| Miniproposals | ||||||||||
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| Operators | |
| Session leader(s): | Brian Labombard |
| Physics operator(s): | Earl Marmar |
| Engineering operator(s): | Bill Parkin,Gary Dekow |
| Engineering Operator Run Comment |
| 2nd day of MP 267 - rev. field PO Marmar, SL LaBombard, EO Dekow/Parkin |
| Session Leader Plans |
| Physics Operators Plans |
| Session Leader Summaries |
| Entered: Jul 7 2004 03:49:25:400PM |
| Author: To Be Determined |
| 11/09/00 run: MP#267 - reversed field "Dependence of SOL Fluctuations and Particle Transport on Collisionality" - reversed field, Day 2 Session Leader - B. LaBombard Phys Op - E. Marmar ________________________________________________________________________________ Overall objectives of MP#267: "The purpose of these experiments is to explore the dependence of SOL fluctuation characteristics and attendant cross-field particle transport on the collisionality of the SOL." ________________________________________________________________________________ Reason for today's run: Reversed field/current allows some important measurements to be made on particle transport in the SOL and the associated levels of plasma turbulence. From a series of shots over ~2 run days we hope to do the following: (1) get data on SOL particle transport (using Ly-alpha diag.) in reversed field. Does the field direction affect the 'scaling' of Deff with collisionality? (2) get data on in-out asymmetries. The outer divertor conditions should change in reversed B. This may impact (1) through changes in the sheath conditions at the divertor plate (e.g., affecting the propagation velocity of the 'blobs' if they somehow involve the 'sheath impedance' via a theory such as that outlined recently by S. Krasheninnikov) (3) get data on field-reversed C2D4 plumes. ExB should now carry the plume away from the probe shaft, resulting in plumes that may be easier to interpret. The 'reversed flows' associated with low collisionality near the separatrix should now become 'normal flows' with reversed B. This should be interesting for the plumes. The magnitude of Er in reversed B is of interest also. (4) get fluctuation data from scanning probe and fast diodes systems. Is the SOL plasma fluctuation character the same in reversed B? ________________________________________________________________________________ Run Plan: Today's run was to cover the Day 2 plan outlined in MP#267: Day 2: Coarse density scans at different reversed plasma currents and reversed toroidal fields Start with reload of shot#1001103022 which was a recent 0.8 MA, 5.3 tesla, NL04 = 0.75 discharge (reversed Ip and Bt) with good probe targeting, gaps etc. Then change plasma current to 0.53 MA and NL04 = 0.5x10^20 m^-2. Take two shots at each condition to optimize scanning probe insertion depths. Shot#4,5 - NL04 = 0.5, Ip = 0.53, Bt = 5.3 6,7 - NL04 = 0.7, Ip = 0.53, Bt = 5.3 8,9 - NL04 = 0.9, Ip = 0.53, Bt = 5.3 10,11 - NL04 = 1.0, Ip = 1.06, Bt = 5.3 12,13 - NL04 = 1.3, Ip = 1.06, Bt = 5.3 14,15 - NL04 = 0.7, Ip = 1.06, Bt = 5.3 16,17 - NL04 = 0.6, Ip = 0.8, Bt = 4 18,19 - NL04 = 0.9, Ip = 0.8, Bt = 4 20,21 - NL04 = 1.2, Ip = 0.8, Bt = 4 22,23 - NL04 = 1.2, Ip = 0.8, Bt = 6 24,25 - NL04 = 0.9, Ip = 0.8, Bt = 6 26,27 - NL04 = 0.6, Ip = 0.8, Bt = 6 ________________________________________________________________________________ Results: Thanks to the extra efforts of Tom and Felix, the computer systems were well enough today to have a functional run, despite the disk hardware failure the day before. We got 11 usable reversed field plasmas today. We were able to make use of 8 of these shots which had good separatrix positioning with scanning probes operating near the separatrix. We managed to complete 1/2 of the run plan which primarily consisted of two rough density scans at two different plasma currents (0.5 and 1.0 MA). We did not have time to attempt the B-field scan portion of this MP. Since this part of the MP is critical for sorting out the difference between Ip and q scaling, we will be begging for more run time next week. The turbulence imaging camera was back on line today, recording the usual 'blobs' with 0.5 usec exposure (this time in HeI light) in the far SOL. We should be able to get a good comparison of 'blob statistics' between the 0.5 and 1.0 MA data on this run. Sanjay got more plumes for his stamp collection today. Again, the ExB flow indicated on some of the plumes were clearly opposite to what we had expected. These results show that we don't really understand the potential profiles in the SOL as well as we thought and may provide some insight into the physics that determines the radial electric fields in the SOL. There is also the possibility that the probe itself is influencing the ExB flows in a way that is confusing our interpretation. Clearly there will be a lot of analysis to be performed on these plumes once we finish collecting the reversed field data. Shots 11 and 13 today had a very interesting 'fueling event' associated with the 'marfe' moving into the upper chamber at around 1.2 seconds. These were 0.5 MA plasmas in which we were trying to maintain NL04 ~ 0.7. Helium was being puffed on these shots also. At around 1.2 seconds the core plasma density shot up to NL04 ~ 1.2 very fast. At the same time the midplane and upper chamber pressures started to rise. The divertor pressure also started to fall. Later in the event the upper chamber and lower divertor pressures become about equal. Chris's A-port survey camera shows that prior to this event, there appears to be a lot of neutrals (very bright D-alpha light) under and around the inner divertor nose region. Just after the event, the bright D-alpha light almost completely disappears, suggesting that these neutrals got dumped into the core plasma very quickly and caused the density rise. The change in hydrogen inventory in the chamber supports this view: the core density rise can not be explained by a drop in neutral pressure in the top, midplane, and divertor locations. Apparently a lot of neutrals can be stuffed into the inner divertor region - a location where there is no pressure gauge! Rejean also sees that before the 'event' the Ly-alpha is optically thick on the midplane, while after the 'fueling event' the Ly-alpha signal appears to not be optically thick. This observation is consistent with a dramatically decreased neutral density at the inner midplane following the event. The East probe (or its coaxial cable) on the ASP still continues to give us trouble. The probe exhibited intermittent short-circuit behavior again today. ________________________________________________________________________________ Shot Notes: Setup for all shots: ASP and FSP scanning times set at .7, .95, and 1.2 s ASP E-W in swept single probe mode, N-S in floating mode Setup before shot#19 FSP E-W in swept DOUBLE probe mode, N-S in floating mode Setup for shot#19+ FSP E-W in swept SINGLE probe mode, N-S in floating mode Shot 7 - First full length shot., NL04 ~ 0.5 ASP and FSP scanning outside LCFS, no plumes Shot 8 - NL04 ~ 0.5, Ip = 0.5 MA Plumes, but camera not triggered Shot 9 - NL04 ~ 0.5, Ip = 0.5 MA FSP not scanning! (no trigger) Shot 11 - NL04 ~ 0.7 jumps to 1.2 (poloidal detachment?) at 1.18 sec , Ip = 0.5 MA C2D4 plumes Shot 13 - NL04 ~ 0.7, again jumps to 1.2 (poloidal detachment?) at 1.22 sec , Ip = 0.5 MA Better outer gap ASP and FSP scanning at .7, .95, and 1.2 s C2D4 plumes Shot 14 - NL04 ~ 0.5 to .58, Ip = 0.5 MA ASP and FSP scanning at .7, .95, and 1.2 s C2D4 plumes Shot 15 - NL04 ~ 0.4, Ip = 0.5 MA He puff off ASP and FSP scanning at .7, .95, and 1.2 s C2D4 plumes, deep insertion. Shot 16 - 1.0 MA attempt. Disrupts at first probe scan. ASP and FSP too deep! Shot 18 - 1.0 MA, NL04 ~ 0.7 Looks like there is a problem with the FSP - perhaps east probe is shorted. C2D4 plumes Shot 19 - 1.0 MA, NL04 ~ 0.7 ramping (from He puff) to 1.0 He puff on FSP working again with E & W in single sweep mode. C2D4 plumes Shot 20 - 1.0 MA, NL04 ~ 1 FSP working again with E & W in single sweep mode. C2D4 plumes Shot 22 - 1.0 MA, NL04 ~ 1.2 to 1.3 FSP working again with E & W in single sweep mode. Good data. C2D4 plumes |
| Physics Operator Summaries |
| Entered: Jul 7 2004 04:37:12:647PM |
| Author: To Be Determined |
| Physop run summary 1001109 Second day of MP#267 - reversed field "Dependence of SOL Fluctuations and Particle Transport on Collisionality" _______________________________________________________________________________ Engineering setup and run plan for Thursday 09 Nov 2000. PO - Marmar SL - LaBombard EO - Dekow/Parkin ECDC in D2 overnight, ending 2 hours before the run. Run starts at 09:00 and ends at 17:00, assuming the computers are fixed. Power systems as on 1001103022. 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, for ECDC fill C-side with 30 psi of D2 Hybrid enabled leave J-bot as is Hybrid DISABLED The following gate valves should be enabled: ECE, VUV, Beast _____________________________________________________________________________ ECDC in D2 had been run for most of the day yesterday, and overnight, stopping at 7:00 am. There were no computer or power supply problems today. Thanks are due to the computer gurus who burned the midnight oil (and beyond) last night to fix things after the computer melt-down(s) of the previous 2 days. The machine ran quite well today. Startups were often bouncing, or breaking down late, but after some early wirehead tweaking following 3 fizzles, we managed 14 plasmas out of 17 additional tries. The change that probably helped the most was moving the EFC turn-on time earlier by 10 msec, starting with shot 6. Physops can incorporate this into their startup by: 1) having the engineering operator set the EFC start time to -0.04 seconds; 2) Turning the EFC voltage on starting at +.010 seconds (as in 1001109006, segment 1, all V's). This appeared to solve the early vertical lurches which killed the first 3 fizzles. Minor changes to BR_0 may also have helped. Shot 21 (the second last of the day) was a mystery dud; the fields and gas all looked ok to me. Scorecard: 14 plasmas 5 fizzles 1 dud 2 tests _________ 22 cycles |
| Session Leader Comments | |||
| Nov 9 2000 11:05:00:623AM | 1001109007 | Brian Labombard | Shot 7 - First full length shot., NL04 ~ 0.5 ASP and FSP scanning at .7, .95, and 1.2 s ASP setup: N,S - Vf, E,W - single probe sweep mode FSP setup: N,S - Vf, E,W - double probe sweep mode ASP and FSP scanning outside LCFS Next shot - repeat with FSP and ASP to separatrix. |
| Nov 9 2000 11:21:43:763AM | 1001109008 | Brian Labombard | Shot 8 - NL04 ~ 0.5, Ip = 0.5 MA ASP and FSP scanning at .7, .95, and 1.2 s ASP and FSP scanning to LCFS C2D4 on but camera trigger was not! Next shot - repeat with camera on and ASP pulled back 2 mm. |
| Nov 9 2000 11:46:16:497AM | 1001109009 | Brian Labombard | Shot 9 - NL04 ~ 0.5, Ip = 0.5 MA ASP scanning at .7, .95, and 1.2 s Somehow FSP got disabled on the previous shot. C2D4 on but FSP was not scanning! Next shot - Go to NL04 ~ 0.7 with FSP and 'plumes' on |
| Nov 9 2000 12:47:28:543PM | 1001109011 | Brian Labombard | Shot 11 - NL04 ~ 0.7 jumps to 1.2 (poloidal detachment?) at 1.18 sec , Ip = 0.5 MA ASP and FSP scanning at .7, .95, and 1.2 s C2D4 plumes Next shot -Repeat with deeper ASP and more constant outer gap |
| Nov 9 2000 01:28:55:513PM | 1001109013 | Brian Labombard | Shot 13 - NL04 ~ 0.7, again jumps to 1.2 (poloidal detachment?) at 1.22 sec , Ip = 0.5 MA ASP and FSP scanning at .7, .95, and 1.2 s C2D4 plumes Next shot - go to NL04 ~ 0.4 |
| Nov 9 2000 01:57:36:530PM | 1001109014 | Brian Labombard | Shot 14 - NL04 ~ 0.5 to .58, Ip = 0.5 MA ASP and FSP scanning at .7, .95, and 1.2 s C2D4 plumes Next shot - try again for NL04 ~ 0.4, this time with He puff off. |
| Nov 9 2000 02:27:07:090PM | 1001109015 | Brian Labombard | Shot 15 - NL04 ~ 0.4, Ip = 0.5 MA ASP and FSP scanning at .7, .95, and 1.2 s C2D4 plumes, deep insertion. Next shot - go to Ip = 1.0 MA, NL04 = 0.7 |
| Nov 9 2000 02:48:34:763PM | 1001109016 | Brian Labombard | Shot 16 - Disrupts at first probe scan. ASP and FSP too deep! Next shot - try again, 1.0 MA, NL04 = 0.7 with probes pulled back |
| Nov 9 2000 03:40:42:780PM | 1001109018 | Brian Labombard | Shot 18 - 1.0 MA, NL04 ~ 0.7 ASP and FSP scanning at .7, .95, 1.2 seconds Looks like there is a problem with the FSP - perhaps east probe is shorted. C2D4 plumes Next shot: change to single sweep probe on E and W Next shot - Repeat with ASP deeper and He puff on. |
| Nov 9 2000 04:05:52:733PM | 1001109019 | Brian Labombard | Shot 19 - 1.0 MA, NL04 ~ 0.7 ramping (from He puff) to 1.0 ASP and FSP scanning at .7, .95, 1.2 seconds FSP working again with E & W in single sweep mode. C2D4 plumes Next shot - Go to NL04 ~ 1.0 |
| Nov 9 2000 04:36:21:233PM | 1001109020 | Brian Labombard | Shot 20 - 1.0 MA, NL04 ~ 1 ASP and FSP scanning at .7, .95, 1.2 seconds FSP working again with E & W in single sweep mode. C2D4 plumes Next shot - Go to NL04 ~ 1.3 |
| Nov 9 2000 05:06:28:543PM | 1001109022 | Brian Labombard | Shot 22 - 1.0 MA, NL04 ~ 1.2 to 1.3 ASP and FSP scanning at .7, .95, 1.2 seconds FSP working again with E & W in single sweep mode. Good data. C2D4 plumes End of run |
| Physics Operator Comments | |||
| Nov 9 2000 08:30:34:327AM | Earl Marmar | Engineering setup and run plan for Thursday 09 Nov 2000. Second day of MP#267 - reversed field "Dependence of SOL Fluctuations and Particle Transport on Collisionality" PO - Marmar SL - LaBombard ECDC in D2 overnight, ending 2 hours before the run. Run starts at 09:00 and ends at 17:00, assuming the computers are fixed. Power systems as on 1001103022. 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, for ECDC fill C-side with 30 psi of D2 Hybrid enabled leave J-bot as is Hybrid DISABLED The following gate valves should be enabled: ECE, VUV, Beast | |
| Nov 9 2000 09:02:37:797AM | Earl Marmar | Coldstart All matrices respond no errors | |
| Nov 9 2000 09:02:55:843AM | 1001109001 | Earl Marmar | no power test to check computers |
| Nov 9 2000 09:04:11:200AM | 1001109002 | Earl Marmar | no power test to check computers |
| Nov 9 2000 09:30:25:107AM | 1001109003 | Earl Marmar | load segment 1 from 1001106021 segment 2 from 1001102020 reduce flattop current to 0.5 MA reduce prefill puff to 20 msec (from 22) fizzle |
| Nov 9 2000 09:53:11:093AM | 1001109004 | Earl Marmar | reduce B_R offset to .002 from .0025 fizzle |
| Nov 9 2000 10:17:03:077AM | 1001109005 | Earl Marmar | increase prepuff by 2 msec, to 22 msec fizzle seem to be losing it vertically |
| Nov 9 2000 10:36:55:217AM | 1001109006 | Earl Marmar | move chopper voltage turn-on time earlier by 10 msec move EFC start earlier by 10 msec reduce B_R offset by 0.5 mT plasma disrupt at 0.53 s need to move I_p gain jump later |
| Nov 9 2000 11:21:57:437AM | 1001109007 | Earl Marmar | move I_p gain change later plasma disrupt during RF |
| Nov 9 2000 11:22:19:750AM | 1001109008 | Earl Marmar | Ramp current down sooner and a little farther plasma |
| Nov 9 2000 11:45:53:530AM | 1001109009 | Earl Marmar | Add 1 msec to prepuff plasma getting an early bounce, and some hards |
| Nov 9 2000 04:08:25:250PM | 1001109010 | Earl Marmar | increase nl_04 target to .7e20 seg 1 EF4 current reduced by 5 Amp before t=0 plasma disrupt at 0.558 |
| Nov 9 2000 12:37:57:170PM | 1001109011 | Earl Marmar | move plasma down by 1 cm shrink inner and outer gaps by 3 mm plasma strange density rise after 1.2 s |
| Nov 9 2000 01:05:01:403PM | 1001109012 | Earl Marmar | move plasma up .5 cm tweak RCUR between 0.8 and 1.2 seconds to keep outer gap more constant fizzle; late breakdown |
| Nov 9 2000 01:27:25:497PM | 1001109013 | Earl Marmar | reduce prepuff by 1 msec plasma |
| Nov 9 2000 02:03:48:310PM | 1001109014 | Earl Marmar | nl_04 to 0.4e20 plasma density was higher than desired, and may have been affected by the He puff bouncing hard on the outer wall during startup no hard x-rays on the BGO detector |
| Nov 9 2000 02:23:13:577PM | 1001109015 | Earl Marmar | turn off A-B limiter He puff tweak ZXU to try to keep it more constant plasma |
| Nov 9 2000 02:39:16:967PM | 1001109016 | Earl Marmar | I_p to 1 MA EF4 target to -3kA during flattop nl_04 to 0.7e20 plasma disrupt at first probe injection |
| Nov 9 2000 03:03:52:200PM | 1001109017 | Earl Marmar | Decrease RCUR by 1 mm fizzle late breakdown |
| Nov 9 2000 03:34:28:497PM | 1001109018 | Earl Marmar | BR_0 increase by 0.5 mT to .002 T plasma late breakdown, but it went anyway |
| Nov 9 2000 03:57:41:280PM | 1001109019 | Earl Marmar | decrease RCUR slightly during flattop plasma |
| Nov 9 2000 04:31:51:403PM | 1001109020 | Earl Marmar | nl_04 target to 1.0e20 plasma |
| Nov 9 2000 04:50:49:670PM | 1001109021 | Earl Marmar | nl_04 to 1.3e20 dud no obvious problems with fields or gas |
| Nov 9 2000 05:02:57:997PM | 1001109022 | Earl Marmar | no PCS changes Plasma disrupt at 1.37 s, during RF |
| Engineering Operator Comments | ||||
| Shot | Time | Type | Status | Comment |
| 1 | 08:20:14:513AM | Test | Bad | No Big Board Update |
| 2 | 09:02:24:577AM | Test | Ok | NO POWER TEST |
| 3 | 09:22:30:560AM | Plasma | Ok | |
| 4 | 09:47:01:233AM | Plasma | Ok | |
| 5 | 10:00:27:450AM | Plasma | Ok | |
| 6 | 10:22:32:373AM | Plasma | Ok | |
| 7 | 10:46:14:437AM | Plasma | Ok | |
| 8 | 11:09:33:607AM | Plasma | Ok | |
| 9 | 11:33:54:763AM | Plasma | Ok | |
| 10 | 12:00:16:467PM | Plasma | Ok | |
| 11 | 12:23:35:857PM | Plasma | Ok | |
| 12 | 12:49:29:200PM | Plasma | Ok | |
| 13 | 01:12:22:513PM | Plasma | Ok | |
| 14 | 01:40:48:907PM | Plasma | Ok | |
| 15 | 02:05:52:327PM | Plasma | Ok | |
| 16 | 02:32:30:247PM | Plasma | Ok | |
| 17 | 02:58:54:937PM | Plasma | Ok | |
| 18 | 03:22:14:263PM | Plasma | Ok | |
| 19 | 03:50:07:390PM | Plasma | Ok | |
| 20 | 04:16:26:793PM | Plasma | Ok | |
| 21 | 04:41:28:703PM | Plasma | Ok | |
| 22 | 04:58:29:717PM | Plasma | Ok | |