Miniproposals

Miniproposal: 161 Date Filed: 7/18/1996 Title: JET/C-Mod Dimensionless Identity Experiments First Author: Ian Hutchinson Session Leader: Ian Hutchinson (shots 1-38)

Engineering Operator Run Comment

mp161/marmer/hutch/silva

Session Leader Plans

Physics Operators Plans

Session Leader Summaries

Entered: Jul 7 2004 03:49:16:367PM

Author: To Be Determined

Run Summary 960904 JET Dimensionless Similarity MP 161 SL Hutch PO Marmar EO Silva Abstract ________ Plenty of engineering problems. Plasma shape development completed. JET comparison not completed because of RF problems. 1.5MA shot run. Summary _______ Plasmas were obtained fairly reliably with nl04 programmed to 1.6e20 for the first part of the run. The moly bricks were something of a problem. But basically 1.2 MA shots looked fine. (Shot 8 on) H-modes were not easily obtained, even with power substantially above the 0.022nBS level. Only brief H-modes were obtained (e.g. shot14) and only with both transmitters. RF trips were generally observed when H-modes were obtained. Shot 14 and shot 22 on had an OH1 engineering problem that caused a type2 fault and the supply ramps down, crunching the plasma on the inner wall The shots that died this way might be unusual disruption studies. This fault was a cause of considerable difficulty. The problem was eventually isolated during test shots 30-32 by jumpering out a suspect circuit. In the meantime, ICRF transmitter 1 lost its breaker around shot 23. Then we were limited to less than about 1.7MW, which prevented completion of the planned JET comparison. Shot 35 represents the end-point of the equilibrium development for the nearly-double-null JET case. If we can couple >3MW of RF inot this the first JET case will be done. As a final fling. Shot 38 was a 1.5MA shot. It reached flat top an a safety factor of 2.7, but disupted at .78s without much notice. Halo currents were not excessive. There seems to be quite a lot of data that confirms that the edge temperature was low, and hence confirms the Hubbard edge temperature threshold for H-mode. Details _______ Boronized overnight. 30 min of D2 ECDC Late Start because of alternator and PS problems. Start with Shot 960830043: 1MA highish density. 2 Pla First plasma looks fine. RF 2MW dropping to 1MW. Weak H-mode Prad peaks at 2MW and 2pi at 1MW same shape. W=134kJ. Lower clearin by 4mm , Rcur by 2mm, Move RXL out 1cm. Zcur up 1cm. 3 Fiz 4 Dud 5 Dud 6 Pla Disrupts at .69s. Mo injection at .55s. Interferometer gate valve closed. Hit by a brick. Lower triangularity .48. Increase Rxl by 1cm. 7 Pla Ramped down nicely. RF tripped back to 1.2MW. Got delta_l=.40 mkap, but efit says .44. Raise plasma current to 1.2MA. Get RXL out sooner. 8 Pla No H-mode. Great 1.2MA shot. Rf=2MW both transmitters stayed on. Ask for another 5mm on RXL. 9 Pla L-mode. 2MW RF. delta_l=.415 efit and mkap agree. q=3.12 Main chamber pressure gets to 1m torr. Ask for 5mm more on RXL. Raise EF4 PLC limit to 9kA. 10 Pla L-mode. Lower triang. mkap .36, efit .4. RF 2.2MW. Ask for zcur, zxl up by 5mm. lower nl04 to 1.3 from 1.6. 11 Pla Brick at .43s. Disrupts at .465s Early to be caused by shape changes? Maybe not. 12 Pla Disrupts at the same time. Try to avoid the outboard excursion at .4s. 13 Dud 14 Pla Disrupts at 1.2s. (1.1MA) Brief H-mode. RF trips. Mo injections. Caused by OH1 rapidly ramping its current down at 1.166s. This is not commanded by the hybrid. 15 Fiz 16 Pla Disrupts at .8245s. 17 Fiz Raise density back up. RXU decrease by 1cm. 18 Pla Disrupts at .78s. Halo strike 200kA. Lower RF position feedback. Move RXU in another 1 cm. Raise density. 19 Fiz 20 Pla L-mode. RF= 1.5MW, one transmitter. Ramp down. q=3.14 Decrease ZXu by 5mm. 21 Fiz 22 Pla L-mode. RF= 2.3MW. Decrease ZXU a further 5mm. Lower nl04 demand later on to 1.2. 23 Pla Disrupts at .55s. Same OH1 problem as before. Raise Rcur offset in segment 1 to 8000 from 7500. 24 Dud Put Rcur back to 7500. 25 Pla Disrupts at .79s. Same OH1 problem. RF 1.5MW.One transmitter is broken. Jump out the external type2 fault on OH1. 26 Fiz 27 Pla Disrupts at .837s. Same OH1 problem. 28 Fiz 29 Pla Disrupts at .45s. Same OH1 problem. 30 Pstest. OH1 alone. Got the type 2 fault. 31 Pstest. Overtemperature calculation jumped out. OH1 does not fault. 32 Pstest. Repeat. Same result. No fault. 33 Pla Reload of 22. L-mode. Ramped down. Decrease ZXU 5mm, nl04 to 1.2. 34 Fiz 35 Pla Disrupts at 1.35s. L-mode. RF 1.7MW. This is the JET similarity equilibrium. However, we do not have enough power for the full case because only one transmitter. Decrease RXL to 1cm from 3cm. 36 Pla L-mode. Got the higher triangularity. Try for 1.5MA. 37 Fiz Breakdown at 20ms. 38 Pla Disrupts at .76s. At 1.5MA. Went up.

Physics Operator Summaries

Entered: Jul 7 2004 04:36:56:740PM

Author: To Be Determined

Physop summary for 960904 ====================== MP 161 JET Similarity SL: Hutchinson PO: Marmar EO: Silva/Daigle Engineering setup ------------------- Boronize overnight then ECDC (~1 hour in Helium followed by ~1 hour in Deuterium) Power systems setup as for 960830030 Gas setup = standard A-side 20psi D2 B-top 5psi D2 B-side Lower 4psi Ar Enable all for first shot (hybrid) Run plan -------- Start from PCS as on 960830043, a 1 MA 5.3 T shot. After operation is established, work on plasma shape to match the JET equilibrium of interest and raise the current to 1.2 MA. Assuming RF power is sufficient and desired shape is achieved, proceed with the miniproposal for non-dimensional comparison with JET. Hybrid coldstart. File not found errors. Tom Fredian says it is due to running the coldstart procedure at the same time as Josh's new CAMAC test procedure was being run. After Tom fiddled, I reran the hybrid coldstart; all matrices responded. Delay in run start due to 13.8 breaker trip, causing alternator to slow. Several engineering problems, but we managed to get the shape for the JET comparison (shot 35); RF power was too low to run the comparison of interest. 38 was a 1.5 MA, 5.4 Tesla shot. An OH1 problem (spurious type 2 faults) caused a number of disruptions, and one of the RF transmitters went out because of a breaker problem. There were quite a few fizzles, especially after disruptions as well as duds. 1. OH and EF1_L test 2. load 960830043; B_R offset to 6 mT from 5.5; twiddle segment 1 PG3 voltage; reduce nl_04 programming during RF; plasma; late breakdown 3. reduce rcur by 2 mm; reduce clearin by 4 mm; RXL out 1 cm; Zcur up 1 cm; fizzle; late breakdown 4.reduce prefill puff by 1 ms; dud 5 prefill to 18 ms; dud; EF4 imbalance 6. prefill to 18.5 ms; wait for EF4's to cool; plasma; early disrupt; something fell in; TCI gate-valve closed 7. RXL out by 1 more cm; plasma; 8. rxl out sooner; 1.2 MA; plasma; no H-mode 9. rxl out 5 mm more; plasma; 2 MW RF; no H-Mode 10. rxl out 5 mm more; plasma; 11. zcur up 5 mm; zxl up 4 mm; nl_04 down to 1.3e20 from 1.6e20; plasma; late breakdown; early disrupt; brick 12. prefill to 19 ms; plasma; disrupt at about the same time 13. tweak rcur around .3 tp .6 s to open up the outer gap a bit; dud 14. prepuff to 20 ms; plasma; disrupt at start of rampdown; OH1 power supply problem 15. fizzle 16. plasma; disrupt at .81; fair amount of moly; halo warning 17. more gas in segment 1 (between 50 and 100 ms); fizzle 18. nl_04 up to 1.6e20; RXU in by 1 cm; plasma; disrupt; >200 kA halo 19. RXU in one cm; RF feedback on RCUR reduced to -1600 (from -1750); fizzle 20. prefill puff to 19 ms; B_R offset to 5.5 mT; plasma; nice rampdown; no H-mode; 1.5 MW RF 21. ZXU down by 5 mm; gas valve voltage program increased after 0.8 s; fizzle 22. prefill puff to 18 ms; B_R offset to 6 mT; plasma; good rampdown; no H-mode 23. lower nl_04 demand to 1.2e20; ZXU down 5 mm; plasma; disrupt at .57 s; OH1 not following its demand. 24. RCUR offset in seg 1 to 8000; dud 25. RCUR offset in seg 1 to 7500; plasma; disrupt at .79 s; same OH1 power supply problem; only one RF transmitter operational 26. jump out OH1 type 2 fault input; fizzle 27. reduce prepuff to 17 ms; plasma; disrupt at .84 s; same OH1 problem 28. Joe says he found a loose relay; retry; fizzle 29. retry; plasma; disrupt; same problem 30. OH1 test using hybrid programming; failure showed up. 31. OH1 test; no fault 32. OH1 test; no fault 33. reload 22, try for plasma; plasma; good rampdown; big moly injection 34. ZXU down 5 mm; nl_04 to 1.2e20; fizzle 35. prepuff to 18 ms; plasma; disrupt in rampdown 36. RXL in by 2 cm; plasma; better rampdown; 37. fizzle; very late breakdown; try for 1.5 MA 38. B_R offset to 5.5 mT; plasma; 1.5 MA and then disrupt; q_95 down to 2.73 9 fizzles, 4 tests, 4 duds, 21 plasmas.

Session Leader Comments

Physics Operator Comments
Sep 4 1996 10:40:46:410AM	960904003	Earl Marmar	reduce prefill puff by 1 msec; dud
Sep 4 1996 10:40:55:570AM	960904004	Earl Marmar	reduce prefill puff by 1 msec; dud
Sep 4 1996 11:06:05:630AM	960904005	Earl Marmar	prefill to 18 ms; dud; EF4 imbalance
Sep 4 1996 11:27:58:910AM	960904006	Earl Marmar	prefill to 18.5 ms; wait for EF4's to cool; plasma; early disrupt; something fell in; TCI gate-valve closed
Sep 4 1996 11:38:50:970AM	960904007	Earl Marmar	RXL out by 1 more cm; plasma
Sep 4 1996 11:51:21:770AM	960904008	Earl Marmar	rxl out sooner; 1.2 MA; plasma; no H-mode
Sep 4 1996 12:17:16:040PM	960904009	Earl Marmar	rxl out 5 mm more; plasma; 2 MW RF; no H-Mode
Sep 4 1996 12:17:29:290PM	960904010	Earl Marmar	rxl out 5 mm more; plasma;
Sep 4 1996 12:26:42:160PM	960904011	Earl Marmar	zcur up 5 mm; zxl up 4 mm; nl_04 down to 1.3e20 from 1.6e20; plasma; late breakdown; early disrupt
Sep 4 1996 12:49:06:530PM	960904012	Earl Marmar	prefill to 19 ms; plasma; disrupt at about the same time
Sep 4 1996 12:49:20:130PM	960904013	Earl Marmar	tweak rcur around .3 tp .6 s to open up the outer gap a bit; dud
Sep 4 1996 01:49:51:320PM	960904014	Earl Marmar	prepuff to 19 ms; plasma; disrupt at start of rampdown; OH1 power supply problem
Sep 4 1996 01:50:10:010PM	960904015	Earl Marmar	fizzle
Sep 4 1996 01:50:31:880PM	960904016	Earl Marmar	plasma; disrupt at .81; fair amount of moly; halo warning
Sep 4 1996 01:50:49:730PM	960904017	Earl Marmar	more gas in segment 1 (between 50 and 100 ms); fizzle
Sep 4 1996 02:09:54:410PM	960904018	Earl Marmar	nl_04 up to 1.6e20; RXU in by 1 cm; disrupt; >200 kA halo
Sep 4 1996 02:58:49:340PM	960904019	Earl Marmar	RXU in one cm; RF feedback on RCUR reduced to -1600 (from -1750); fizzle
Sep 4 1996 02:59:02:560PM	960904020	Earl Marmar	prefill puff to 19 ms; B_R offset to 5.5 mT; plasma; nice rampdown; no H-mode; 1.5 MW RF
Sep 4 1996 02:59:14:250PM	960904021	Earl Marmar	ZXU down by 5 mm; gas valve voltage program increased after 0.8 s; fizzle
Sep 4 1996 02:59:31:670PM	960904022	Earl Marmar	prefill puff to 18 ms; B_R offset to 6 mT; plasma; good rampdown; no H-mode
Sep 4 1996 02:59:46:030PM	960904023	Earl Marmar	lower nl_04 demand to 1.2e20; ZXU down 5 mm; disrupt at .57 s; OH1 not following its demand.
Sep 4 1996 03:35:26:260PM	960904024	Earl Marmar	RCUR offset in seg 1 to 8000; dud
Sep 4 1996 03:35:58:750PM	960904025	Earl Marmar	RCUR offset in seg 1 to 7500; plasma; disrupt at .79 s; same OH1 power supply problem; appears to be due to an external type 2 fault indication
Sep 4 1996 03:39:05:070PM	960904026	Earl Marmar	jump out OH1 type 2 fault input; fizzle
Sep 4 1996 03:52:16:780PM	960904027	Earl Marmar	reduce prepuff to 17 ms; disrupt at .84 s; same OH1 problem
Sep 4 1996 03:56:08:640PM	960904028	Earl Marmar	Joe says he found a loose relay; retry; fizzle
Sep 4 1996 05:50:06:180PM	960904033	Earl Marmar	reload 22, try for plasma; plasma; good rampdown; big moly injection
Sep 4 1996 05:50:18:150PM	960904034	Earl Marmar	ZXU down 5 mm; nl_04 to 1.2e20; fizzle
Sep 4 1996 05:50:28:280PM	960904035	Earl Marmar	prepuff to 18 ms; plasma; disrupt in rampdown
Sep 4 1996 05:51:38:760PM	960904036	Earl Marmar	RXL in by 2 cm; plasma; better rampdown; fizzle; very late breakdown, try for 1.5 MA
Sep 4 1996 06:21:16:900PM	960904037	Earl Marmar	fizzle; very late breakdown; try for 1.5 MA
Sep 4 1996 06:22:12:110PM	960904038	Earl Marmar	B_R offset to 5.5 mT; plasma; 1.5 MA and then disrupt; q_95 down to 2.73

Engineering Operator Comments
Shot	Time	Type	Status	Comment
1	09:58:55:480AM	Test	Ok	oh1,2 and ef1
2	10:14:55:640AM	Plasma	Ok	no faults
3	10:26:30:210AM	Plasma	Ok	no faults
4	10:35:05:740AM	Plasma	Ok	no faults
5	10:45:17:780AM	Plasma	Ok
6	11:05:04:090AM	Plasma	Ok	no faults
7	11:26:12:370AM	Plasma	Ok	no faults
8	11:39:01:250AM	Plasma	Ok	no faults
9	11:51:17:030AM	Plasma	Ok	no faults
10	12:04:05:320PM	Plasma	Ok	no faults
11	12:17:57:220PM	Plasma	Ok	no faults
12	12:27:02:430PM	Plasma	Ok	no faults
13	12:39:12:090PM	Plasma	Ok
14	12:49:54:190PM	Plasma	Ok	breaker pf pulled at end of shot
15	01:18:23:640PM	Plasma	Ok	question on oh1
16	01:31:10:250PM	Plasma	Ok	no faults
17	01:44:02:160PM	Plasma	Ok
18	01:53:22:120PM	Plasma	Ok
19	02:07:39:670PM	Plasma	Ok	no faults
20	02:19:14:120PM	Plasma	Ok
21	02:30:59:550PM	Plasma	Ok
22	02:38:42:240PM	Plasma	Ok
23	02:50:21:640PM	Plasma	Ok
24	03:06:00:570PM	Plasma	Ok
25	03:14:03:230PM	Plasma	Ok
26	03:37:12:710PM	Plasma	Ok
27	03:44:27:260PM	Plasma	Ok
28	03:54:14:200PM	Plasma	Ok
29	04:02:04:960PM	Plasma	Ok
30	04:18:47:080PM	Test	Ok	oh1 test
31	04:45:16:190PM	Test	Ok
32	04:51:07:010PM	Test	Ok
33	04:58:01:750PM	Plasma	Ok
34	05:10:13:090PM	Plasma	Ok
35	05:20:53:830PM	Plasma	Ok
36	05:32:12:760PM	Plasma	Ok
37	05:41:46:220PM	Plasma	Ok
38	05:49:30:780PM	Plasma	Ok