| Miniproposals | ||||||||||
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| Operators | |
| Session leader(s): | Amanda Hubbard |
| Physics operator(s): | Robert Granetz |
| Engineering operator(s): | Bill Cochran |
| Engineering Operator Run Comment |
| MP 363 H-mode power threshold in various configurations+ Pre-boronizatio |
| Session Leader Plans |
| Physics Operators Plans |
| Session Leader Summaries |
| Entered: Jul 7 2004 03:49:01:600PM |
| Author: Amanda Hubbard |
Session leader's Run Summary 1040106 Session Leader: Amanda Hubbard Phys. Op: Bob Granetz RF Ops: Yijun Lin Eng. Ops: Bill Cochran MP 363: Investigation of L-H Threshold conditions in LSN, DN, USN and limiter confugurations. This run continued, and completed, the run plan for this MP, following up on the run of 1031125. First run of the new year, in a machine in need of boronization. All considered, it went very well and accomplished the main purposes of the day. Started by repeating shots of Step 2: Lower Single Null. (Shots 3-10) Loaded shape, conditions of 1031125008, to check threshold was the same. Not surprisingly, it took a few shots to retune the RF. Threshold was indeed very similar, perhaps marginally higher. Shot 7, with 850 kW RF in the steady period, did not transition to H-mode until the ramp, at 1.3 MW. Shots 9 and 10, with 940 kW, transitioned quite early thus bracketing the threshold power to 900 +-50 kW. A secondary goal was to get GPC data in this configuration, which was missing on 1031125. Note that Bt was changed slightly between shots 7 and 9, moving channels inward. L-H transition occurred at Te8=315 eV (r/a 0.88) and Te9=135 eV (r/a=0.98). Then went to Step 5: Inner wall Limited (Shots 11-20) Went to shape from 1031125033, limited on inner wall at midplane, with elongation 1.4 and 12 mm outer gap. This configuration proved to have an extremely high L-H power threshold. We ran a series of shots with RF power up to 5.8 MW, at a range of densities. Only one, shot 18, with 5.2 MW RF, had indications of H-mode. This discharge had two brief periods at 0.857-0.874 s and 0.945-0.96 secs (at full RF power), as evidenced by TCI, ECE, ETS pedestals, BOLO and most obviously by changes in RF loading. The latter tripped the RF, which was why the H-modes were so short. Assuming 80 percent absorption and adding ohmic power, Ptot was 5.0 MW, as compared to 1.3 MW at threshold in LSN (ie 3.8 times higher); this is more than in either DN or USN configurations. The H-mode was certainly not robust; repeats of the shot (20 and 27) remained in L-mode despite slightly higher power (5.8 MW). It was noted that all the inner wall limiter shots had strong outgassing proportional to the RF power. Although the nominal target plasma of shot 18 had the same target density (nel 9e19 m-2) as shot 10, the density rose to 1.24e20 m-2 by the time of the L-H transition. To test whether this was responsible for the higher threshold, we scanned the target density progressively downward, while raising RF power to 5.8 MW. (Shots 21-26). All stayed in L-mode, though we got the density with RF down to the 9e19 m-2 level. The lowest density shots (23, 25) were very radiative and had high Zeff. There thus does not appear to be an operating window for inner wall limited H-modes on C-mod with the current wall conditions and available RF. John Rice reports that core rotation was strongly counter in limited ohmic plasmas, rising with RF power to be somewhat co-rotating, even in shots which didn't transition. Edge Te's rose during RF, with Te8 =450 eV at threshold (r/a =0.86) and Te9=212 eV (r/a=0.95). Further analysis and comparison of edge profiles, rotation and flows (including probes and Chromex) with other configurations is required. An interesting question is whether the much higher L-H threshold is due to the material interaction or the different flow patterns. To test this, we ran two discharges with the plasma limited near the bottom of the vessel, at the inner 'nose' plate. (shots 28 and 29). Shot 29 had a clean RF ramp and transitioned at 1.08 MW RF, approximately the same value as in LSN diverted plasmas! This interesting configuration is worth revisiting as we did not have time for full probe measurements. The remainder of the day (shots 30-35) was devoted to preboronization fiducucials and outgassing shots; see Physop summary for details. A very interesting run day; thanks to operators, RF, and diagnosticians. This completes the run plan of MP 363 (though it has spurred follow-up proposals). It also provides the data to complete part of a Level I milestone, comparing thresholds in LSN, DN, USN and limiter plasmas. Some good shots for further analysis (in addition to those on 1031125): LSN: L-mode, steady 850 kW (just below threshold): 1040106007 L-H transition, 950 kW: 1040106009 Inner wall limited at midplane: High power L-mode (5.3-5.8 MW), no transition 1040106020, 27 (nominal ne), 1040106021,22,23,25,26 (downward ne scan) L-H transitions, 5.2 MW: 1040106018 Limited at inner nose: L-H ramp with transition at 1 MW: 1040106029 |
| Physics Operator Summaries |
| Entered: Jul 7 2004 04:36:48:223PM |
| Author: Robert Granetz |
| Physics operator summary for run 1040106 (Tuesday): Purpose: There are two parts to today's operation: 1) MP 363 H-mode power threshold in various configurations (1/2 day) (today will be inboard limiter configuration) 2) Pre-boronization operation (followed by boronization after the run) Session leader: A. Hubbard Physics operator: R. Granetz Engineers in charge: Summary: We completed both goals of today's operation, and then some. We showed that inner wall limited plasmas have very high power thresholds (nearly 6 MW). Even with 6 MW, H-modes are rare. We used a little bit of extra time to investigate the threshold for a configuration that is limited on the inner divertor nose. These had an H-mode power threshold typical of lower x-point plasmas. Throughout the day, the H/D was very low, around 4%, even with 5-6 MW on many shots. At the end of the day we got in the 1 MA fiducial and several no-gas-puffing shots to unload the walls in preparation for tonight's boronization. The machine ran reasonably well today, particularly considering it was the first run since before the holidays. There were several fizzles, possibly due to prefill pressure issues. But lowering the prefill by a few ms resulted in some strong runaway shots. Toward the end of the day, I made a couple of physop mistakes which decreased the number of pre-boronization shots we could take, but the walls did seem to be unloaded. MDS crashed and hung after the last shot, so we're not sure if we got all of that shot's data. Scorecard: 25 plasmas 6 fizzles 1 duds 2 tests or no-power shot cycles 1 aborted and/or screwed up by computer problems ---------- 35 total ------------------------------------------------------------------------------- Engineering setup for Tuesday, 06 Jan 2004 There are two parts to today's operation: 1) MP 363 H-mode power threshold in various configurations (1/2 day) (today will be limiter configuration) 2) Pre-boronization operation (followed by boronization after the run) Session leader: A. Hubbard Physics operator: R. Granetz ECDC overnight in D2 at 2e-4 Torr, stopping by 07:00. Bake at 60 C overnight as well. Run begins at 09:00 and ends at 17:00. Power systems the same as on 1031125033 (0.8 MA, 5.4 T, limiter discharge) A-coils should be hooked up as on 1031204037 (+Dtop -Dbot -Jtop +Jbot), and the power supply should be enabled. Gas setup: fill B-Top with 6 psi D2 Hybrid enabled (PG4) fill B-side lower with 1 psi Ar Hybrid enabled (PG1) leave B-side upper as is Hybrid DISABLED (PG2) fill C-side with 30 psi D2 Hybrid enabled (PG3) **fill NINJA plenum with 6 psi He enabled ** Enable the following gate valves, assuming no vacuum problems: ECE, VUV, DNB Necessary diagnostics: Edge TS, GPC, HIREX, TCI, Langmuir probes (ASP, FSP, and ISP operated in a Mach-flow mode) Desirable: CXRS, FRCECE, Vis. Brem., Chromex looking at He+1 Doppler flow through toroidal fiber views of inner and outer SOL NINJA operation needs to be coordinated with the session leader. ------------------------------------------------------------------------------- RF Setup: All 4 transmitters in Run On by 08:00. Will need Prf > 3 MW for most shots today. ------------------------------------------------------------------------------- Run Plan: MP 363 (1/2 day): 1. Start with lower single null configuration (load from 1031125008), at threshold RF power level (0.8 MW) to check that it is the same as before, and to get valid "same-day" comparison. Repeat with different power if needed to get H-mode. (2-3 shots) 2. Switch to inner wall limited configuration (1031125033, segment 3). a) Two discharges at power level which gives L-H threshold in LSN (i.e. 0.8-1.0 MW). Document edge Thomson profiles, flows, rotation. b) Power ramp to maximum available (5 MW>) to determine whether an H-mode is achievable. From prior experiments, expect to need at least 4 MW. If yes, document profiles at L-H threshold, as above, and in H-mode. If no, document at highest available RF power to set lower bound on edge Te, rotation etc. c) Run discharges with power just below L-H transition for ~200 ms, followed by higher power to get H-mode phase. Pre-boronization plan: 1) Run the 1 MA fiducial shot (1031204037). We will want to keep the main gate valve closed for 8 minutes after each shot. 2) Run a series of typical shots without gas puffing in order to unload the walls before boronization after the run. We will want to keep the main gate valve closed for 8 minutes after each shot. ------------------------------------------------------------------------------- ECDC was done overnight, as well as a 60 C bake. Hybrid coldstart done by the engineering group; no errors found Loaded PCS segment 1 from shot 1031219001, PCS segment 2 from shot 1031125008 segment 2 (0.8 MA, 5.4 T, SNL) PCS segment 3 from 1031125033 segment 3 (0.8 MA, 5.4 T, inboard limited). ------------------------------------------------------------------------------- Shot 01 -- Test of MDS cycle. No power. (Done very early in the morning.) Shot 02 -- Dud. No EF3's Shot 03 -- Plasma. Good shot, except that the density feedback signal failed, so the density was very, very low. Also there is a problem with the RF data acquisition. SNL, left gap=1.5 cm, right gap=1.5-1.9 cm No H-mode (density too low?). Probably had some power from D-port antenna only. Next shot: repeat so we get RF data and H-mode. We are having a short break to track down the RF DAQ problems, the TCI feedback signal problem, and a few other minor things. Shot 04 -- Fizzle. Next shot: reduce prefill puff by 2 ms (from 20 to 18 ms) Shot 05 -- Plasma. Good shot. Prf=0.75 MW from D only; therefore we only got a marginal H-mode. Next shot: repeat to get RF working better. Shot 06 -- Plasma. Good shot. EDA H-mode. D and J antennas worked well. No power from E-port. Threshold power is normal (0.8-1.0 MW). Next shot: repeat one more time. Shot 07 -- Plasma. Disrupted at t=1.33 s, due to an impurity injection. H-mode threshold was slightly higher (1.2 MW) that previously today. Brian is firing the F probe. Next shot: repeat, no PCS changes Shot 08 -- Fizzle. Lots of carbon light. Post-disruption recovery? Next shot: tweak Btor down by 1% Shot 09 -- Plasma. Good shot. Multiple EDA H-modes. All three RF antennas had power. Next shot: No PCS changes. Turn on inner wall scanning probe. Shot 10 -- Plasma. Good shot. Max Prf=5.0 MW, from all three antennas. EDA H-modes. Next shot: switch to inner wall limiter shot. In order to avoid future physop mistakes, I will transfer segment 3 to segment 2, so all PCS programming will continue to be in segment 2. (Note: the Btor tweak a few shots ago was also done in segment 3.) Inner wall scanning probe will be turned off. Shot 11 -- Plasma. Good shot. Inner wall limited. No H-modes. RF ramped from 0.9 to 4.9 MW (all three antennas). Density was rising a a little late in the flattop. Outer gap=13-14 mm. Next shot: no PCS changes Shot 12 -- Fizzle. No discernible problems with startup. Next shot: no PCS changes. Shot 13 -- Plasma. Good shot. Prf=0.9-5.0 MW. No H-modes. Density still ramps up a little late in the flattop. Next shot: no PCS changes. RF will try to put in 5 MW throughout the discharge, rather than ramping up. Shot 14 -- Plasma. Disrupted at 1.46 s. Prf=4.5 MW steady. No H-modes. The video views shows several large injections coming off the inboard wall between F and G, and one of these caused the disruption. Several tiles on the edge of the TS inboard dump continued to glow after the disruption. Next shot: zero the PG3 gas programming (it wasn't big, but we don't want any at all) Shot 15 -- Plasma. Density feedback screwed up, so there were lots of differences compared to preceding shots. RF pulse has been shortened so that there is less heating of inner wall tiles. Next shot: no PCS changes. Shot 16 -- Fizzle. Next shot: no changes Shot 17 -- Fizzle. Nothing looks wrong with the startup. Next shot: reduce prefill another 2 ms (to 16 ms) Shot 18 -- Plasma. Good shot. Prf=5.2 MW. This one may have had 3 short H-modes! Next shot: repeat, no changes Shot 19 -- Aborted due to IGOR problem. No-power shot cycle. Shot 20 -- Plasma. Good shot. Prf=5.3 MW. The cognoscenti claim that this did not have an H-mode, but it sure looks similar to one. Next shot: reduce nl_04 to 0.7e20 m-2 (from 0.8e20) Shot 21 -- Plasma. Good shot. Target density only decreased by 0.04e20 m-2. This shot is essentially identical to the previous shot. Next shot: reduce nl_04 again, this time to 0.6e20 m-2. Also turn off the NINJA helium puff (which has been going all day for He+1 spectral measurements of edge rotation). Shot 22 -- Plasma. Good shot. More RF power (5.7 MW), with similar results as the previous two shots. The cognoscenti claim this was not an H-mode. Next shot: reduce nl_04 again, this time to 0.5e20 m-2. Shot 23 -- Plasma. Good shot. Prf=5.8 MW. Density is down, but there were lots of hard x-rays. Next shot: no PCS changes, but turn the NINJA helium puff back on. Shot 24 -- Plasma. Short, disruptive, lots of runaways. Terminated at t=0.4 s. Next shot: increase prefill puff by 2 ms Shot 25 -- Plasma. Good shot. Prf=5.8 MW, pulse length=0.3 s. H/D signal is giving zero (it's been very low all day). Hard x-rays are gone. Next shot: increase nl_04 by 0.1e20 m-2 (to 0.5e20 m-2) Shot 26 -- Plasma. Good shot. Prf=5.9 MW, pulse length=0.3 s. Similar to preceding shots. Next shot: reload segment 2 from shot 18 today, which is the one that had the most hints of H-modes. Shot 27 -- Plasma. Lots of runaways. No H-modes. Next shot: try for nearly diverted plasma that is just barely limited on the inner divertor nose. Re-enable segment 3 (which has the SNL plasma from shot 10, segment 2), except move RXL in by 4 cm. Shot 28 -- Plasma. Got the desired plasma limited on the inner divertor nose. Very bizarre shape. Also go H-modes with the RF ramp. Bright ring on the top edge of the inner divertor. Disrupted at t=1.31 s. Next shot: start RF power ramp at lower power. Shot 29 -- Plasma. Another good one with the bizarre shape limited on the inner divertor nose. Good long EDA H-mode. Great RF ramp. Threshold power was 1 MW. End of MP 363 Next shot: load in the 1 MA fiducial, shot 1031216001. Also set the main gate valve to remain closed for 8 minutes after the shot. Shot 30 -- Fizzle. Probably too much gas. Next shot: reduce pre-fill by 2 ms. Hope for no runaways. Shot 31 -- Plasma. Good shot. BUT...it was not the 1 MA fiducial...it was still the configuration limited on the inner divertor nose. I forgot to toggle segment 2 on. Therefore segment 3 was still active. Next shot: turn on segment 2, turn off segment 3. This should be the 1 MA fiducial. Shot 32 -- No-power shot cycle. I forgot to load the PCS tree. Shot 33 -- Plasma. Good 1 MA fiducial shot. Lots of short H-modes. The main gate valve stayed closed. Prf=1-4 MW. Next shot: reduce Ip to 0.8 MA, program in a negative density, and zero the PG3 voltage programming. Keep the gate valve closed after the shot for 8 minutes. Shot 34 -- Plasma. Good shot. 0.8 MA, nl_04(target)=0.35e20 m-2. No runaways. Prf=4 MW, pulse length=0.7 s, very clean pulse. Gate valve stayed closed, as desired. Next shot: repeat, no changes. Shot 35 -- Plasma. Disrupted at t=0.64 s. MDSplus has hung, with some of the data acquired, but some not available. nl_04=0.3e20 m-2, so it looks like the walls have been unloaded. The disruption probably helped to unload the walls. End of run. |
| Session Leader Comments | |||
| Jan 6 2004 09:31:53:430AM | 1040106003 | Amanda Hubbard | Plasma, LSN. But low ne, low RF. Fix and repeat. |
| Jan 6 2004 10:02:13:000AM | 1040106005 | Amanda Hubbard | Plasma, LSN. 780 kA, 5.45 T, nel 8e19 m-2. Lower RF power than requested (D only), Got late L-H at 1.2 secs, 720 kW, about same threshold as 1125. Repeat to improve RF coupling. |
| Jan 6 2004 10:22:58:437AM | 1040106006 | Amanda Hubbard | Plasma, LSN. 780 kA, 5.45 T, nel 8e19 m-2. Still Lower RF power than requested (D and J only), Got earlier L-H at 1.2 secs, ~ 1 MW, Repeat with only D and J in early phase. |
| Jan 6 2004 10:37:22:557AM | 1040106007 | Amanda Hubbard | Plasma, LSN. 780 kA, 5.45 T, nel 8e19 m-2. 850 kW in lower phase. But, no L-H transition until ramp, 1.02 s, 1.32 MW. Note outgassing raised L-mode nel to 9e19m-2. |
| Jan 6 2004 11:02:40:000AM | 1040106009 | Amanda Hubbard | Plasma, LSN. Reduced Bt to 5.41 T (moves GPC in a bit). RF 950 kW flat; got L-H at 0.776 s. But, big injection at 0.71secs means conditions not steady. Repeat one more time. |
| Jan 6 2004 11:18:15:883AM | 1040106010 | Amanda Hubbard | Plasma, LSN. Good clear threshold shot. RF 950 kW flat; got L-H at 0.770 s. Got inner wall scanning probe data. |
| Jan 6 2004 11:34:59:960AM | 1040106011 | Amanda Hubbard | Inner wall limited. Early phase at 880 kW, then RF ramps to 4.8 MW> Stays in L-mode (sorry John). But, there is significant outgassing, nel up to 1.4 e20 m-2. Will repeat this waveform for better scanning probe data, and wall conditioning. Te8 to 400 eV, Te9 to 180 eV |
| Jan 6 2004 11:55:11:507AM | 1040106013 | Amanda Hubbard | Inner wall limited. Early phase at 880 kW, then RF ramps to 5.1 MW Stays in L-mode. Still significant outgassing, nel up to 1.3 e20 m-2. Big injection at 1.4 MW. Next shot, full RF early. |
| Jan 6 2004 12:12:50:163PM | 1040106013 | Amanda Hubbard | Inner wall limited. Good RF at 4.5 MW, steady. Still L-mode. A lot of inner wall heating, injections after 1 second. nel 0.9-1.25e20 m-2 (programmed to be 0.8) Next shot, shorten and delay RF pulse. |
| Jan 6 2004 04:18:44:857PM | 1040106014 | Amanda Hubbard | Limited. Steady 4.5 MW, remains L-mode. Strong outgassing, nel 0.9-1.3 secs, Lots of injections after 1 second. |
| Jan 6 2004 01:07:47:877PM | 1040106015 | Amanda Hubbard | Inner wall limited. Good RF at 5.2 MW, steady. Still L-mode. Due to TCI feedback problems, nel was high resulting in RF trips. Repeat. |
| Jan 6 2004 01:14:03:897PM | 1040106018 | Amanda Hubbard | Inner wall limited. Good RF at 5.24 MW, with trips. Possible brief H-modes at 0.847 s, 0.942 s. RF trips at L-H, so not sustained. Retune and repeat. If confirmed, this may be the first truly inner-wall limited H-modes on C-Mod. RF power threshold 5.2 MW (higher than LSN, DN or UN), Te8 448 eV, Te9 243 eV |
| Jan 6 2004 01:45:38:000PM | 1040106020 | Amanda Hubbard | Inner wall limited. Good RF at 5.3 MW, with trips. Apparently L-mode this time. Nel 0.9-1.3e20 m-2, nebar 1.6-2.2e20m-3. Must be 'on the edge' of threshold. Next shot lower ne. |
| Jan 6 2004 01:56:08:757PM | 1040106021 | Amanda Hubbard | Inner wall limited. Good RF at 5.3 MW, with trips. Apparently L-mode . Nel 0.85-1.2e20 m-2, nebar 1.5-2.2e20m-3. Te8 460 eV Next shot try to lower ne more. |
| Jan 6 2004 02:49:06:700PM | 1040106022 | Amanda Hubbard | Inner wall limited. Good RF at 5.7 MW, . Still L-mode! Nel 0.73-1.07e20 m-2, nebar 1.5-2.1e20m-3. Te8 500 eV Next shot try to lower ne even more. |
| Jan 6 2004 02:51:45:230PM | 1040106023 | Amanda Hubbard | Inner wall limited. Good RF at 5.7 MW, . Still L-mode! Lower, Nel 0.6-0.9e20 m-2, nebar 1.1-21.6e20m-3. Edge starts hot, but cools quickly. High Prad and Zeff; maybe too low in nel. |
| Jan 6 2004 02:52:08:073PM | 1040106024 | Amanda Hubbard | Short, x-rays, disruptive. |
| Jan 6 2004 02:53:28:040PM | 1040106025 | Amanda Hubbard | Similar to 23, rather radiative. Still L-mode. nel 0.6-0.9x10^20 m-2. Zeff 4.5=5.5! |
| Jan 6 2004 04:14:00:573PM | 1040106026 | Amanda Hubbard | Raise nel slightly; nel 0.6 in ohmic target, 0.95e20 m-2 in RF. (Still outgassing a lot). L-mode, 5.8 MW. Zeff, Prad still high. Doesn't appear to be a density window for H-mode here. |
| Jan 6 2004 04:09:54:670PM | 1040106027 | Amanda Hubbard | Reload shot 18, higher ne limited shot that gave brief H-modes. This time it didn't, despite very similar density, and 5.8 MW RF. Radiation was higher; we may have deteriorated the wall conditions. Very strong runaways early! |
| Jan 6 2004 03:41:24:907PM | 1040106028 | Amanda Hubbard | Tried something new; inner gap but limited near inner nose. Ramped RF; went into H-modes very early at lowest level of 2 MW. Clearly more like LSN than limiter, despite very apparent material interaction. |
| Jan 6 2004 03:56:42:700PM | 1040106029 | Amanda Hubbard | Similar shape, limited on inner nose. Clean RF ramp 0.7-4.8 MW. L-H at 1.1 MW, 0.82 secs (similar to LSN threshold). Nice long, steady, EDA H-mode. nel 0.7 e20 m-2 ohmic, 0.96 at L-H, 1.76e20 m-3 in H-mode. Very interesting extra information; need to analyse flows and rotation. |
| Physics Operator Comments | |||
| Jan 5 2004 05:23:33:347PM | Robert Granetz | Engineering setup for Tuesday, 06 Jan 2004 There are two parts to today's operation: 1) MP 363 H-mode power threshold in various configurations (1/2 day) (today will be limiter configuration) 2) Pre-boronization operation (followed by boronization after the run) Session leader: A. Hubbard Physics operator: R. Granetz ECDC overnight in D2 at 2e-4 Torr, stopping by 07:00. Bake at 60 C overnight as well. Run begins at 09:00 and ends at 17:00. Power systems the same as on 1031125033 (0.8 MA, 5.4 T, limiter discharge) A-coils should be hooked up as on 1031204037 (+Dtop -Dbot -Jtop +Jbot), and the power supply should be enabled. Gas setup: fill B-Top with 6 psi D2 Hybrid enabled (PG4) fill B-side lower with 1 psi Ar Hybrid enabled (PG1) leave B-side upper as is Hybrid DISABLED (PG2) fill C-side with 30 psi D2 Hybrid enabled (PG3) **fill NINJA plenum with 6 psi He enabled ** Enable the following gate valves, assuming no vacuum problems: ECE, VUV, DNB Necessary diagnostics: Edge TS, GPC, HIREX, TCI, Langmuir probes (ASP, FSP, and ISP operated in a Mach-flow mode) Desirable: CXRS, FRCECE, Vis. Brem., Chromex looking at He+1 Doppler flow through toroidal fiber views of inner and outer SOL NINJA operation needs to be coordinated with the session leader. ------------------------------------------------------------------------------- RF Setup: All 4 transmitters in Run On by 08:00. Will need Prf > 3 MW for most shots today. ------------------------------------------------------------------------------- Run Plan: MP 363 (1/2 day): 1. Start with lower single null configuration (load from 1031125008), at threshold RF power level (0.8 MW) to check that it is the same as before, and to get valid "same-day" comparison. Repeat with different power if needed to get H-mode. (2-3 shots) 2. Switch to inner wall limited configuration (1031125033, segment 3). a) Two discharges at power level which gives L-H threshold in LSN (i.e. 0.8-1.0 MW). Document edge Thomson profiles, flows, rotation. b) Power ramp to maximum available (5 MW>) to determine whether an H-mode is achievable. From prior experiments, expect to need at least 4 MW. If yes, document profiles at L-H threshold, as above, and in H-mode. If no, document at highest available RF power to set lower bound on edge Te, rotation etc. c) Run discharges with power just below L-H transition for ~200 ms, followed by higher power to get H-mode phase. Pre-boronization plan: 1) Run the 1 MA fiducial shot (1031204037). We will want to keep the main gate valve closed for 8 minutes after each shot. 2) Run a series of typical shots without gas puffing in order to unload the walls before boronization after the run. We will want to keep the main gate valve closed for 8 minutes after each shot. | |
| Jan 6 2004 08:27:59:397AM | Robert Granetz | ECDC was done overnight, as well as a 60 C bake. Hybrid coldstart done by the engineering group; no errors found Loaded PCS segment 1 from shot 1031219001, PCS segment 2 from shot 1031125008 segment 2 (0.8 MA, 5.4 T, SNL) PCS segment 3 from 1031125033 segment 3 (0.8 MA, 5.4 T, inboard limited). | |
| Jan 6 2004 08:29:41:410AM | 1040106001 | Robert Granetz | Shot 01 -- Test of MDS cycle. No power. (Done very early in the morning.) |
| Jan 6 2004 09:03:48:470AM | 1040106002 | Robert Granetz | Shot 02 -- Dud. No EF3's |
| Jan 6 2004 09:28:24:207AM | 1040106003 | Robert Granetz | Shot 03 -- Plasma. Good shot, except that the density feedback signal failed, so the density was very, very low. Also there is a problem with the RF data acquisition. SNL, left gap=1.5 cm, right gap=1.5-1.9 cm No H-mode (density too low?). Probably had some power from D-port antenna only. Next shot: repeat so we get RF data and H-mode. We are having a short break to track down the RF DAQ problems, the TCI feedback signal problem, and a few other minor things. |
| Jan 6 2004 09:42:01:827AM | 1040106004 | Robert Granetz | Shot 04 -- Fizzle. Next shot: reduce prefill puff by 2 ms (from 20 to 18 ms) |
| Jan 6 2004 09:54:04:930AM | 1040106005 | Robert Granetz | Shot 05 -- Plasma. Good shot. Prf=0.75 MW from D only; therefore we only got a marginal H-mode. Next shot: repeat to get RF working better. |
| Jan 6 2004 10:11:10:160AM | 1040106006 | Robert Granetz | Shot 06 -- Plasma. Good shot. EDA H-mode. D and J antennas worked well. No power from E-port. Threshold power is normal (0.8-1.0 MW). Next shot: repeat one more time. |
| Jan 6 2004 10:33:19:790AM | 1040106007 | Robert Granetz | Shot 07 -- Plasma. Disrupted at t=1.33 s, due to an impurity injection. H-mode threshold was slightly higher (1.2 MW) that previously today. Brian is firing the F probe. Next shot: repeat, no PCS changes |
| Jan 6 2004 10:39:31:293AM | 1040106008 | Robert Granetz | Shot 08 -- Fizzle. Lots of carbon light. Post-disruption recovery? Next shot: tweak Btor down by 1% |
| Jan 6 2004 11:05:54:690AM | 1040106009 | Robert Granetz | Shot 09 -- Plasma. Good shot. Multiple EDA H-modes. All three RF antennas had power. Next shot: No PCS changes. Turn on inner wall scanning probe. |
| Jan 6 2004 11:09:56:240AM | 1040106010 | Robert Granetz | Shot 10 -- Plasma. Good shot. Max Prf=5.0 MW, from all three antennas. EDA H-modes. Next shot: switch to inner wall limiter shot. In order to avoid future physop mistakes, I will transfer segment 3 to segment 2, so all PCS programming will continue to be in segment 2. (Note: the Btor tweak a few shots ago was also done in segment 3.) Inner wall scanning probe will be turned off. |
| Jan 6 2004 11:23:00:420AM | 1040106011 | Robert Granetz | Shot 11 -- Plasma. Good shot. Inner wall limited. No H-modes. RF ramped from 0.9 to 4.9 MW (all three antennas). Density was rising a a little late in the flattop. Outer gap=13-14 mm. Next shot: no PCS changes |
| Jan 6 2004 11:36:01:070AM | 1040106012 | Robert Granetz | Shot 12 -- Fizzle. No discernible problems with startup. Next shot: no PCS changes. |
| Jan 6 2004 11:52:55:507AM | 1040106013 | Robert Granetz | Shot 13 -- Plasma. Good shot. Prf=0.9-5.0 MW. No H-modes. Density still ramps up a little late in the flattop. Next shot: no PCS changes. RF will try to put in 5 MW throughout the discharge, rather than ramping up. |
| Jan 6 2004 12:13:45:647PM | 1040106014 | Robert Granetz | Shot 14 -- Plasma. Disrupted at 1.46 s. Prf=4.5 MW steady. No H-modes. The video views shows several large injections coming off the inboard wall between F and G, and one of these caused the disruption. Several tiles on the edge of the TS inboard dump continued to glow after the disruption. Next shot: zero the PG3 gas programming (it wasn't big, but we don't want any at all) |
| Jan 6 2004 12:22:57:857PM | 1040106015 | Robert Granetz | Shot 15 -- Plasma. Density feedback screwed up, so there were lots of differences compared to preceding shots. RF pulse has been shortened so that there is less heating of inner wall tiles. Next shot: no PCS changes. |
| Jan 6 2004 12:35:43:070PM | 1040106016 | Robert Granetz | Shot 16 -- Fizzle. Next shot: no changes |
| Jan 6 2004 12:51:25:630PM | 1040106017 | Robert Granetz | Shot 17 -- Fizzle. Nothing looks wrong with the startup. Next shot: reduce prefill another 2 ms (to 16 ms) |
| Jan 6 2004 01:05:34:310PM | 1040106018 | Robert Granetz | Shot 18 -- Plasma. Good shot. Prf=5.2 MW. This one may have had 3 short H-modes! Next shot: repeat, no changes |
| Jan 6 2004 01:14:03:193PM | 1040106019 | Robert Granetz | Shot 19 -- Aborted due to IGOR problem. No-power shot cycle. |
| Jan 6 2004 01:59:20:930PM | 1040106020 | Robert Granetz | Shot 20 -- Plasma. Good shot. Prf=5.3 MW. The cognoscenti claim that this did not have an H-mode, but it sure looks similar to one. Next shot: reduce nl_04 to 0.7e20 m-2 (from 0.8e20) |
| Jan 6 2004 01:55:45:867PM | 1040106021 | Robert Granetz | Shot 21 -- Plasma. Good shot. Target density only decreased by 0.04e20 m-2. This shot is essentially identical to the previous shot. Next shot: reduce nl_04 again, this time to 0.6e20 m-2. Also turn off the NINJA helium puff (which has been going all day for He+1 spectral measurements of edge rotation). |
| Jan 6 2004 02:02:39:357PM | 1040106022 | Robert Granetz | Shot 22 -- Plasma. Good shot. More RF power (5.7 MW), with similar results as the previous two shots. The cognoscenti claim this was not an H-mode. Next shot: reduce nl_04 again, this time to 0.5e20 m-2. |
| Jan 6 2004 02:25:21:900PM | 1040106023 | Robert Granetz | Shot 23 -- Plasma. Good shot. Prf=5.8 MW. Density is down, but there were lots of hard x-rays. Next shot: no PCS changes, but turn the NINJA helium puff back on. |
| Jan 6 2004 02:35:10:263PM | 1040106024 | Robert Granetz | Shot 24 -- Plasma. Short, disruptive, lots of runaways. Terminated at t=0.4 s. Next shot: increase prefill puff by 2 ms |
| Jan 6 2004 02:47:53:297PM | 1040106025 | Robert Granetz | Shot 25 -- Plasma. Good shot. Prf=5.8 MW, pulse length=0.3 s. H/D signal is giving zero (it's been very low all day). Hard x-rays are gone. Next shot: increase nl_04 by 0.1e20 m-2 (to 0.5e20 m-2) |
| Jan 6 2004 03:02:35:843PM | 1040106026 | Robert Granetz | Shot 26 -- Plasma. Good shot. Prf=5.9 MW, pulse length=0.3 s. Similar to preceding shots. Next shot: reload segment 2 from shot 18 today, which is the one that had the most hints of H-modes. |
| Jan 6 2004 03:28:14:563PM | 1040106027 | Robert Granetz | Shot 27 -- Plasma. Lots of runaways. No H-modes. Next shot: try for nearly diverted plasma that is just barely limited on the inner divertor nose. Re-enable segment 3 (which has the SNL plasma from shot 10, segment 2), except move RXL in by 4 cm. |
| Jan 6 2004 03:36:36:427PM | 1040106028 | Robert Granetz | Shot 28 -- Plasma. Got the desired plasma limited on the inner divertor nose. Very bizarre shape. Also go H-modes with the RF ramp. Bright ring on the top edge of the inner divertor. Disrupted at t=1.31 s. Next shot: start RF power ramp at lower power. |
| Jan 6 2004 03:49:22:163PM | 1040106029 | Robert Granetz | Shot 29 -- Plasma. Another good one with the bizarre shape limited on the inner divertor nose. Good long EDA H-mode. Great RF ramp. Threshold power was 1 MW. End of MP 363 Next shot: load in the 1 MA fiducial, shot 1031216001. Also set the main gate valve to remain closed for 8 minutes after the shot. |
| Jan 6 2004 04:03:00:087PM | 1040106030 | Robert Granetz | Shot 30 -- Fizzle. Probably too much gas. Next shot: reduce pre-fill by 2 ms. Hope for no runaways. |
| Jan 6 2004 04:15:20:633PM | 1040106031 | Robert Granetz | Shot 31 -- Plasma. Good shot. BUT...it was not the 1 MA fiducial...it was still the configuration limited on the inner divertor nose. I forgot to toggle segment 2 on. Therefore segment 3 was still active. Next shot: turn on segment 2, turn off segment 3. This should be the 1 MA fiducial. |
| Jan 6 2004 04:29:26:610PM | 1040106032 | Robert Granetz | Shot 32 -- No-power shot cycle. I forgot to load the PCS tree. |
| Jan 6 2004 04:40:29:330PM | 1040106033 | Robert Granetz | Shot 33 -- Plasma. Good 1 MA fiducial shot. Lots of short H-modes. The main gate valve stayed closed. Prf=1-4 MW. Next shot: reduce Ip to 0.8 MA, program in a negative density, and zero the PG3 voltage programming. Keep the gate valve closed after the shot for 8 minutes. |
| Jan 6 2004 04:56:03:063PM | 1040106034 | Robert Granetz | Shot 34 -- Plasma. Good shot. 0.8 MA, nl_04(target)=0.35e20 m-2. No runaways. Prf=4 MW, pulse length=0.7 s, very clean pulse. Gate valve stayed closed, as desired. Next shot: repeat, no changes. |
| Jan 6 2004 10:38:21:030PM | 1040106035 | Robert Granetz | Shot 35 -- Plasma. Disrupted at t=0.64 s. MDSplus has hung, with some of the data acquired, but some not available. nl_04=0.3e20 m-2, so it looks like the walls have been unloaded. The disruption probably helped to unload the walls. |
| Engineering Operator Comments | ||||
| Shot | Time | Type | Status | Comment |
| 1 | 07:38:17:780AM | Test | Ok | Shot cycle test |
| 2 | 09:00:49:233AM | Plasma | Bad | EF3 power supply did not fire |
| 3 | 09:16:23:840AM | Plasma | Ok | |
| 4 | 09:33:04:447AM | Plasma | Ok | |
| 5 | 09:48:10:800AM | Plasma | Ok | |
| 6 | 10:04:54:923AM | Plasma | Ok | |
| 7 | 10:18:21:073AM | Plasma | Ok | |
| 8 | 10:32:52:303AM | Plasma | Ok | |
| 9 | 10:46:49:643AM | Plasma | Ok | |
| 10 | 11:03:24:513AM | Plasma | Ok | |
| 11 | 11:16:26:870AM | Plasma | Ok | |
| 12 | 11:29:17:720AM | Plasma | Ok | |
| 13 | 11:42:02:433AM | Plasma | Ok | |
| 14 | 11:56:59:620AM | Plasma | Ok | |
| 15 | 12:13:36:943PM | Plasma | Ok | |
| 16 | 12:31:49:693PM | Plasma | Ok | |
| 17 | 12:44:25:890PM | Plasma | Ok | |
| 18 | 12:56:55:227PM | Plasma | Ok | |
| 19 | 01:09:41:423PM | Plasma | Bad | MHD Camac Hung UP |
| 20 | 01:29:03:063PM | Plasma | Ok | |
| 21 | 01:42:18:607PM | Plasma | Ok | |
| 22 | 01:54:53:460PM | Plasma | Ok | |
| 23 | 02:10:33:950PM | Plasma | Ok | |
| 24 | 02:26:29:913PM | Plasma | Ok | |
| 25 | 02:39:12:993PM | Plasma | Ok | |
| 26 | 02:52:16:917PM | Plasma | Ok | |
| 27 | 03:05:06:277PM | Plasma | Ok | |
| 28 | 03:27:37:640PM | Plasma | Ok | |
| 29 | 03:40:13:847PM | Plasma | Ok | |
| 30 | 03:57:23:967PM | Plasma | Ok | |
| 31 | 04:09:55:420PM | Plasma | Ok | |
| 32 | 04:22:34:383PM | Test | Ok | No Power Shot |
| 33 | 04:32:02:390PM | Plasma | Ok | |
| 34 | 04:44:46:607PM | Plasma | Ok | |
| 35 | 04:57:25:530PM | Plasma | Ok | |