| Miniproposals | ||||||||||
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| Operators | |
| Session leader(s): | Brian Labombard |
| Physics operator(s): | Robert Granetz |
| Engineering operator(s): | Ed Fitzgerald,Sam Pierson,Bill Byford |
| Engineering Operator Run Comment |
| MP#475 Cryopump Startup PO:Granetz SL:Labombard EO:Fitzgerald,Pierson,By |
| Session Leader Plans |
| Entered: May 31 2007 12:52:54:050PM |
| Author: Brian Labombard |
| Run Plan for 1070601 MP#475 ""Cryopump Startup"" Goal Explore cryopump density control in near double-null discharges with SSEP control and variation. Investigate both ohmic L-mode and ICRF heated H-mode discharges. In particular, we will be seeing if the cryopump can be used to lower the H-mode density below its natural, unpumped values. In accomplishing these goals, MP#475 Phases IV and V would be completed. Plan We will begin cooldown of the cryopump at around 8:00AM. First we will perform some simple pumping speed tests, puffing in D2 via the NINJA system and operating with the torus gatevalves closed. We will also do some cross-calibration tests, comparing the amount of gas injected with the amount of gas in the torus, both with the pump warm (no pumping) and after a regeneration cycle. Then we will continue studies of particle removal in near-DN discharges (ohmic L-mode on first half of run, ICRF heated H-modes on second half). Finally, if there is time, we will attempt to produce some strongly-pumped USN H-modes, that is, if the plasma is accommodating. (It was on Brock's recent run, MP#481, 1070530.) Shot Plan (1) No-power shot cycles with gatevalves closed. A - Puff NINJA (30 psi) for 2 seconds with cryopump warm and gatevalves closed B - Puff NINJA again with cryopump cold and regen with gatevalves closed (2) Ohmic discharges - map out effect of SSEP and Ip on pumping. Reload from shot#1070525030, running on segment#4 (near DN, SSEP control). Ip=0.8 MA, Bt=5.4 tesla Program NL04 = 1.0e20 until 0.8 s, then zero after 0.8 s Program SSEP = -3 mm (this results in SSEP = -2 mm) - One shot with pump warm (20 deg K), one shot with pump cold. - SSEP = -6 mm, one shot with pump cold. - SSEP = -9 mm, one shot with pump cold. Repeat above sequence for Ip=0.6, NL04 = 0.75 Repeat above sequence for Ip=1.2, NL04 = 1.5 (3) ICRF-heated H-mode density control in near-DN topology Ip=1.0 MA, Bt=5.4 tesla Program NL04 = 1.25e20 until 0.5 s, then zero after 0.5 s Program SSEP = -3 mm Turn on ICRF power (2MW) from 0.7 to 1.5 seconds - take several shots, varying RF turn-on time to change density at L-H time - try programming a jog to SSEP=0 just after L-H transition - vary starting density, NL04=1.0, 0.8 (4) ICRF-heated H-mode density control in USN topology (plasma willing) Ip=0.8 MA, Bt=5.4 tesla Program NL04 = 1.0e20 up to 0.5 s, then zero after 0.5 s Turn on ICRF power (2.5MW+) from 0.7 to 1.5 seconds - take several shots, varying RF turn-on time to change density at L-H transition |
| Physics Operators Plans |
| Entered: Jun 1 2007 08:40:47:280AM |
| Author: Robert Granetz |
Engineering setup for Friday 01 June 2007
MP#475 Cryopump experiments
Session leaders: B. LaBombard
Physics operator: R. Granetz
ECDC overnight in D2, pressure=2e-4 Torr. Rmin/Rdwell/Rmax = 44/45/103 cm.
Bake at 60 C.
Power systems as on 1070525031.
A-coil configuration: normal [Dtop -Dbot -Jtop +Jbot] and enabled.
Gas Setup:
fill B-Top with 6 psi D2 Hybrid enabled (PG4)
fill B-side lower with 2 psi Kr Hybrid DISABLED (PG1)
leave B-side upper as is Hybrid DISABLED (PG2)
fill B-main (C-side) with 40 psi D2 Hybrid enabled (PG3)
fill NINJA with 30 psi D2 ENABLED
Enable the following gate valves and shutters, assuming no vacuum problems:
ECE, VUV, Z-bolo shutters. Enable DNB gate valve when requested by
DNB operator.
Torvac setup: Gate valves closed during pulse and for 300 seconds after.
Special diagnostics: Fast H-alpha diodes; other fluctuation diagnostics
-------------------------------------------------------------------------------
Cryopump: Start cooldown to LN2 and LHe temperatures at 08:00. Just before
09:00 we will do a few pumping and regeneration cycles.
This will involve running no-power C-Mod shot cycles, puffing D2
into the vessel via the NINJA system and operating with
gatevalves closed. We will be ready to operate the pump with
plasma around 09:00.
ICRF Setup: Transmitters 1 & 2 in RUN-ON by 08:30. 2+ MW needed on some shots
LH Setup: not needed
-------------------------------------------------------------------------------
Run plan:
No-power C-Mod shot cycles will taken prior to 09:00 to perform
cross-calibration checks of gas input and regeneration recovery
inventories.
Setup for first plasma:
Reload from shot#1070525031, running on segment#4 (near DN, SSEP control).
Ip=0.8 MA, Bt=5.4 tesla
Program NL04 = 1.0e20 until 0.8 s, then zero after 0.8 s
Program SSEP = -3 mm (this results in SSEP = -2 mm)
See session leader plan for remaining shots.
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| Session Leader Summaries |
| Entered: Jun 1 2007 11:08:07:470PM |
| Author: Brian Labombard |
| Run Summary for 1070601 MP#475 ""Cryopump Startup"" The cryopump systems performed well today, cooling to LHe temperature on any shot that we desired pumping. Cool-down from room temperature was fast (~20 minutes) and better controlled, resulting in the helium and nitrogen exhaust temperature transients staying almost within the 60 degree C difference spec. The cryopump consumed only about 60 liters of liquid helium during the full day of operation. It is a very efficient cryopumping system. We began the run with some gas inventory calibration shots (1 & 2). Shots 3-19 continued the exploration of density control in near-DN ohmic discharges with varying SSEP and plasma currents. We programmed for a constant density until 0.8 seconds and then shut the piezo valve off, resulting a density-pumpout rampdown of NL04. All near-DN plasmas exhibited a short, fast pump-out transient (a delta of about NL04 ~ 0.2e20) over a 0.15 to 0.2 s time scale. SSEP values closer to 0 favored a larger density pumpout transient. But this was followed by a much slower density pumpout ramp at this lower, 'saturated density' value. This saturation density value was found to depend on plasma current - lower for lower Ip values. There was some control-room speculation about mechanisms that might contribute to this effect including a transition from high to low recycling and a possible influence of the lower, unpumped divertor gas inventory, which is rather high in these near DN plasmas. To examine the latter effect, we ran a USN discharge (shot 20) with the same density/gas programming. In contrast to the near-DN plasmas, it showed a steady pumpout behavior of the plasma density, from NL04 = 1.0 to 0.5 at the end of flattop. In the remainder of the run, we focussed on applying strong cryopumping to ICRF heated H-modes. We ran plasmas with SSEP near -3 mm and hit these with 2MW of RF just as the density started to pump-out. Shot 23 (pump off) and 25 (pump on) showed the typical result. With pump off, the plasma exhibited a single steady EDA H-mode with midplane pressures around 0.35 mtorr and NL04 peaking in time at 2.2e20. With pump on, the plasma exhibited a more ELM-free behavior (3 H-nodes), NL04 peaking at 2e20 and midplane pressures at 0.18 mtorr. Thus it became very clear that the H-mode density was not going to be easy beast to affect with the cryopump. We decided that we needed a bigger hammer. We started programming a jog in SSEP towards strong upper-null right at the L-H transition (shot 29 - no RF, 30 - with RF). The L-mode plasma (29) exhibited good pumpout behavior, but only after the SSEP jog. This suggested that the x-point balance when SSEP=0 may actually favor the LSN direction. (In retrospect, we should have done a simple SSEP scan with the pump off to explore this, looking at the resultant upper/lower divertor neutral pressure balance.) When we got H-modes (shots 30, 32), they were of the short-lived ELM-free variety. RF power was not steady, also contributing to the multiple L-H-Ls. In the hope that we might get an H-mode in USN to apply our biggest pumping hammer, we ran shot 31. The RF ran clean at slightly under 2 MW, but the plasma stayed in L-mode, pumping out rather dramatically. This L-mode was actually a pretty impressive low density plasma (NL04 =0.57e20), with Te > 4.5 kV and decent stored energy. |
| Physics Operator Summaries |
| Entered: Jun 1 2007 05:15:55:223PM |
| Author: Robert Granetz |
Run summary for Friday 01 June 2007
MP 475: Cryopump experiments
Session leader: Brian LaBombard
Physics operator: R. Granetz
The first 2 shots were gas-only cycles to check/calibrate the gas inventory
diagnostics. Then the first half of the day ran near-double-null and
upper-null plasmas without any RF, with and without the cryopump on. We
found that it pumps USN very well. But in DN, the density initially falls,
but then reaches a plateau. The latter part of the day had 2 MW of RF and
H-modes. We were able to obtain H-modes in near-DN, including shots that
scanned SSEP up to +5 mm, so they were weakly USN. No obvious pumping on
these shots, though. We also ran a regular USN shot, which had very good
pumping, but no H-modes despite 2.0 MW of ICRF. The machine ran well, with
only a handful of typical problems.
Scorecard: 23 plasmas
1 dud (power supply problem)
5 fizzles
0 power supply tests
3 no-power MDS shot cycles
--------------
Total: 32 shot cycles
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| Session Leader Comments | |||
| Jun 1 2007 09:27:20:210AM | 1070601001 | Brian Labombard | 1 - No power, gas puff test NINJA puff only: 1354 torr D2, ABLim, trig: 0, duration: 2.0 99 torr-l injected by NINJA, 45 torr-l/s 4060*E-top indicates 101 torr-l in vessel with gate valves closed. Next: repeat with pump cold |
| Jun 1 2007 09:38:33:403AM | 1070601002 | Brian Labombard | 2 - No power, gas puff test, cryopump cold NINJA puff only: 1321 torr D2, ABLim, trig: 0, duration: 2.0 95 torr-l injected by NINJA 4060*E-top (slow) indicates 102 torr-l in vessel after regen with gate valves closed. Next: go for near DN plasma, pump warm |
| Jun 1 2007 09:46:18:217AM | 1070601003 | Brian Labombard | 3 - Ip=0.8, Bt=5.45, SSEP=-1 mm, NL04=1.2 to 1.8e20 cryopump warm oops - NINJA puff was on Next: Repeat with NINJA off, pump warm |
| Jun 1 2007 10:22:28:337AM | 1070601004 | Brian Labombard | 4 - Ip=0.8, Bt=5.45, SSEP=-2 mm and rising, NL04=1.1 cryopump warm 32 mtorr on F-top, 36 mtorr on B-bottom 51 torr-l injected Next: Repeat with pump cold |
| Jun 1 2007 10:41:06:963AM | 1070601005 | Brian Labombard | 5 - Ip=0.8, Bt=5.45, SSEP=-2 mm and rising NL04=1.0 with prompt drop to 0.75 in .2 s cryopump cold Next: Repeat with pump cold, ssep = -6 |
| Jun 1 2007 10:48:47:353AM | 1070601006 | Brian Labombard | 6 - Ip=0.8, Bt=5.45, SSEP=-6 mm NL04=1.0, prompt drop to 0.8 in .2 s cryopump cold peak pumping about 93 torr-l/s Next: Repeat with pump cold, ssep = -9 |
| Jun 1 2007 11:00:17:090AM | 1070601007 | Brian Labombard | 7 - Ip=0.8, Bt=5.45, SSEP=-9 mm, outer gap shrinking from 1.4 to .6 cm NL04=1.0 slow drop to 0.8 in by 1.5s cryopump cold peak pumping about 82 torr-l/s peak cryopump pressure is 1.5 mtorr Next: Repeat with pump cold, ssep = -9, flat gap programming |
| Jun 1 2007 11:15:22:550AM | 1070601008 | Brian Labombard | 8 - Ip=0.8, Bt=5.45, SSEP=-9 mm, outer gap at 14mm NL04=1.0 drops faster to 0.78 by 1.3s cryopump cold peak pumping about 84 torr-l/s peak cryopump pressure is 1.5 mtorr Next: Repeat with pump cold, ssep = -9, gap increased to 2 cm. |
| Jun 1 2007 11:35:01:283AM | 1070601009 | Brian Labombard | 9 - Ip=0.8, Bt=5.45, SSEP=-9 mm, outer gap at 20 mm NL04=1.0 drops at about same rate at shot 8 gas valve comes on full at 1.25s - feedback problem cryopump cold peak cryopump pressure before 1s is 1.8 mtorr Next: Repeat with pump cold, ssep = -3, outer gap at 2 cm. |
| Jun 1 2007 11:57:48:420AM | 1070601010 | Brian Labombard | 10 - Ip=0.8, Bt=5.45, SSEP=-3 mm, outer gap at 20 mm NL04=1.0 promptly drops to 0.8 in 0.12s, then slowly pumps out after. cryopump cold peak cryopump pressure is 4 mtorr Next: Go to pump cold, ssep = -3, Ip=0.6, gap=15mm, NL04=0.75 |
| Jun 1 2007 11:57:34:230AM | 1070601011 | Brian Labombard | 11 - Ip=0.6, Bt=5.45, SSEP=-3 mm, outer gap at 13 mm NL04=0.8 promptly drops to 0.63 in 0.15s, then slowly pumps out after. cryopump cold 54 torr-l/s peak pumping peak cryopump pressure is 1.8 mtorr Next: Go to pump cold, ssep = -6 |
| Jun 1 2007 12:47:49:183PM | 1070601013 | Brian Labombard | 13 - Ip=1.15, Bt=5.45, SSEP=-6 mm, outer gap at 15 mm until things go sour at 0.66 s disrupts at 1.1 s peak NL04=1.5 starts prompt pumpout cryopump cold ~140 torr-l/s peak pumping peak cryopump pressure is 3.7 mtorr Next: Repeat |
| Jun 1 2007 12:55:37:080PM | 1070601015 | Brian Labombard | 15 - Ip=1.15, Bt=5.45, SSEP=-6 mm, outer gap at 15 mm and increasing until things go sour disrupts at 0.97 s peak NL04=1.4, starts prompt pumpout cryopump cold ~134 torr-l/s peak pumping peak cryopump pressure is 4.7 mtorr Next: go to 1MA, NL04 =1.2, SSEP =- 3 mm |
| Jun 1 2007 01:37:33:170PM | 1070601018 | Brian Labombard | 18 - Ip=1.0, Bt=5.45, SSEP=-5 mm, outer gap at 15 mm and increasing until things go sour disrupts at 0.97 s peak NL04=1.2, prompt pumpout to 0.9 in 0.18 s Density has trouble dropping below NL04=0.85 cryopump cold ~112 torr-l/s peak pumping peak cryopump pressure is 12 mtorr Next: go to 1MA, NL04 =1.2, SSEP =- 3 mm |
| Jun 1 2007 02:34:11:180PM | 1070601019 | Brian Labombard | 19 - Ip=1.0, Bt=5.45, SSEP = -2 mm Gas valve off at 0.8 s NL04=1.15, prompt drop to 0.93 then holds around 0.87 peak cryopump pressure is 5 mtorr 122 torr-l/s pumping |
| Jun 1 2007 02:11:37:497PM | 1070601020 | Brian Labombard | 20 - Ip=1.0, Bt=5.45, USN, outer gap at 13 mm peak NL04=1.0, great pumpout to 0.5 by 1.5 s piezo valve full on up to 0.8 s cryopump cold ~103 torr-l/s peak pumping peak cryopump pressure is 5.5 mtorr Next: Repeat shot#19, gas off at 0.5s, RF on at 0.7s |
| Jun 1 2007 02:22:01:027PM | 1070601021 | Brian Labombard | 21 - Ip=1.0, Bt=5.45, SSEP = -3 mm Gas valve off at 0.5 s NL04=1.1 at 0.5s, down to 0.8 at rf turn-on (0.7 s) 3 H-modes piezo valve is full on up to 0.5 s peak cryopump pressure is 9 mtorr Next: Repeat with pump warm, NL04 = 0.9 flat program |
| Jun 1 2007 03:00:09:110PM | 1070601023 | Brian Labombard | 23 - Ip=1.0, Bt=5.45, SSEP = -3 mm pump warm, flat NL04 program at 0.9 RF at 2 MW, EDA H-mode 8 mtorr in cryopump (pump is off) Next: Repeat with pump cold, NL04 = 0.9, turn off gas at 0.6 s. |
| Jun 1 2007 03:28:10:547PM | 1070601025 | Brian Labombard | 25 - Ip=1.0, Bt=5.45, SSEP = -3 mm pump cold, flat NL04= 0.9, gas turn off at 0.6 s RF at 2 MW, 3 H-modes, ELM-free like disrupts at 1.25 s 1.6 mtorr in cryopump Next: Repeat with pump cold, NL04 = 0.9, turn off gas at 0.6 s, jog SSEP to +5 mm at 0.7 s |
| Jun 1 2007 04:42:39:173PM | 1070601029 | Brian Labombard | 29 - Ip=1.0, Bt=5.45, SSEP = -3 mm pump cold, flat NL04= 0.9 then gas turn off at 0.6 s, SSEP jog to +5 mm at 0.7 s No RF Good pumpout: 0.9 pumping down to 0.54 at 1.5 s Next: Repeat with RF on and SSEP jog to +10 mm |
| Jun 1 2007 05:04:44:347PM | 1070601030 | Brian Labombard | 30 - Ip=1.0, Bt=5.45, SSEP = -3 mm, SSEP jog to +5 mm at 0.7 s, dropping down to +2 mm pump cold, flat NL04= 0.9 then gas turn off at 0.6 s RF at 2 MW dropping to 1MW Multiple H-modes Next: go to USN |
| Jun 1 2007 05:07:09:410PM | 1070601031 | Brian Labombard | 31 - Ip=1.0, Bt=5.45, USN pump cold, flat NL04= 0.9 then gas turn off at 0.6 s RF steady at 2 MW, no H-modes Good pumpout - NL04 = 0.9 to 0.57 Next: go back to near-DN, SSEP = 0 jogging to SSEP=+5 mm |
| Jun 1 2007 05:22:20:973PM | 1070601032 | Brian Labombard | 32 - Ip=1.0, Bt=5.45, SSEP = -1, jogging to +3 or so at 0.7 s pump cold, flat NL04= 0.9 then gas turn off at 0.6 s RF at 2 MW dropping to 1 MW, multiple H-modes |
| Jun 1 2007 05:36:45:520PM | 1070601032 | Brian Labombard | According to the helium flow meter, we used 60 liters of liguid helium to run the cryopump today. |
| Physics Operator Comments | |||
| Jun 1 2007 08:45:20:880AM | Robert Granetz | Loaded shot 1070525031, with seg 4 active (near DN, SSEP control). Imported seg 1 from 1070531027 (last startup from yesterday). Confirmed Ip=0.8 MA, Bt=5.4 T. Programmed nl_04 to be 1.0e20 until t=0.8 s, then 0.0 after that. Programmed SSEP to be -3 mm (this results in SSEP = -2 mm). | |
| Jun 1 2007 08:52:58:153AM | 1070601001 | Robert Granetz | Shot 01 -- This will be a no-power shot with just NINJA puffing; no piezo valves. Brian wants to calibrate the inventory measurements. |
| Jun 1 2007 09:19:40:783AM | 1070601001 | Robert Granetz | Shot 01 -- no-power gas inventory test with cryopump warm. Injected 3.2e21 molecules and observed 3.2e21 molecules in vessel. Good agreement. Next shot: Cool down the cryopump and do this no-power gas inventory shot again. Note: torus gate valves closed for 300 seconds during/after shot. |
| Jun 1 2007 09:36:36:647AM | 1070601002 | Robert Granetz | Shot 02 -- No-power gas inventory test, using just NINJA, and with the cryopump cold. Next shot: go for plasma. |
| Jun 1 2007 09:45:54:637AM | 1070601003 | Robert Granetz | Shot 03 -- Plasma. Good shot. NINJA was mistakenly left on, with 3e21 molecules injected. This resulted in a density rampup, and then a disruption late in the shot. Cryopump was warm. Next shot: repeat, but without the NINJA puff. |
| Jun 1 2007 10:17:27:757AM | 1070601004 | Robert Granetz | Shot 04 -- Plasma. Good shot. Cryopump warm. Nearly DN (LSN-dominated). Next shot: same, but with cryopump on. |
| Jun 1 2007 10:26:20:043AM | 1070601005 | Robert Granetz | Shot 05 -- Plasma. Good shot. Cryopump cold. Still ohmic. Next shot: change SSEP to -6 mm (was -3 mm). Cryopump cold. |
| Jun 1 2007 10:46:51:167AM | 1070601006 | Robert Granetz | Shot 06 -- Plasma. Good shot. Cryopump cold. SSEP=-6 mm. Next shot: Change SSEP to -9 mm. Program RCUR to ramp out slightly to keep the outer gap more constant. Turn on DPCS_FTAE2 (at request of J. Sears) |
| Jun 1 2007 11:12:15:940AM | 1070601007 | Robert Granetz | Shot 07 -- Plasma. Good shot. I screwed up the direction of RCUR change, thus making the outer gap vary even more. Cryopump cold. Krypton was puffed. The pre-fill pressure is extremely low (.015 mTorr) because of the cryopump, but the breakdown and startup is just fine...no need to change the pre-fill puff. Next shot: program RCUR the other way (decrease RCUR --> increase outer gap). Increase pre-fill puff by 5 ms. Turn off krypton. |
| Jun 1 2007 11:16:05:630AM | 1070601008 | Robert Granetz | Shot 08 -- Plasma. Good shot. The outer gap is now constant at 14 mm. This does indeed increase the density pumpout speed. No krypton puff. Next shot: increase outer gap to 20 mm (decrease RCUR by 3 mm). Increase pre-fill puff by another 5 ms. Keep SSEP at -9 mm. Turn krypton back on. |
| Jun 1 2007 11:33:16:020AM | 1070601009 | Robert Granetz | Shot 09 -- Plasma. Good shot. Density feedback misbehaved, resulting in unwanted gas fueling. Next shot: repeat. Zero the pre-programmed density valve voltage. Change SSEP to -3 mm. |
| Jun 1 2007 11:43:37:683AM | 1070601010 | Robert Granetz | Shot 10 -- Plasma. Disrupted at t=1.54 s. EFC is hitting its rails, but N/Ncrit is below unity. Next shot: decrease outer gap to 15 mm (increase RCUR by 2.5 mm). Set Ip to 0.6 MA. Set nl_04=0.75e20 m-2. |
| Jun 1 2007 11:58:46:060AM | 1070601011 | Robert Granetz | Shot 11 -- Plasma. Disrupted at t=1.44 s. Not a vertical stability problem. Next shot: change SSEP to -6 mm. Tweak RCUR to make the outer gap more constant. |
| Jun 1 2007 12:13:23:347PM | 1070601012 | Robert Granetz | Shot 12 -- Plasma. Good shot. Next shot: Raise Ip to 1.2 MA. Raise nl_04 to 1.5e20 m-2. |
| Jun 1 2007 12:29:46:880PM | 1070601013 | Robert Granetz | Shot 13 -- Plasma. Briefly made it to 1.2 MA, but current starts to droop after t=0.8 s, and then eventually disrupts. Next shot: Reprogram IC_EF4 to 2 kA for most of shot. Raise PLC limit on EF3 to 13 kA (from 12 kA). Slow down the current ramp slightly. |
| Jun 1 2007 12:38:14:710PM | 1070601014 | Robert Granetz | Shot 14 -- Fizzle. Post-disruption recovery. Next shot: try again; no DPCS changes |
| Jun 1 2007 12:54:57:330PM | 1070601015 | Robert Granetz | Shot 15 -- Plasma. Disrupted at t=0.97, with Ip=1.2 MA. Looks like it had vertical stability problems. I_halo_lower = 300 kA. Next shot: reduce Ip to 1.0 MA and nl_04 to 1.2e20 m-2. But it will be a fizzle anyway. |
| Jun 1 2007 01:06:29:503PM | 1070601016 | Robert Granetz | Shot 16 -- Fizzle. Post-disruption recovery. Next shot: no changes. |
| Jun 1 2007 01:22:20:273PM | 1070601017 | Robert Granetz | Shot 17 -- Fizzle. I guess a 1.2 MA disruption takes more than one fizzle to recover. Next shot: try again with no changes. |
| Jun 1 2007 01:37:18:260PM | 1070601018 | Robert Granetz | Shot 18 -- Plasma. Good shot. Still ohmic. Next shot: change SSEP to -3 mm. |
| Jun 1 2007 01:51:59:967PM | 1070601019 | Robert Granetz | Shot 19 -- Plasma. Good shot. Next shot: switch to USN (seg 3), except copy Ip, nl_04, IC_EF4U, and pre-programmed gas voltage from seg 4 to corresponding wires in seg 3. Turn on seg 3 and turn off seg 4. |
| Jun 1 2007 02:07:08:090PM | 1070601020 | Robert Granetz | Shot 20 -- Plasma. Good shot. Upper null. The real-time video image showed the plasma getting very dim...a very visual indication of the strong pumping that occurs in the upper null configuration. Next shot: go back to near-DN (reload shot 19). TURN ON ICRF to get an H-mode. Program nl_04 and PG3 to go to zero after t=0.5 s (was after 0.8 s). |
| Jun 1 2007 02:20:17:073PM | 1070601021 | Robert Granetz | Shot 21 -- Plasma. Good shot. 3 H-modes. Prf=2 MW (D+E). Cryopump was cold, and pumping the upper chamber well, but it didn't seem to pump the plasma density much. Next shot: Cryopump warm; program nl_04 to 0.9e20 m-2 for the whole shot. RF on. |
| Jun 1 2007 02:25:31:200PM | 1070601022 | Robert Granetz | Shot 22 -- Fizzle. I didn't shorten the pre-fill, even though the cryopump is not on. But the prefill pressure is only 0.06 mTorr, which would normally have been fine. Next shot: reduce pre-fill by 10 ms. |
| Jun 1 2007 02:52:33:470PM | 1070601023 | Robert Granetz | Shot 23 -- Plasma. Good shot. Long steady H-mode. Prf=2.0 MW and long, steady. Cryopump was warm. Next shot: Cryopump cold; zero the density programming after t=0.6 s. Add 10 ms to prefill to compensate for cryopump being on. |
| Jun 1 2007 03:10:00:843PM | 1070601024 | Robert Granetz | Shot 24 -- Plasma, but disrupted very early (0.26 s). I think it was an impurity problem. Next shot: repeat, no changes except turn on argon (not krypton) for 100 ms. |
| Jun 1 2007 03:27:21:373PM | 1070601025 | Robert Granetz | Shot 25 -- Plasma. Disrupted at t=1.26 s (in flattop at 1.0 MA). Looks like a vertical stability problem, even though N/Ncrit << 1.0. No power supply problems. Should have been no problem. Next shot: jog SSEP to +0.005 m at t=0.7. Change CLEARIN wire to modify the ZXU keyword parameter after t=0.75 s. |
| Jun 1 2007 03:33:38:983PM | 1070601026 | Robert Granetz | Shot 26 -- No-power shot due to MDS cycle problem. |
| Jun 1 2007 04:00:46:860PM | 1070601027 | Robert Granetz | Shot 27 -- Dud. OH1 didn't commutate. Next shot: try, try again. |
| Jun 1 2007 04:15:26:580PM | 1070601028 | Robert Granetz | Shot 28 -- Fizzle. Post-disruption recovery (shot 25, 1 MA disruption). Next shot: no changes |
| Jun 1 2007 04:33:04:703PM | 1070601029 | Robert Granetz | Shot 29 -- Plasma. Good shot. Nice changeover from LSN to USN at t=0.7 s. Density clearly starts pumping out nicely at t=0.7 s, and continues through the entire flattop. But the ICRF didn't go. Next shot: increase SSEP job to +10 mm at t=0.85 s. Try again with ICRF. |
| Jun 1 2007 04:52:43:093PM | 1070601030 | Robert Granetz | Shot 30 -- Plasma. Good shot. Disrupted in rampdown. SSEP ramp was not as good as the previous shot, even though I programmed it for higher SSEP (10 mm). Lots of H-modes while the plasma was (barely) upper null. Prf=1-2 MW. Next shot: Go to upper null (turn on seg 3, turn off seg 4). Copy nl_04, Ip, PG3, and PG1 from seg 4 to seg 3. |
| Jun 1 2007 05:04:04:817PM | 1070601031 | Robert Granetz | Shot 31 -- Plasma. Good shot. USN. Steady 2 MW of ICRF, but no H-modes. Good cryopump pumping (including an obvious dimming on the video). But we want both...H-modes and pumping. Next shot: go back to near DN with an SSEP ramp up to 5 mm, similar to shot 29. Start SSEP at 0.000 instead of -3 mm. |
| Jun 1 2007 05:15:15:380PM | 1070601032 | Robert Granetz | Shot 32 -- Plasma. Good shot. Disrupted at t=1.44 s at Ip=1.0 MA. Lots of short H-modes, but SSEP didn't ramp very well, so the plasma was only weakly upper-null. No obvious pumping on the density. End of run. I turned off the DPCS_FTAE2 pro in the DPCS interface and loaded it. |
| Engineering Operator Comments | ||||
| Shot | Time | Type | Status | Comment |
| 1 | 09:06:46:050AM | Test | Ok | |
| 2 | 09:20:10:110AM | Test | Ok | |
| 3 | 09:38:29:683AM | Plasma | Ok | |
| 4 | 10:06:04:547AM | Plasma | Ok | |
| 5 | 10:20:17:870AM | Plasma | Ok | |
| 6 | 10:33:52:073AM | Plasma | Ok | |
| 7 | 10:48:43:887AM | Plasma | Ok | |
| 8 | 11:03:18:323AM | Plasma | Ok | |
| 9 | 11:18:19:597AM | Plasma | Ok | |
| 10 | 11:33:58:033AM | Plasma | Ok | |
| 11 | 11:47:07:463AM | Plasma | Ok | |
| 12 | 12:01:06:823PM | Plasma | Ok | |
| 13 | 12:17:46:693PM | Plasma | Ok | |
| 14 | 12:31:45:600PM | Plasma | Ok | |
| 15 | 12:44:33:773PM | Plasma | Ok | |
| 16 | 12:59:47:237PM | Plasma | Ok | |
| 17 | 01:12:38:643PM | Plasma | Ok | |
| 18 | 01:25:02:773PM | Plasma | Ok | |
| 19 | 01:39:27:340PM | Plasma | Ok | |
| 20 | 01:53:19:277PM | Plasma | Ok | |
| 21 | 02:08:00:590PM | Plasma | Ok | |
| 22 | 02:21:20:153PM | Plasma | Ok | |
| 23 | 02:33:57:600PM | Plasma | Ok | |
| 24 | 02:59:46:250PM | Plasma | Ok | |
| 25 | 03:13:27:157PM | Plasma | Ok | |
| 26 | 03:28:05:517PM | Plasma | Bad | No Power Act Mon problem |
| 27 | 03:57:50:347PM | Plasma | Ok | |
| 28 | 04:10:23:203PM | Plasma | Ok | |
| 29 | 04:22:56:893PM | Plasma | Ok | |
| 30 | 04:40:33:597PM | Plasma | Ok | |
| 31 | 04:52:58:500PM | Plasma | Ok | |
| 32 | 05:05:42:643PM | Plasma | Ok | |
| System Availability | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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