operate in piggyback mode to evaluate heating from J-port in its present configuration with reduced H/D. Scorecard --------- Duds 11 Fizzles 0 Plasmas 12 (including one .35sec disruption) ------ -- Shots 23

Session Leader Comments

Physics Operator Comments
Sep 26 2000 07:40:38:170AM		Steve Wolfe	Per SL instructions, load seg2 from 1000920022 coldstart at 07:38 all matrices respond.
Sep 26 2000 07:42:25:497AM		Steve Wolfe	Run Plan and Engineering setup for Tuesday, Sept 26 MP#268 ICRF Conditioning SL: Wukitch PO: wolfe Engineering setup: ------------------- Overnight ECDC in D2, stopping 1-2 hours prior to run Run begins at 9:00, and ends at 17:00 Power System as on 1000925002 except EFc voltage to 800V. *Note EFc start time should be -.03 sec (Ian's early zcur control). Gas setup - fill B-top with 6 psi of D2 Hybrid enabled fill B-side lower with 1 psi of Ar Hybrid DISABLED fill B-side upper with 35 psi of D2 Hybrid DISABLED, available 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 DNB is out of commission. Do NOT Enable its gate valve! Run Plan: --------- Start with 800ka, diverted shot, nl04=0.9e20, 1cm outer gap. Run J-port, check phasing, impurity injections, heating efficiency Monitor H/D ratio with and without RF; hopefully run enough plasmas and between-shot ECDC to get H/D down below 15%, in preparation for boronization.
Sep 26 2000 09:08:31:827AM	1000926001	Steve Wolfe	Shot#1: Loaded seg 1 from 1000925026, seg2 from 1000920022 dud. Bz looks negative. Gas looks low. next shot: increase pre-puff to 20msec, see if Bz comes along on its own
Sep 26 2000 09:20:15:543AM	1000926002	Steve Wolfe	Shot#2: increase pre-puff to 20msec, see if Bz comes along on its own another dud? better fix the Bz. next shot: icef4 from -1290->-1270, gas to 23msec
Sep 26 2000 09:35:43:937AM	1000926003	Steve Wolfe	Shot#3: icef4 from -1290->-1270, gas to 23msec another one! What's wrong? Sparker has voltage, I can't see any sign of current. ratiomatic is up to .06 now, it should go. Bz is negative early, then too positive. Br is a tiny bit negative, just like yesterday. next shot: raise gas to 27msec, try to get something!
Sep 26 2000 10:03:40:857AM	1000926004	Steve Wolfe	Shot#4: icef4 still at -1270, raise gas to 27msec, try to get something! Still nothing. Go to ECDC for awhile. next shot: ef4 to -1280, Br0 from .0015 ->.002, pg4 back to 20msec
Sep 26 2000 10:13:39:030AM	1000926005	Steve Wolfe	Shot#5: 15minutes of ECDC before this shot, ef4 to -1280, Br0 from .0015 ->.002, pg4 back to 20msec another dud. next shot: 14msec on pre-puff.
Sep 26 2000 10:42:54:607AM	1000926006	Steve Wolfe	Shot#6: 14msec on pre-puff; Earl found he needed lower pressure? After 15min ECDC, wait for ITG to drop to 2.5e-6 (gage) another dud. Pressure was down to .043mTorr. next shot: go the other way, pg4 to 30msec, ef4=-1300
Sep 26 2000 11:08:07:920AM	1000926007	Steve Wolfe	Shot#7: go the other way, pg4 to 30msec, ef4=-1300 DUD. pressure read .082. Nothing helps. Maybe the sparker really is disconnected. next shot: raise sparker voltage setting from 650 to 800; should go to 25kV
Sep 26 2000 11:18:26:217AM	1000926008	Steve Wolfe	Shot#8: raise sparker voltage setting from 650 to 800; should go to 25kV Well, there is definitely sparker current on that one. Goes over 1ma before the shot. drop the fill back to 20msec, lower Br0 to .001
Sep 26 2000 11:37:10:420AM	1000926009	Steve Wolfe	Shot#9: drop the fill back to 20msec, lower Br0 to .001 and again a dud. Br is now starting at -1mT, move it back to -.5 RGA looks ok, some 30,31,32 probably boron compounds; nothing rises in the puff but 2 and 4.
Sep 26 2000 11:52:07:903AM	1000926010	Steve Wolfe	Shot#10: Br back to .0015 no help pump out b-top and refill it.
Sep 26 2000 12:11:00:373PM	1000926011	Steve Wolfe	Shot#11:pump out b-top and refill it. dud
Sep 26 2000 12:45:02:623PM	1000926012	Steve Wolfe	Shot#12:Another 15minutes ECDC, using B-top close VUV gate valve plasma disrupted early, big injection at .32 disrupts at .35sec! Who knows! next shot: swing RCUR out a little faster in seg 2. No changes in seg1
Sep 26 2000 01:05:46:217PM	1000926013	Steve Wolfe	Shot#13: swing RCUR out a little faster in seg 2. No changes in seg1 plasma, disrupts in rampdown at 1.75sec two little H-modes. H/D is around 0.1 until rf comes on, then rises to 0.2 I have no good idea how to account for the previous 11 duds. Two silly ideas: 1) we burned something out with the last round of ECDC 2) there was some kind of contaminated gas in the B-top fill line and we purged it through by using it for ECDC next shot: reenable VUV gate valve. hold clearin constant in rampdown
Sep 26 2000 01:22:19:467PM	1000926014	Steve Wolfe	Shot#14: reenable VUV gate valve. hold clearin constant in rampdown plasma, same length. 1MW from E, .5MW ramp from J3. D and J4 fault out. H/D .12 rising to .18 next shot: try leaving ZXL down in rampdown.
Sep 26 2000 01:43:19:340PM	1000926015	Steve Wolfe	Shot#15: try leaving ZXL down in rampdown. disrupted at 1.08sec, injections begin at .94 next shot: repeat
Sep 26 2000 02:13:17:827PM	1000926016	Steve Wolfe	Shot#16: try leaving ZXL down in rampdown. repeat. plasma, 1.75sec; rampdown is no better, no worse both J3 and J4, and E. H/D~.12-.18 next shot: reduce sparker voltage to 700.
Sep 26 2000 02:36:21:280PM	1000926017	Steve Wolfe	Shot#17: reduce sparker voltage to 700, should give 21.5kV. also, try ramping IC_ef4 negative in rampdown plasma, same length. up to 2.5MW but faulting. sparker up to 500uA, still shows gas puff. L-mode at 2.5MW D+E; J3 runs earlier tpo .6MW. H/D up to .22 during D&E pulse next shot: no changes
Sep 26 2000 03:00:09:607PM	1000926018	Steve Wolfe	Shot#18: no changes plasma to 1.75sec J3 and 4 together for awhile, then just j4; then D&E up to 2.25MW Hardly any heating; H/D up to .25 during D&E pulse. next shot: leave RXL nearly constant in rampdown
Sep 26 2000 03:22:14:060PM	1000926019	Steve Wolfe	Shot#19: leave RXL nearly constant in rampdown plasma, same length. Survived a big injection at .8sec, during J-pulse. next shot: hold ZXU up in rampdown (has been moving in).
Sep 26 2000 03:44:14:840PM	1000926020	Steve Wolfe	Shot#20: hold ZXU up in rampdown (has been moving in). plasma, lasted a little longer 1.80sec; EF1U goes to the rail. both j antennas fault out at ~.82sec, D&E on together 2+MW; E faults some. next shot: repeat
Sep 26 2000 04:04:08:450PM	1000926021	Steve Wolfe	Shot#21: repeat plasma to 1.8sec next shot: repeat
Sep 26 2000 04:33:56:310PM	1000926022	Steve Wolfe	Shot#22: repeat plasma, 1.75sec j4 didn't fire; others ok at 0.5MW each. next shot: try ramping the current down by 1.75
Sep 26 2000 06:05:51:420PM	1000926023	Steve Wolfe	Shot#23: try ramping the current down by 1.75 No J-port this shot; j4 isn't coming on. Just try raising power on D&E plasma, to 1.7sec, still about 280kA. J3 ran, J4 didn't. D&E combined for 2MW, clean

Engineering Operator Comments
Shot	Time	Type	Status	Comment
1	09:00:17:873AM	Plasma	Ok
2	09:14:18:403AM	Plasma	Ok
3	09:27:28:780AM	Plasma	Ok
4	09:40:48:310AM	Plasma	Ok
5	10:06:06:890AM	Plasma	Ok
6	10:38:25:810AM	Plasma	Ok
7	10:54:37:623AM	Plasma	Ok
8	11:12:04:327AM	Plasma	Ok
9	11:27:11:373AM	Plasma	Ok
10	11:43:20:967AM	Plasma	Ok
11	12:02:33:217PM	Plasma	Ok
12	12:33:22:920PM	Plasma	Ok
13	12:46:51:140PM	Plasma	Ok
14	01:12:48:733PM	Plasma	Ok
15	01:36:27:733PM	Plasma	Ok
16	01:59:57:840PM	Plasma	Ok
17	02:24:29:280PM	Plasma	Ok
18	02:48:28:340PM	Plasma	Ok
19	03:13:02:467PM	Plasma	Ok
20	03:36:38:810PM	Plasma	Ok
21	04:02:13:780PM	Plasma	Ok
22	04:26:09:200PM	Plasma	Ok
23	04:51:03:327PM	Plasma	Ok