| Miniproposals | ||||||||||
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| Operators | |
| Session leader(s): | Chuck Kessel |
| Physics operator(s): | Ian Hutchinson |
| Engineering operator(s): | Bill Cochran,Bill Parkin,Ed Fitzgerald |
| Engineering Operator Run Comment |
| MP698 ITER-like plasmas |
| Session Leader Plans |
| Entered: Jul 16 2012 08:59:50:337PM |
| Author: Chuck Kessel |
| Run Plan for MP698 ITER-like Discharges at 2.7 T
1 psi Argon in H-BOT 2 psi Neon in B-SIDE LOWER Target is to obtain sustained flattop q95 = 3, kappa = 1.80, betaN = 1.7-1.9, n/nGr = 0.85, and H98 ~ 1.0 in EDA H-mode, simultaneously, by increasing P(net) = P(IC) + P(OH) â?? dW/dt â?? P(rad) through increased P(IC) and controlled P(rad) with Neon seeded impurity Reference discharge is 1110104036, or 029 for very similar discharge with no rampup ICRF. Obtain Bt = 2.7 out to 2.0 s, see PO plan for discharge modifications 1) Recover 036 (or 029) performance, keeping all settings the same 2) Shift on-time for ICRF to 600 ms, maintaining early shape of P(ICRF) and blending into power ramp, AND make rampdown power levels 1.5 MW from 1.5 to 1.75 s, and 1.0 MW from 1.75 to 2.0 s. â?? if rampdown provides a tuning issue and affects power levels in flattop, then remove rampdown ICRF power and terminate H-mode ~ 150 ms before end of flattop 3) Raise ICRF power uniformly across flattop power ramp by 0.5 MW (ICRF power is ramping throughout flattop phase, starting ~ 1.8 MW going to 3.0 MW in 1110104036 and 029, so change to 2.3 â?? 3.5 MW)â?¦anticipate ELM free H-mode 4) Introduce neon following Ip rampup from 400-600 ms, attempting to recover EDA, varying Neon injection amounts to vary radiated power, starting low and increasingâ?¦..possibly adjust ICRF to reach higher power earlier 5) same as above with 1.0 MW ICRF power increase over reference, adjust neon timing and amount 6) same as above with 1.5 MW ICRF power increase over reference, adjust neon timing and amount 7) same as above with 2.0 MW ICRF power increase over reference, adjust neon timing and amount if uniform ICRF power increase does not work, keep front end of ICRF power lower and ramp to larger values toward end of flattopâ?¦.explore different trajectories |
| Physics Operators Plans |
| Entered: Jul 16 2012 02:59:47:997PM |
| Author: Ian Hutchinson |
| MP698 ITER-like plasmas.
Boronization: Yes. Overnight. Use standard operating parameters. ECDC: 2 hours He at 5e-5torr. Power systems as on: 1110104036 Acoil: +Dtop -Dbot -Jtop +Jbot (standard) Hybrid Enabled Gas setup: [Note non-standard NEON and ARGON locations.] Fill B-Top with 6 psi D2 Hybrid enabled (PG4) fill B-side lower with 2 psi NEON 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 10 psi D2 DISABLED fill H-bottom with 2 psi ARGON Hybrid DISABLED (PG5) Enable gate-valves and shutters: ECE, VUV, HiREX Sr, Xeus/LoWEUS Leave z-bolo shutter as is (should be open) Torvac gatevalve toggle (yes/no): no ICRF(yes/no): yes LH(yes/no): no Cryopump (yes/no): no DNB (yes/no): not required, not excluded |
| Session Leader Summaries |
| Entered: Jul 17 2012 05:53:08:620PM |
| Author: Chuck Kessel |
| Successful run day pushing to higher n/nGr, at high betaN and ITER-like parameters, although attempts to follow the previous data trend to higher H98 by raising Pnet/n did not materialize. There are parts of the discharges with good combinations of H98,betaN,n/nGr with higher Pnet/n, with H98 up to 0.85, but the highest n/nGr appear to have lower H98 = 0.6-0.70. Neon attempts were not conclusive, and it is not clear that we are using it properly...have the proper conditions to make it help. Radiated power were low on this runday, so we were not wresting against much higher radiated powers with rising ICRF power. ICRF reached 4.25 MW steady, and we started using a slow rampup, similar to 1110104 for the front end, with a steady phase from 1.0-1.5 s. It took some time to bring up the ICRF, and a little trouble with J, but soon the ICRF was providing good waveforms.
Discharge development included aligning rampup and rampdown with associated ITER current diffusion times. The elongation was increased up to 1.75, but we needed to avoid losing the edge Thomson last point. Cross-over was smoothed out extremely well. Raised reference n at end of ramp to nl04 = 0.9x10^20, compared to 0.75x10^20 from 1110104 Lots of effort in ICRF waveform to avoid an earlier H-mode that behaved as ELM-free, but was long lived in many cases. Moved away from continuous ramp in flattop like 1110104 to an early ramp with constant power later. good shots: 004, 006, 007, 008, 009, 010, 011, 012, 014, 015, 016, 018, 020, 021 shots 006-010: ICRF 2-3.5 MW, betan reaching 1.3-1.5, nl04 reaching 2.1e20 shots 11-16: ICRF 3.5-4.5 MW, betan reaching 1.7+, nl04 reaching 2.1e20 shots 18-21: ICRF reaching 4.25 MW, betan reaching > 2, nl04 reaching 2-2.1e20 |
| Physics Operator Summaries |
| Entered: Jul 17 2012 02:56:09:183PM |
| Author: Ian Hutchinson |
| Overview.
--------- Plasmas were not so cooperative as the last time (1110104) these low-B ITER like plasmas were run. With the exception of a couple of current ramp early deaths apparently caused by a radiative event, initiation was fine. The current ramp-up rate asked for was immediately obtained without difficulty. The faster ramp-downs were rather disruptive, but not apparently because of control issues. The optimal timing and pulse shape of the ICRF was not found in so complete a way as before. PO progress: ------------ OH crossover was a nuisance, but was alleviated eventually by putting a jink into clearin (rcur jinks did not work). Early diversion, at 0.1 s, was obtained and some tweaking in the first 0.1s was undertaken but because of the early termination and because of some operator errors, it was not carried through to completion. What is needed to help these plasmas to achieve even earlier diversion is to control the vertical position during the period 0.6-0.8 (segment 1) to keep the zcur from going positive. Incipient vertical instabilities at around 0.12s mean one has to be careful pushing any harder on elongation. Scorecard. ---------- Shot,Duration(s),Ipmax(MA),Result Shot,Duration(s),Ipmax,Result | 01 0.000 0.002 Dud | 02 0.633 0.637 Plasma | | 03 0.536 0.680 Plasma | 04 1.675 0.656 Plasma | | 05 0.000 0.089 Plasma | 06 1.576 0.656 Plasma | | 07 1.632 0.654 Plasma | 08 1.724 0.661 Plasma | | 09 1.771 0.662 Plasma | 10 1.660 0.658 Plasma | | 11 1.705 0.662 Plasma | 12 0.000 0.061 Plasma | | 13 1.056 0.709 Plasma | 14 1.806 0.671 Plasma | | 15 1.802 0.665 Plasma | 16 1.806 0.666 Plasma | | 17 1.628 0.663 Plasma | 18 1.823 0.664 Plasma | | 19 0.709 0.697 Plasma | 20 1.823 0.667 Plasma | | 21 1.822 0.665 Plasma Date 1120717: 21 shots. 20 plasmas. 0 fizzles. 1 duds. 0 System Error. Total plasma duration: 27.19 s (exceeding -100 kA) |
| Session Leader Comments | |||
| Jul 17 2012 11:11:14:870AM | 1120717009 | Chuck Kessel | GOOD progress on discharge, rampup established, long flattops, and rampdown getting longer. Reaching n/nGr = 0.85 target and high betaN = 1.8-2.0, however H98 is 0.6. ICRF working better, long ramps in flattop....establishing rampdown ICRF. Used higher power shift in flattop of 0.5 MW....getting ELM-free with longish H-modes |
| Jul 18 2012 12:09:50:247PM | 1120717010 | Darin Ernst | PLAN: attempt to reduce nl04 to 0.3
resume ninja and lbo |
| Jul 17 2012 12:04:35:067PM | 1120717011 | Chuck Kessel | good n/nGr and betaN, but H98 still low....have an early ELM-free like phase although QCM may be there, while second phase is EDA H-mode, steady, and shows the 10KHz MHD we saw in 1110104. working with ICRF waveform to get as much high power flattop phase as possible, but get rid of ELM-free/radiation in earlier phase |
| Jul 17 2012 12:48:55:073PM | 1120717015 | Chuck Kessel | getting good rampdowns with full ICRF power request there of 1.5 - 1.0 MW. Trying to remove the early ELM-free thing STILL. Slower ICRF rise. ICRF is hitting voltage limits at 4.5MW, so will back off slightly. H98 is rising slightly if you are an optimist and like transients. |
| Jul 17 2012 01:28:52:007PM | 1120717017 | Chuck Kessel | Trying to get the high power phase of ICRF to come in smooth, problems with J. |
| Jul 17 2012 02:11:58:197PM | 1120717020 | Chuck Kessel | shots are all the way thru rampdown, ICRF getting cleaner, still fiddling with the early H-mode...018 was interesting, little lower n/nGr, higher H98 about 0.7-0.8. Tried neon pn 019, and Matt lost the bet...will try again |
| Physics Operator Comments | |||
| Jul 16 2012 08:37:14:047AM | Ian Hutchinson | Working on setup for the Kessel Run MP698. First Chuck's list:
Reference discharge is 1110104036â?¦.keep Bt constant through rampdown at 2.7 T 1) establish as an ohmic reference, nl04 target at end of Ip rampup 0.75x1020 /m2 2) attempt early divert, 80-100 ms or as early as possible 3) rampup time 250 ms, rampdown time 300 ms 4) total discharge time is 2.0 s 5) reach Ip at end of ramp and hold, tighter control 6) recover plasma elongation as close to 1.8 as possible (raise Ip slightly?) 7) ICRF on at 120 ms, 0.5 MW, to 250 ms 8) ICRF rising as 1110104036 from 250 â?? 1700 ms 9) ICRF from 1700 to 1850 ms 1.5 MW, 1850 to 2000 ms 1.0 MW 10) Recover 036 performance 11) Raise ICRF power uniformly across flattop power ramp by 0.5 MW (ICRF power is ramping throughout flattop phase, starting ~ 1.8 MW going to 3.0 MW in 1110104036, so change to 2.3 â?? 3.5 MW)â?¦anticipate ELM free H-mode 12) Introduce neon following Ip ramp from 250-450 ms, attempting to recover EDA, with following Neon injection amounts (scanning gas pressures to vary radiated power)â?¦..possibly adjust ICRF ramp to be weaker, reach higher power earlier a. 0.25 psi b. 0.50 psi c. 0.75 psi d. 1.0 psi e. etc. 13) same as above with 1.0 MW ICRF power increase over reference, adjust neon timing and amount 14) same as above with 1.5 MW ICRF power increase over reference, adjust neon timing and amount 15) same as above with 2.0 MW ICRF power increase over reference, adjust neon timing and amount if uniform ICRF power increase does not work, keep front end of ICRF power lower and ramp to larger values toward end of flattopâ?¦.explore different trajectories | |
| Jul 16 2012 10:27:12:047AM | Ian Hutchinson | Load from 1110104036
Zero segments 3 and 4. Call predictors in segments 1 and 2 Save as 71701 Examine TF current. The PCS demand in seg 2 is -70.8kA. This seems strange. We actually get -74.6kA which is about right. Why this big discrepancy? The shot from which this was loaded was 1100121036. I find that Wolfe had programmed this in during that run to get the right field. It's an offset. The point being addressed is that the field swings higher and then back down so that at 200ms, where the early RF turns on, the Bt is approximately 3T, ie. 10% too high. Add a point at 40ms with TF demand at 70.8kA and keep at that level in segment 1. The prior point at 30ms prevents any changes prior to that. This should get the TF to the required current roughly 80ms earlier. The field error at 200ms ought to be less than half the prior 10%. Extend the segment 2 TF flat top to 1.9s. Save as 71701. | |
| Jul 16 2012 10:57:38:723AM | Ian Hutchinson | Examining the factors controlling the elongation and diversion time.
The swing of OH2s and EF1s at segment 2 appears to be in response to the clearin feedback. ICEF1s and ICOH2s have zero gain in segment 1 after 0s. They are voltage programmed plus rcur/zcur. Basically the EF1V is held high at 200V, and the OH2 voltage is allowed to ramp down after the crowbar at 40ms. It looks to me as if the main issue is EF1 current to produce the x-point. ADJUSTMENT: EF1Vs ramp down after 40ms to zero at 80ms to allow earlier x-point formation. Save as 71702 | |
| Jul 16 2012 11:19:58:467AM | Ian Hutchinson | Ip Ramp Up.
Added a point at 80ms 285kA. Move ramp end from 370ms to 250ms. Ip Ramp Down. Shape evolution seems ok. Just make the current ramp faster. To zero at 1.85s. Save as shot 71703 | |
| Jul 16 2012 12:43:11:870PM | Ian Hutchinson | A ramp-down that ends at 2s but is faster.
Start Ip ramp at 1.65s. Adjust xu, xl programming to synchronize. This involves plenty of guess-work; so it is more risky than shot 71703. Save as 71704 | |
| Jul 17 2012 09:02:50:287AM | Ian Hutchinson | Load from scratch 71703, saved yesterday. Got a warning about PCS configuration.
Wolfe says that's all right. Load segment 3 from shot 71704 segment 2. This is the later rampdown. Leave off. Load. | |
| Jul 17 2012 09:42:13:237AM | 1120717002 | Ian Hutchinson | Plasma disrupts at .55s. Very similar to last shot, but a big density rise comes before the RF. We think it is an ohmic H-mode.
Delay RF. move rxl out at .28s. rcur to .661 at .4s. Load |
| Jul 17 2012 10:05:02:720AM | 1120717003 | Ian Hutchinson | Plasma disrupts at 0.65s. Much gas coming from RF. Seems to touch inboard at .5s.
Install the OH1 crossover Test_pro to speed up crossover. |
| Jul 17 2012 10:03:13:543AM | 1120717004 | Ian Hutchinson | Plasma to rampdown.
Slow the ramp of zxl in current rampdown to try to prevent going upper null. |
| Jul 17 2012 10:14:13:217AM | 1120717005 | Ian Hutchinson | Plasma dies in rampup at 100kA due to big density rise/brick.
Drop plasma zcur 1mm. Trying to get the edge TS on point. |
| Jul 17 2012 10:36:45:923AM | 1120717006 | Ian Hutchinson | Plasma to rampdown.
Ramp down Rxl more quickly in Ip rampdown. rcur to -2mm. Load. |
| Jul 17 2012 10:50:06:840AM | 1120717007 | Ian Hutchinson | Plasma to rampdown. Still has early elm-freeish h-mode
Install rcur jink at OH crossover time to try to fix crossover. Raise early RF 0.5MW. Raise zxu to .045 from .04 |
| Jul 17 2012 11:01:37:840AM | 1120717008 | Ian Hutchinson | Plasma to rampdown. The higher RF did not appear to be the way to go.
Kappa dropped a bit later. Increase the rcur jink to .666. Ramp zxl down to -.01 nl04 to .9e20 |
| Jul 17 2012 11:23:46:687AM | 1120717009 | Ian Hutchinson | Plasma to rampdown. Rcur jink is not working.
Lower zxl in initial Ip rampdown. Ramp zcur to -.005 in Ip rampdown. Remove rcur jink. Install a clearin jink. [Lower initial RF level.] Load |
| Jul 17 2012 11:49:50:850AM | 1120717010 | Ian Hutchinson | Plasma.
Start the clearin jink earlier. EF1V to 0 at 60ms. TF downswing started at 30ms. |
| Jul 17 2012 11:57:29:007AM | 1120717011 | Ian Hutchinson | Plasma to rampdown.
OH2V lowered to 40V at 60ms. Lower Rxl to -.001 at .6s increase clearin jink. |
| Jul 17 2012 12:10:54:013PM | 1120717012 | Ian Hutchinson | Ip ramp died at 60kA 28ms. |
| Jul 17 2012 12:24:46:103PM | 1120717013 | Ian Hutchinson | Plasma disrupts at 1.05s. This higher RF ramp to 4MW remains ELMfreeish and has
radiation problems that cause the disruption. Make the clearin jink more abrupt to .44s. Turn off crossover routine. OH2V to 30 at .6s Lower RXl to 0 at .4s. |
| Jul 17 2012 12:43:12:770PM | 1120717014 | Ian Hutchinson | Plasma through rampdown.
Rxl to -.005 at .2s from -.01. Trying to avoid incipient instability at .12s RF changes. |
| Jul 17 2012 12:50:58:663PM | 1120717015 | Ian Hutchinson | Plasma through rampdown.
Add segment 1 zcur point -.002 at .1s |
| Jul 17 2012 01:14:34:007PM | 1120717016 | Ian Hutchinson | Plasma through rampdown.
Step gain to 3.5 from 2.5 in segment 1 at 60ms. Correct the sign of the clearin jink to positive. |
| Jul 17 2012 01:26:33:407PM | 1120717017 | Ian Hutchinson | Plasma to rampdown.
Slow zcur gain to 4.5 at 60ms. |
| Jul 17 2012 01:44:53:093PM | 1120717018 | Ian Hutchinson | Plasma through rampdown.
zcur slow gain derivative term to 2 (from 1) at 60ms. PG1 at 50V 0.4 to 0.6s |
| Jul 17 2012 01:59:20:783PM | 1120717019 | Ian Hutchinson | Plasma disrupts at .7s.
Add more negative rcur in the 60-80ms segment 1. |
| Jul 17 2012 02:11:04:457PM | 1120717020 | Ian Hutchinson | Plasma through rampdown.
Find that I've been making adjustments in segment 1 to the wrong zcur controller. All the adjustments so far have been to the fast zcur. Now. Put a step up to gain of 1.5 at 60ms on slow zcur in segment 1. |
| Jul 17 2012 02:44:43:463PM | 1120717021 | Ian Hutchinson | Plasma through rampdown.
Move the derviative switch to 1 on slow zcur to .6s in segment 1. Enter EF3V point at 60ms 1000V. (Slight increase to push in.) Alternator bearing overheats. Run halt called. |
| Engineering Operator Comments | ||||
| Shot | Time | Type | Status | Comment |
| 1 | 06:57:54:550AM | Test | Ok | |
| 2 | 08:58:50:160AM | Plasma | Ok | |
| 3 | 09:17:27:657AM | Plasma | Ok | |
| 4 | 09:37:50:530AM | Plasma | Ok | |
| 5 | 09:57:05:010AM | Plasma | Ok | |
| 6 | 10:12:13:810AM | Plasma | Ok | |
| 7 | 10:26:59:880AM | Plasma | Ok | |
| 8 | 10:44:28:260AM | Plasma | Ok | |
| 9 | 11:03:12:663AM | Plasma | Ok | |
| 10 | 11:22:05:297AM | Plasma | Ok | |
| 11 | 11:41:12:790AM | Plasma | Ok | |
| 12 | 11:55:52:473AM | Plasma | Ok | |
| 13 | 12:08:31:320PM | Plasma | Ok | |
| 14 | 12:22:30:550PM | Plasma | Ok | |
| 15 | 12:35:41:767PM | Plasma | Ok | |
| 16 | 12:49:09:277PM | Plasma | Ok | |
| 17 | 01:08:26:537PM | Plasma | Ok | |
| 18 | 01:27:16:287PM | Plasma | Ok | |
| 19 | 01:41:25:063PM | Plasma | Ok | |
| 20 | 01:54:27:050PM | Plasma | Ok | |
| 21 | 02:09:09:833PM | Plasma | Ok | Alternater Fault after the shot |
| System Availability | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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