Miniproposals

Miniproposal: 052 Date Filed: 4/12/1994 Title: ICRF Antenna Tuning (P First Author: Yuichi Takase Session Leader: Steve Golovato (shots 1-28)

Engineering Operator Run Comment

icrf tuning

Session Leader Plans

Physics Operators Plans

Session Leader Summaries

Entered: Jul 7 2004 03:49:11:507PM

Author: To Be Determined

run summary - 941209 --------------------- SL: golovato PO: marmar EO: bertolino/daigle goal - run rf into diverted plasmas at high power sub goals - match diverted plasmas to antenna shape, go to highest possible power, lengthen rf pulse. These goals were all achieved. We got to 2MW out of the transmitter and 1.8MW into the plasma. The plasma was moved up 1cm to better match the antenna shape while maintaining the strike points in the divertor. We ran with small inner and outer gaps to keep elongation below 1.6. The small outer gap also kept the loading high (6-11 ohms). We got some short H-modes wiht the power above 1.5MW. The lognest was in shot 22, 37ms. The H-modes were elm-free. Shots 26-28 went into H-mode at rf turn-on and then the transmitter tripped when the loading dropped leading to a mismatch. Our power limit was thetransmitter screen current, not arcing. From shot 20 onward, we programmed 0.5sec rf pulses. We ran 0.4-0.5sec pulses at up to 1.75MW in L-mode. The molydenum increase saturated as it did in the shorter pulses and showed no upward drift with time. Very good heating was observed, delta(Te_ece)= 0.7-0.8keV, delta(Ti_neutrons)=0.9keV, delta(Wp_efit)=30kJ. In general, it can be said that we have re-established our previous rf performance and gone beyond it in rf pulse length and H-mode transitions. We had several engineering problems which cost us some shots. These should be discussed in the physics operators summary along with the details of how the plasma configuration was established and varied. The session leader shot-to-shot summary can be found the logbook under the session_leader topic. The shot summary was: 22 plasmas (3 disrupted early, at about 400-500ms) 2 fizzles 3 duds (2 because of ef1l problem) 1 lost shot (noise on pressure signal delayed shot too long, alternator ramped down)

Physics Operator Summaries

Entered: Jul 7 2004 04:36:52:440PM

Author: To Be Determined

From: PHYSOP::MARMAR Date: 9-DEC-1994 18:20:33 Description: Physics operator's summary: 941209 941209 RF tuning/heating SL: Golovato EO: Bertolino/Silva/Daigle PO: Marmar This was a succesful run, with high power RF coupled into well diverted plasmas. We tuned to a configuration with the plasma only 1.5 cm below the midplane, inner gap of about 1.5 cm, outer gap of about 1 cm. Various H-modes were seen. See Golovato's Session Leader summary for details. We got off to a slow start. The first shot disrupted early and 3 fuses and one SCR were lost from a TF supply. Shot 2 was aborted because of a noise problem on the torus ion guage which appeared during check phase. This recurred for shot 3, where the fill permissive was bypassed, and then never recurred during the run. Shots 12, 18 and 19 were duds; this was almost certainly due to the fact that EF1L was not reaching its programmed current before commutation. This was apparently fixed by tweaking the gate drive angle and the rest of the shots went without problems. shot 1 start from 941208028 with changes to correct RCUR along with adding offset of 10000. Plasma was too far inside, EF2's railed, Kappa=1.77, VDE up at 0.405 s. Fill was 1.3e-5 D2 puff and fill from A_side. 2 abort; ion gauge problem 3 reload 941208027; 1.4e-5; ion gauge noisy during check, went anyway; wierd shot; many OH lurches; hards; funny current rise; disrupt at 1.09s 4 retry after reloading shot again; looks like shot 1; some hards 5 clearin to -.01; zcur down earlier; 1.5e-5; fizzle 6 1.4e-5; retry; good shot; hards better; Elmy H-mode during RF? 7 repeat; good 8 zcur up .005; rxl out .002; zxl up .005; Ar increased slightly; good plasma 9 repeat; good plasma 10 zcur up .005; zxl up .005; add argon; good plasma 11 repeat; good plasma; RF tripped 12 clearin out .005; rcur out .005; rxl out .002; more argon; dud 13 fill 1.5e-5; retry; good plasma 14 tweak ef1's late in segment 1; reduce clearin integral gain and move to start at 0.3 s; fizzle 15 reload 13; 1.4e-5; good plasma 16 up nel request to 1.1e20; good plasma 17 slow Ip rampdown; extend nl prop gain beyond end of shot; good plasma 18 repeat dud 19 fill 1.5e-5; RF assist on; dud; discovered that EF1L had not been reaching demand current at t=0 20 adjusted gate drive angle on EF1L supply; retry; good plasma 21 no changes; good plasma 22 move rcur in after 1 second; good plasma; PF problem late; 400kA disrupt on rampdown 23 repeat; ugly shot; hards burst at disruption 24 reload shot 21; lower nel demand to 0.9e20; good plasma 25 repeat; higher RF power; good plasma; RF tripped 26 nel demand back to 1.1e20; good plasma; short ELM free H-mode during RF; RF tripped 27 move nel feedback earlier (start at 0.1 s); more argon in first puff; good plasma; short RF 28 no changes; good plasma; short RF, ELM-free H-mode. 28 attempts, 2 fizzles, 3 duds (EF1L problem), 1 engineering abort 22 plasmas

Session Leader Comments
Dec 9 1994 08:41:28:810AM		Steve Golovato	Run Goals - run diverted discharges, try to match to antenna shape, bring up power as high as possible. Further things to try are long rf pulses, rf power ramp, several densities.
Dec 9 1994 08:52:19:660AM	941209001	Steve Golovato	941209001 - this shot is set up like shot 941208027 with some tweaking to be like 941208028 without disrupting, as 941208028 did. Got early disruption at about 400ms, like shot 941208028.
Dec 9 1994 10:02:05:710AM	941209002	Steve Golovato	941209002 - Go back to shot 941208027, which was diverted and ran ok. gas gauge problem, aborted before shot taken.
Dec 9 1994 10:13:40:940AM	941209003	Steve Golovato	941209003 - Repeat attempt at shot 941208027, ran but disrupted at 1.1s. rf arced during second pulse, at 1.25MW. plasma ragged. inner and outer gaps 2cm.
Dec 9 1994 10:33:19:370AM	941209004	Steve Golovato	941209004 - lower rf Prf a little, reduce clearin by 5mm to mak less elongated plasma (last shot was 1.67), smaller gaps for better loading. Disrupted at 400ms again. we have control problems to iron out.
Dec 9 1994 10:52:05:300AM	941209005	Steve Golovato	941209005 - fizzle, try again.
Dec 9 1994 11:09:22:280AM	941209006	Steve Golovato	941209006 - good shot. 1.5MW, maybe an h-mode. gaps about 1.5cm, plasma about 2-2.5cm low.
Dec 9 1994 11:21:11:920AM	941209007	Steve Golovato	941209007 - some tuning, re-take same shot. good shot again, loading good, 6 ohms. Prf=1.3 MW match almost perfect at .6s, good for calibrating analysis 0program.
Dec 9 1994 11:44:29:150AM	941209007	Steve Golovato	941209007 - delta(Te_ece) = 800eV, peaked in center.
Dec 9 1994 11:43:15:880AM	941209008	Steve Golovato	941209008 - moving plasma up 5mm, adjusting x-point up and out also to try to keep strike points below noses and elongation not too high. Good shot, plasma higher, better matched to antenna shape, probe at top of antenna glowed for first time today. 1.5MW, good heating.
Dec 9 1994 11:59:13:970AM	941209008	Steve Golovato	941209008- delta(Ti_neut)=900eV.
Dec 9 1994 11:58:37:060AM	941209009	Steve Golovato	941209009- same as last shot, power higher. good shot. 1.75MW, 40kV.
Dec 9 1994 12:24:30:970PM	941209010	Steve Golovato	941209010- raising plasma another 5mm, adjusting x-point as before. another good shot. 1.8MW.
Dec 9 1994 12:29:26:750PM	941209011	Steve Golovato	941209011- good shot. 2MW out of transmitter minus reflected power and line losses gives 1.85MW. transmitter had screen current trip after 50ms.
Dec 9 1994 12:42:09:600PM	941209012	Steve Golovato	941209012- moving plasma out 5mm, increasing inner gap which has been a little less than 1cm, and decreaing outer gap to give more loading. adjusting x-point out may improve inner strike point, which has been getting pretty close to nose. after all this explanantion, we got a dud.
Dec 9 1994 01:05:41:540PM	941209013	Steve Golovato	941209013- good shot. transmitter tripped at 2MW again. Prf=1.8MW, loading up to 7.5 ohms from about 6 ohms with plasma moved out by 5mm. perhaps h-mode at end of rf pulse, continues after rf.
Dec 9 1994 01:11:46:500PM	941209014	Steve Golovato	941209014- tuned to higher loading. fizzled.
Dec 9 1994 01:41:17:460PM	941209015	Steve Golovato	941209015- good shot, power a little lower but tranmitter did not trip. delta(Wp_efit)=30kJ, no rf power, loading data this shot.
Dec 9 1994 01:43:03:250PM	941209015	Steve Golovato	941209015- good shot, power a little lower but tranmitter did not trip. delta(Wp_efit)=30kJ, no rf power, loading data this shot. brief h-mode at 830ms.
Dec 9 1994 01:51:30:050PM	941209016	Steve Golovato	941209016- raise density about 20%. good shot. transmitter tripped again. desnity up by about 10%. 1.8MW, loading up to 11 ohms. need to tune.
Dec 9 1994 02:03:13:930PM	941209016	Steve Golovato	941209016- raise density about 20%. good shot. transmitter tripped again. desnity up by about 10%. 1.8MW, loading up to 11 ohms. need to tune.
Dec 9 1994 02:09:32:740PM	941209017	Steve Golovato	941209017- good shot, 1.8MW, apparent h-mode dithering during rf.
Dec 9 1994 02:18:17:510PM	941209018	Steve Golovato	941209018- lower power, 500ms rf pulse. dud. try again.
Dec 9 1994 02:40:49:400PM	941209019	Steve Golovato	941209019- another dud. apparent ef1l power supply problem.
Dec 9 1994 03:16:55:030PM	941209020	Steve Golovato	941209020- good shot, rf ran for 400ms before transmitter tripped. 1.6MW, loading rose during rf, detuning match.
Dec 9 1994 03:23:41:610PM	941209021	Steve Golovato	941209021- good shot, 1.4MW for 0.5 sec. no obvious impurity accumulation beyond shorter pulse level.
Dec 9 1994 03:45:47:270PM	941209022	Steve Golovato	941209022- raise power back up. tripped near end of pulse. no rf data. h-modes at 530ms and 675ms. about 30ms each, elm-free. power approximately 1.5MW. loading drops from 8 to 4 ohms in h-mode, tuning to intermediate point to try to hold power up, keep h-mode.
Dec 9 1994 03:58:45:140PM	941209023	Steve Golovato	941209023- disrupted early, at 500ms, in trouble from the beginning.
Dec 9 1994 04:40:21:160PM	941209024	Steve Golovato	941209024- good shot, density lowered about 10%.
Dec 9 1994 04:41:17:940PM	941209025	Steve Golovato	941209025- good shot, density lowered about 10%. 1.75MW, l-mode.
Dec 9 1994 04:42:57:660PM	941209026	Steve Golovato	941209026- good shot, density back up. 1.8MW, transmitter tripped. went into h-mode, then rf tripped.
Dec 9 1994 04:55:09:550PM	941209027	Steve Golovato	941209027- lowered power a little. 1.8MW, goes onto h-mode, rf trips immediately.
Dec 9 1994 05:04:30:560PM	941209028	Steve Golovato	941209028- lowered power, moved rf turnon later, try again. same as last shot. goes into h-mode, then transmitter trips.

Physics Operator Comments

Engineering Operator Comments
Shot	Time	Type	Status	Comment
1	08:42:07:000AM	Plasma	Ok	tf comm fault AFTER disruption
2	09:46:32:770AM	Plasma	Bad	fill pressure reading not steady, shot aborted with estop
3	09:58:58:180AM	Plasma	Ok	no faults
4	10:25:19:430AM	Plasma	Ok	no faults
5	10:42:25:820AM	Plasma	Ok	no faults
6	10:54:35:440AM	Plasma	Ok	no faults
7	11:11:25:600AM	Plasma	Ok	no faults
8	11:27:04:360AM	Plasma	Ok	no faults
9	11:47:57:620AM	Plasma	Ok	no faults
10	12:03:24:380PM	Plasma	Ok	no faults
11	12:19:07:400PM	Plasma	Ok	no faults
12	12:34:02:210PM	Plasma	Ok	no faults
13	12:49:30:180PM	Plasma	Ok	No Faults.
14	01:09:35:770PM	Plasma	Ok	no faults fizzle
15	01:23:47:300PM	Plasma	Ok	no faults
16	01:41:40:400PM	Plasma	Ok	no faults
17	01:59:54:600PM	Plasma	Ok	No Faults.
18	02:16:09:160PM	Plasma	Ok	No Faults.
19	02:28:54:770PM	Plasma	Ok	no faults.
20	03:00:14:950PM	Plasma	Ok	No Faults.
21	03:14:35:920PM	Plasma	Ok	No Faults
22	03:28:57:720PM	Plasma	Ok	COM fault OH1 & OH2 L
23	03:45:22:820PM	Plasma	Ok	No Faults.
24	03:59:56:250PM	Plasma	Ok	No faults.
25	04:13:55:600PM	Plasma	Ok	No faults
26	04:28:48:970PM	Plasma	Ok	No faults.
27	04:44:26:450PM	Plasma	Ok	No faults
28	04:57:42:010PM	Plasma	Ok	No faults.