| Miniproposals | ||||||||||
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| Operators | |
| Session leader(s): | Jim Terry |
| Physics operator(s): | Steve Wolfe |
| Engineering operator(s): | Ed Fitzgerald,Bill Parkin,Gary Dekow |
| Engineering Operator Run Comment |
| MP#281 Imaging of Edge Turbulence PO:Wolf SL:Terry EO:Fitzgerald,Cochran |
| Session Leader Plans |
| Physics Operators Plans |
| Session Leader Summaries |
| Entered: Jul 7 2004 03:49:24:803PM |
| Author: To Be Determined |
| Mini Proposal 281, "Imaging of Edge Turbulence in Alcator C-Mod". PO: S. Wolfe SL: J. Terry This MP will utilize a new diagnostic that images (in 2D) edge emission from an outboard gas puff has recently come on-line A ~6 cm (radial) x 6 cm (poloidal) portion of the outboard plasma edge and SOL is imaged with ~1 mm spatial resolution. Fast snapshots (~1 microsec exposures) are obtained every 16.7 ms. This diagnostic adds to the complement of edge/SOL turbulence diagnostics, which include the scanning probes and the system that images emission from discreet portions of the camera's 2D field onto fast (250 kHz), filtered diodes. The first goal of this proposal is to correlate the fluctuations in I_sat and/or V_f (as measured by the F-port Scanning Probe) with emission fluctuations measured by the fast diodes viewing a volume in the gas puff that is connected along a flux tube with the Langmuir probe volume. This would establish the physical basis for the emission fluctuations (presently believed to be density fluctuations) and would establish a lower limit on the parallel correlation length. The second goal of the proposal is to observe the turbulence, i.e. the RMS fluctuations in Gas Puff Emission, I_sat, V_floating vs R and the 2D spatial structure of the emission, as we scale the following parameters - the ion gyroradius (through B_T), the collisionality (by changing separately both n_e and parallel connection length), and the impurity concentration. The collisionality is thought to be a key parameter, since recent studies by LaBombard [APS 1999] show that the edge diffusivity increases strongly with local collisionality. The approach consists of 5 parts: Part 1. Begin with NL_04=1e20, 0.75MA, Bt=5.3T, with a -50 kA current ramp from .53 s to .97 s to try to establish correlations between FSP and fast diode signals, indicating flux tube mapping between the viewing volume at A-B and the FSP location. Vary starting Ip by 50 kA each shot, repeat until mapping is seen, up to 5 shots. We should be able to see the correct mapping by observing the shadowing of the fast diode emission signal by the FSP insertion. Part 2. Field scan at constant q (>= 3 shots; get at least 2 of the 3 conditions). Maintain constant nl04 = 0.8e20. a) Raise Bt to 6.0T (Itf=170kA), Ip=1MA b) Reduce Bt to 4.3T(Itf=120kA), Ip=.72MA c) Reduce Bt to 2.6 (Itf=72kA) (or lowest practical), Ip=.43MA (or proportional) Part 3. q/connection length scan - scan the current dynamically fronm 1.2 Ma to 0.6 MA at B_t=5.3 T Part 4. Density ramp (up) and current ramp (down) to reach greenwald limit. Similar to shot 1000606014: Nl4->2.1e20, Ip->0.6MA B=5.4T (~5 shots) Part 5. If time remains, return to conditions of mapping determined in step 1, and puff Ar through the FSP burping probe, observe ArII on the 2D camera. RESULTS - Quite a successful run. We accomplished the first four parts of the MP We did not attempt part 5. Part 1 - Shots 4,5,7-10. We observed some influence of the FSP scan on the fast diode signals (which image at the A-B limiter) when the current was between 0.72 and 0.70 MA. Wether or not the fluctuations correlate awaits further analysis. Certainly the emission fluctuations from the three radially adjacent views were correlated and had a noticable phase difference. Part 2 - Shots 11-14, 16. Got data at each of the 3 fields. The 2D images appeared to have larger turbulent structures at the lowest field (2.6 T). Part 3 - Shots 17,18, 26. Good data thruout the current scan. The fast diodes show the normalized RMS fluctuation level peaking at a current of ~0.85 MA. Part 4 - Shots 19-22,24,25. At the density limit, the plasma detached poloidally. Contrary to our previous experience, this poloidal detachment was quite stable lasting ~400ms. The density was 1.2-1.25 times the Greenwald limit. (The best shot for this was 021.) The very high density and stability of the poloidally detached plasma seem to be new. Previously they would disrupt quickly. The possible reason for the change is the fact that outer strike point is slightly ABOVE the divertor nose during the detachment. Unfortunately, with the detachment, it was hard to see the gas puff over the background. The probe, however, saw a strong reduction in fluctuation level during the detachment. Good images of the turbulence up to the time of detachment (when n/n_GW was ~0.75.) A shot by shot account follows: 001 Plasma - but no magnetics Good A-B limiter puff as seen by the fast diodes and the Gas Puff Imaging 2D camera. No probes inserted. 002 Good plasma - Good A-B limiter puff - comes in at 0.6 s saturates the fast diodes. ASP inserted. No FSP Fast diode time window from .5 to 1.025 s. 003 Good plasma - Good A-B limiter puff - comes in at 0.6 s and still saturates the fast diodes until 1.1 s. ASP inserted. in dwell mode (rho~10 mm) No FSP Fast diode time window from .65 to 1.175 s. 004 Good plasma - Good A-B limiter puff - comes in at 0.6 s but saturates the fast diodes until 1.0 s. ASP inserted in dwell mode (rho~10 mm) FSP plunges at .7, .9 and 1.1, when the current was 716 KA, 688 kA, and 672 kA. No shadowing seen on the last plunge. The fast diode time window is from .65 to 1.175 s. 005 Good plasma - Good A-B limiter puff - comes in at 0.6 s but saturates the fast diodes until 0.8 s. ASP inserted in dwell mode (rho~10 mm) FSP plunges at .7, .9 and 1.1, when the current was 715 KA, 687 kA, and 671 kA. EFIT says that we should see something at the A-B limiter for the 715 kA plunge. No shadowing seen on the last two plunges. The fast diode time window is from .65 to 1.175 s. Ninja plenum pressure was 480 Torr. Reduce to 425 Torr for next shot. 006 fizzle 007 Good plasma - Good A-B limiter puff - comes in at 0.6 s ASP inserted in dwell mode (rho~10 mm). FSP plunges at .7, .9 and 1.1, when the current was 715 KA, 687 kA, and 671 kA. EFIT says that we should see something at the A-B limiter for the 715 kA plunge. No shadowing seen on the last two plunges. The fast diode time window is from .65 to 1.175 s. 008 Good plasma - Good A-B limiter puff - comes in at 0.6 s ASP inserted in dwell mode (rho~10 mm). FSP plunges at .7, .9 and 1.1, when the current was 750 kA, 729 kA, and 720 kA. EFIT says that we should see something at the A-B limiter for the second two plunges. Something seen on diode 3 for the last plunge. The fast diode time window is from .65 to 1.175 s. 009 Good plasma - Good A-B limiter puff - comes in at 0.6 s ASP inserted in dwell mode (rho~10 mm). FSP plunges at .7, .9 and 1.1, when the current was 731 kA, 711 kA, and 699 kA. EFIT says that we should see something at the A-B limiter for the second two plunges. Something seen on diodes 2 and 3 for the last two plunges. The fast diode time window is from .65 to 1.175 s. 010 Good plasma - Good A-B limiter puff - comes in at 0.6 s ASP inserted in dwell mode (rho~10 mm). FSP plunges at .7, .9 and 1.1, when the current was 719 kA, 699 kA, and 685 kA. Something seen on diodes 1, 2, and 3 for the second plunge. The fast diode time window is from .68 to .942 s, since I changed digitization rate to 500 kHz, and therefore intentionally missed the third plunge. 011 Good plasma - start of B_t scan - 6.0 T, I_p=1.0 MA. No A-B limiter puff - background shot ASP inserted in dwell mode (rho~10 mm). No FSP plunge. The fast diode time window is from .68 to 1.174 s (I changed digitization rate back to 250 kHz.) 012 Good plasma - repeat 6.0 T, I_p=1.0 MA shot with A-B limiter puff - in at 0.6 s. ASP inserted in dwell mode (rho~10 mm). No FSP plunge. The fast diode time window is from .68 to .942 s with digitization rate back to 500 kHz. Good 2D camera images. 013 Good plasma - lower field at const q - 4.3 T, I_p=.70 MA shot with A-B limiter puff - in at 0.6 s. ASP inserted in dwell mode (rho~10 mm). No FSP plunge. The fast diode time window is from .68 to .942 s with digitization rate back to 500 kHz. Good 2D camera images. 014 Good plasma - again lower the field at const q - 2.7 T, I_p=.42 MA shot with A-B limiter puff - in at 0.6 s. ASP inserted in dwell mode (rho~10 mm). No FSP plunge. The fast diode time window is from .68 to .942 s with digitization rate at 500 kHz. Fast diode time window misses the time when the field is low though. So repeat with later window. Very good 2D camera images with seeming change in structure from from last shot. 015 Disrupted at 0.54 s 016 Good plasma - again lower the field at const q - 2.6 T, I_p=.44 MA shot with A-B limiter puff - in at 0.6 s. ASP inserted in dwell mode (rho~10 mm). No FSP plunge. The fast diode time window is now from 1.0 to 1.62 s with digitization rate at 500 kHz. Very good 2D camera images Qualitatively the fluctuations seem larger and the structures bigger at lower field. 017 Good plasma - Start dynamic q/conection length scan with I_p ramping down from 1.2 (at 0.6 s) to 0.6 MA (at 1.3 s) at B_t=5.3 T. A-B limiter puff - in at 0.6 s. ASP inserted in dwell mode (rho~10 mm). No FSP plunge. The fast diode time window is from .68 to 1.204 s with digitization rate at 250 kHz. Good 2D camera images. Ramp appears to change structure. 018 Good plasma - Repeat of last shot - a dynamic q/conection length scan with I_p ramping down from 1.2 (at 0.6 s) to 0.6 MA (at 1.3 s) at B_t=5.3 T. A-B limiter puff - in at 0.6 s. ASP inserted in dwell mode (rho~10 mm). No FSP plunge. The fast diode time window is from .58 to 1.104 s with digitization rate at 250 kHz. Good 2D camera images. 019 Good plasma - Start density scan with with I_p ramping down slightly from 0.77 (at 0.6 s) to 0.48 MA (at 1.46 s when is disrupted) at B_t=5.3 T. At 1 s a stable poloidal detachment occurred that allowed a density (NL_04=2.4e20), well above the density limit. (I_p goes from .62 at the start of the detachment to .48 at the end). This is 20% higher than the nominal density limit. A-B limiter puff - in at 0.6 s. ASP inserted in dwell mode (rho~10 mm). No FSP plunge. The fast diode time window is from .65 to 1.174 s with digitization rate at 250 kHz. Good 2D camera images, but saturated during detachment. 020 Good plasma - Repeat of last shot, but turn down the camera gate to 0.5 microsec. Also close the diode apertures to F/5.6. Again at 1 s a stable poloidal detachment occurred . The density is 20% higher than the nominal density limit. A-B limiter puff - in at 0.6 s. ASP inserted in dwell mode (rho~10 mm). No FSP plunge. The fast diode time window is from .65 to 1.174 s with digitization rate at 250 kHz. Good 2D camera images. 021 Good plasma - Repeat of last shot, but with no A-B limiter puff. The density is 20-25% higher than the nominal density limit. No A-B limiter puff - background shot. ASP inserted in dwell mode (rho~10 mm). No FSP plunge. The fast diode time window is from .65 to 1.174 s with digitization rate at 250 kHz. Didn't get the 2D camera images on the computer. 022 Good plasma - Attempted repeat of last shot. This time an early injection at .34 s changes things. No apparent poloidal detachment. Nonetheless the density ramps to 10% higher than the nominal density limit. No A-B limiter puff - background shot. ASP inserted in dwell mode (rho~10 mm). No FSP plunge. The fast diode time window is from .65 to 1.174 s with digitization rate at 250 kHz. Didn't get the 2D camera images on the computer. 023 Dud - no TF 024 Good plasma - Attempted to get rid of the poloidal detachment by stopping the current rampdown at 0.6 MA. This did not prevent the detatchment, which still occurred at 1.07 s. The density is at the nominal limit. The detachment is stable until final current rampdown. (It finally disrupts at Ip=.475 MA.) We also increased A-B limiter puff - now 545 Torr. ASP inserted in dwell mode (rho~10 mm). No FSP plunge. The fast diode time window is from .65 to 1.174 s with digitization rate at 250 kHz. Fast diodes don't saturate during detachment. Good 2D camera images. 025 Good plasma - Attempted to get rid of the poloidal detachment by stopping the current rampdown at 0.6 MA. This did not prevent the detatchment, which still occurred at 1.07 s. The density is at the nominal limit. The detachment is stable until final current rampdown. (It finally disrupts at Ip=.475 MA.) No A-B limiter puff - Background shot ASP inserted in dwell mode (rho~10 mm). No FSP plunge. The fast diode time window is from .65 to 1.174 s with digitization rate at 250 kHz. Fast diodes don't saturate during detachment. Good 2D camera images. Images during the detachment are essentially all background. 026 Good plasma - Repeat of shot 1000912018 but with larger Ninja puff - It is a dynamic q/connection length scan with I_p ramping down from 1.2 (at 0.6 s) to 0.6 MA (at 1.3 s) at B_t=5.3 T. Large A-B limiter puff (541 Torr) - in at 0.6 s. ASP inserted in dwell mode (rho~10 mm). No FSP plunge. The fast diode time window is from .58 to 1.104 s with digitization rate at 250 kHz. Good 2D camera images. |
| Physics Operator Summaries |
| Entered: Jul 7 2004 04:37:11:973PM |
| Author: To Be Determined |
| Physics Operator Summary for Tuesday, 1000912 MP#281 Imaging of Edge Turbulence SL: Terry PO: Wolfe EO: Dekow,Fitzgerald,Parkin Engineering Setup ------------------ Boronization overnight, followed by ECDC in He. Power Systems setup as on 1000906023 (note: TF PLC current limit at 175kA) Gas System: Gas setup - fill B-top with 6 psi of D2 Hybrid enabled fill B-side lower with 1 psi of Ar Hybrid enabled fill B-side upper with 35 psi of D2, available for between-shot ECDC, Hybrid DISABLED fill C-side with 30 psi of D2 Hybrid enabled fill J-bottom with 30 psi of D2 Hybrid DISABLED NINJA - D2 in plenum for A-B limiter puffer at 10 psi The following gate valves should be enabled, assuming no vacuum problems: ECE, VUV DNB gate valve will be DISABLED for the beginning of the run; may enable later. ---------------------------------------------- Run Plan --------- This run will immediately follow boronization, so some portion of it will of necessity be a boronization recovery run. However, we will try to run the MP#281 shots from the beginning, rather than fiducial discharges, in the interest of getting as much done on the MP as possible. We may use between-shot ECDC in D2 if it looks like it will help discharge reproducibility; probably won't, but have it ready just in case. DNB may begin pulsing later in the run, once startup is established, if they are interested. No RF, because it may disturb the SOL and because the fast diodes suffer from some RF pickup. At some convenient time during the day, we may try reducing the EF2 resistor from 45mOhm to ~42mOhm, thereby freeing up two stainless steel ballast resistors for possible use in a reverse-current path for the EF2 coils. This test should not be done if it would interfere with the primary experiment. Sequence: 1. Begin with NL_04=1e20, 0.75MA, Bt=5.3T, with a -50 kA current ramp from .53 s to .97 s to try to establish correlations between FSP and fast diode signals, indicating flux tube mapping between the viewing volume at A-B and the FSP location. Vary starting Ip by 50 kA each shot (700,650,800ka), until mapping is seen (up to 5 shots). 2. Field scan at constant q (>= 3 shots; get at least 2 of the 3 conditions). Maintain constant nl04 = 0.8e20. a) Raise Bt to 6.0T (Itf=170kA), Ip=1MA b) Reduce Bt to 4.3T(Itf=120kA), Ip=.72MA c) Reduce Bt to 2.6 (Itf=72kA) (or lowest practical), Ip=.43MA (or proportional) 3. Density ramp (up) and current ramp (down) to reach greenwald limit. Similar to 1000606014: Nl4->2.1e20, Ip->0.6MA B=5.3T (~5 shots) 4. If time remains, return to conditions of mapping determined in step 1, and puff Ar through the FSP burping probe, observe ArII on the 2D camera. Results: -------- We started as planned with the mapping experiment. On the first shot the magnetics CAMAC failed. Bob found that a wire had been disconnected in the magnetics rack, and fixed the problem before shot #2. We then took several shots refining the FSP target and adjusting the NINJA level to avoid saturation of the diode signals. No shadowing was observed at the first current setting, which was supposed to be 750->700kA but was actually somewhat lower current. We then scanned over a range of currents, and reduced the density. It was not immediately clear whether we had found the desired mapping or not. On shots 9 and 10, JT thinks he sees the shadow of the probe in his signals. The cross correlations will be done later. On shot 11-12, we went to 6T, 1MA. The Bt scan at constant q continued with 4.3T on shot 13, 2.6T on 14-16 (15 disrupted.) On shot 17-18, we did a dynamic q/connection length scan, which was part of the MP but had inadvertantly been left out of the run plan. This was a 5.3T shot with Ip ramped down from 1.2MA-0.6MA. Density limit shots were run on shots#19-25 . These were very interesting in that they developed a poloidal detachment (shark-fin) at about 1sec, after which the density rose to a level about 20% above the greenwald limit and lasted 300-400msec before disrupting. With the current held flat at .69MA, the fin lasts into rampdown. Shot #26 re-visited the q-scan of shots 17-18, with a different NINJA puff at the A-B limiter. We did not get to do the Argon puff from the burping probe, which was the lowest priority of the five experiments listed in the MP. We also never got to try the EF2 resistor change; this should be attempted tomorrow, if possible. The machine ran well today, with only one fizzle (#6) and one TF-failure dud (#23); the other 24 plasmas ran successfully, except for one unplanned disruption (#15). Between shot ECDC was not needed, since we were getting reproducible startups. However, the H/D ratio during the lower-density shots was up to 7% or so, which may indicate the boronization was not that good. I suggest that we continue to have the between-shot ECDC available for the next runs. The DNB was enabled and firing into plasma from shot#8-20, and on shot 26; timing was 1.4-1.5sec. They turned off for the later density limit shots because of high gas load from the torus. |
| Session Leader Comments | |||
| Sep 12 2000 05:50:50:590PM | Jim Terry | This is MP 281, "Imaging of Edge Turbulence in Alcator C-Mod". It will utilize a new diagnostic that images (in 2D) edge emission from an outboard gas puff has recently come on-line A ~6 cm (radial) x 6 cm (poloidal) portion of the outboard plasma edge and SOL is imaged with ~1 mm spatial resolution. Fast snapshots (~1 microsec exposures) are obtained every 16.7 ms. This diagnostic adds to the complement of edge/SOL turbulence diagnostics, which include the scanning probes and the system that images emission from discreet portions of the camera's 2D field onto fast (250 kHz), filtered diodes. The first goal of this proposal is to correlate the fluctuations in I_sat and/or V_f (as measured by the F-port Scanning Probe) with emission fluctuations measured by the fast diodes viewing a volume in the gas puff that is connected along a flux tube with the Langmuir probe volume. This would establish the physical basis for the emission fluctuations (presently believed to be density fluctuations) and would establish a lower limit on the parallel correlation length. The second goal of the proposal is to observe the turbulence, i.e. the RMS fluctuations in Emission, I_sat, V_floating vs R and the 2D spatial structure of the emission, as we scale the following parameters - the ion gyroradius (through B_T), the collisionality (by changing separately both n_e and parallel connection length), and the impurity concentration. The collisionality is thought to be a key parameter, since recent studies by LaBombard [APS 1999] show that the edge diffusivity increases strongly with local collisionality. The approach is: Fill the NINJA plenum with 10 PSI D2 for A-B limiter puffs. Part 1. Begin with NL_04=1e20, 0.75MA, Bt=5.3T, with a -50 kA current ramp from .53 s to .97 s to try to establish correlations between FSP and fast diode signals, indicating flux tube mapping between the viewing volume at A-B and the FSP location. Vary starting Ip by 50 kA each shot, repeat until mapping is seen, up to 5 shots. We should be able to see the correct mapping by observing the shadowing of the fast diode emission signal by the FSP insertion. Part 2. Field scan at constant q (>= 3 shots; get at least 2 of the 3 conditions). Maintain constant nl04 = 0.8e20. a) Raise Bt to 6.0T (Itf=170kA), Ip=1MA b) Reduce Bt to 4.3T(Itf=120kA), Ip=.72MA c) Reduce Bt to 2.6 (Itf=72kA) (or lowest practical), Ip=.43MA (or proportional) Part 3. q/connection length scan - scan the current dynamically fronm 1.2 Ma to 0.6 MA at B_t=5.3 T Part 4. Density ramp (up) and current ramp (down) to reach greenwald limit. Similar to 1000606014: Nl4->2.1e20, Ip->0.6MA B=5.4T (~5 shots) Part 5. If time remains, return to conditions of mapping determined in step 1, and puff Ar through the FSP burping probe, observe ArII on the 2D camera. | |
| Sep 12 2000 09:49:53:280AM | 1000912001 | Jim Terry | Plasma - but no magnetics Good A-B limiter puff as seen by the fast diodes and the GPI camera. No probes inserted. |
| Sep 12 2000 09:55:17:997AM | 1000912002 | Jim Terry | Good plasma - Good A-B limiter puff - comes in at 0.6 s saturates the fast diodes. ASP inserted. No FSP Fast diode time window from .5 to 1.025 s. |
| Sep 12 2000 10:09:23:263AM | 1000912003 | Jim Terry | Good plasma - Good A-B limiter puff - comes in at 0.6 s and still saturates the fast diodes until 1.1 s. ASP inserted. in dwell mode (rho~10 mm) No FSP Fast diode time window from .65 to 1.175 s. |
| Sep 12 2000 10:26:27:763AM | 1000912004 | Jim Terry | Good plasma - Good A-B limiter puff - comes in at 0.6 s but saturates the fast diodes until 1.0 s. ASP inserted in dwell mode (rho~10 mm) FSP plunges at .7, .9 and 1.1. No shadowing seen on the last plunge. The fast diode time window is from .65 to 1.175 s. |
| Sep 12 2000 10:40:25:590AM | 1000912005 | Jim Terry | Good plasma - Good A-B limiter puff - comes in at 0.6 s but saturates the fast diodes until 0.8 s. ASP inserted in dwell mode (rho~10 mm) FSP plunges at .7, .9 and 1.1, when the current was 715 KA, 687 kA, and 671 kA. EFIT says that we should see something at the A-B limiter for the 715 kA plunge. No shadowing seen on the last two plunges. The fast diode time window is from .65 to 1.175 s. Ninja plenum pressure was 480 Torr. Reduce to 425 Torr for next shot. |
| Sep 12 2000 10:47:12:247AM | 1000912006 | Jim Terry | fizzle |
| Sep 12 2000 11:17:52:107AM | 1000912007 | Jim Terry | Good plasma - Good A-B limiter puff - comes in at 0.6 s ASP inserted in dwell mode (rho~10 mm). FSP plunges at .7, .9 and 1.1, when the current was 765 KA, 647 kA, and 724 kA. EFIT says that we should see something at the A-B limiter for the second two plunges. No clear shadowing seen . T he fast diode time window is from .65 to 1.175 s. |
| Sep 12 2000 11:29:59:840AM | 1000912007 | Jim Terry | Good plasma - Good A-B limiter puff - comes in at 0.6 s ASP inserted in dwell mode (rho~10 mm). FSP plunges at .7, .9 and 1.1, when the current was 765 KA, 647 kA, and 724 kA. EFIT says that we should see something at the A-B limiter for the second two plunges. No clear shadowing seen. The fast diode time window is from .65 to 1.175 s. |
| Sep 12 2000 11:44:34:810AM | 1000912008 | Jim Terry | Good plasma - Good A-B limiter puff - comes in at 0.6 s ASP inserted in dwell mode (rho~10 mm). FSP plunges at .7, .9 and 1.1, when the current was 750 kA, 729 kA, and 720 kA. EFIT says that we should see something at the A-B limiter for the second two plunges. Something seen on diode 3 for the last plunge. The fast diode time window is from .65 to 1.175 s. |
| Sep 12 2000 11:45:23:700AM | 1000912009 | Jim Terry | Good plasma - Good A-B limiter puff - comes in at 0.6 s ASP inserted in dwell mode (rho~10 mm). FSP plunges at .7, .9 and 1.1, when the current was 731 kA, 711 kA, and 699 kA. EFIT says that we should see something at the A-B limiter for the second two plunges. Something seen on diodes 2 and 3 for the last two plunges. The fast diode time window is from .65 to 1.175 s. |
| Sep 12 2000 12:13:20:200PM | 1000912010 | Jim Terry | Good plasma - Good A-B limiter puff - comes in at 0.6 s ASP inserted in dwell mode (rho~10 mm). FSP plunges at .7, .9 and 1.1, when the current was 719 kA, 699 kA, and 685 kA. Something seen on diodes 1, 2, and 3 for the second plunge. The fast diode time window is from .68 to .942 s, since I changed digitization rate to 500 kHz, and therefore intentionally missed the thrid plunge. |
| Sep 12 2000 12:24:11:013PM | 1000912011 | Jim Terry | Good plasma - now start B_t scan go to 6.0 T, I_p=1.0 MA. No A-B limiter puff - background shot ASP inserted in dwell mode (rho~10 mm). No FSP plunge. The fast diode time window is from .68 to 1.174 s (I changed digitization rate back to 250 kHz.) |
| Sep 12 2000 12:47:42:030PM | 1000912012 | Jim Terry | Good plasma - repeat 6.0 T, I_p=1.0 MA shot with A-B limiter puff - in at 0.6 s. ASP inserted in dwell mode (rho~10 mm). No FSP plunge. The fast diode time window is from .68 to .942 s with digitization rate back to 500 kHz. Good 2D camera images. |
| Sep 12 2000 12:59:44:890PM | 1000912013 | Jim Terry | Good plasma - lower field at const q - 4.3 T, I_p=.70 MA shot with A-B limiter puff - in at 0.6 s. ASP inserted in dwell mode (rho~10 mm). No FSP plunge. The fast diode time window is from .68 to .942 s with digitization rate back to 500 kHz. Good 2D camera images. |
| Sep 12 2000 01:25:10:997PM | 1000912014 | Jim Terry | Good plasma - again lower the field at const q - 2.7 T, I_p=.42 MA shot with A-B limiter puff - in at 0.6 s. ASP inserted in dwell mode (rho~10 mm). No FSP plunge. The fast diode time window is from .68 to .942 s with digitization rate at 500 kHz. Fast diode time window misses the time when the field is low though. So repeat with later window. Very good 2D camera images with seeming change in structure from from last shot. |
| Sep 12 2000 01:41:22:140PM | 1000912015 | Jim Terry | Disrupted at 0.54 s |
| Sep 12 2000 01:56:05:733PM | 1000912016 | Jim Terry | Good plasma - again lower the field at const q - 2.6 T, I_p=.44 MA shot with A-B limiter puff - in at 0.6 s. ASP inserted in dwell mode (rho~10 mm). No FSP plunge. The fast diode time window is now from 1.0 to 1.62 s with digitization rate at 500 kHz. Very good 2D camera images Qualitatively the fluctuations seem larger and the structures bigger at lower field. |
| Sep 12 2000 02:10:59:920PM | 1000912017 | Jim Terry | Good plasma - Start dynamic q/conection length scan with I_p ramping down from 1.2 (at 0.6 s) to 0.6 MA (at 1.3 s) at B_t=5.3 T. A-B limiter puff - in at 0.6 s. ASP inserted in dwell mode (rho~10 mm). No FSP plunge. The fast diode time window is from .68 to 1.204 s with digitization rate at 250 kHz. Good 2D camera images. Ramp appears to change structure. |
| Sep 12 2000 02:25:33:060PM | 1000912018 | Jim Terry | Good plasma - Repeat of last shot - a dynamic q/conection length scan with I_p ramping down from 1.2 (at 0.6 s) to 0.6 MA (at 1.3 s) at B_t=5.3 T. A-B limiter puff - in at 0.6 s. ASP inserted in dwell mode (rho~10 mm). No FSP plunge. The fast diode time window is from .58 to 1.104 s with digitization rate at 250 kHz. Good 2D camera images. |
| Sep 12 2000 04:49:48:890PM | 1000912019 | Jim Terry | Good plasma - Start density scan with with I_p ramping down slightly from 0.77 (at 0.6 s) to 0.48 MA (at 1.46 s when is disrupted) at B_t=5.3 T. At 1 s a stable poloidal detachment occurred that allowed a density (NL_04=2.4e20), well above the density limit. (I_p goes from .62 at the start of the detachment to .48 at the end). This is 20% higher than the nominal density limit. A-B limiter puff - in at 0.6 s. ASP inserted in dwell mode (rho~10 mm). No FSP plunge. The fast diode time window is from .65 to 1.174 s with digitization rate at 250 kHz. Good 2D camera images., but saturated during detachment. |
| Sep 12 2000 04:50:05:950PM | 1000912020 | Jim Terry | Good plasma - Repeat of last shot, but turn down the camera gate to 0.5 microsec. Also close the diode apertures to F/5.6. Again at 1 s a stable poloidal detachment occurred . The density is 20% higher than the nominal density limit. A-B limiter puff - in at 0.6 s. ASP inserted in dwell mode (rho~10 mm). No FSP plunge. The fast diode time window is from .65 to 1.174 s with digitization rate at 250 kHz. Good 2D camera images. |
| Sep 12 2000 04:51:08:543PM | 1000912021 | Jim Terry | Good plasma - Repeat of last shot, but with no A-B limiter puff. The density is 20-25% higher than the nominal density limit. No A-B limiter puff - background shot. ASP inserted in dwell mode (rho~10 mm). No FSP plunge. The fast diode time window is from .65 to 1.174 s with digitization rate at 250 kHz. Didn't get the 2D camera images on the computer. |
| Sep 12 2000 04:51:30:280PM | 1000912022 | Jim Terry | Good plasma - Attempted repeat of last shot. This time an early injection at .34 s changes things. No apparent poloidal detachment. Nonetheless the density ramps to 10% higher than the nominal density limit. No A-B limiter puff - background shot. ASP inserted in dwell mode (rho~10 mm). No FSP plunge. The fast diode time window is from .65 to 1.174 s with digitization rate at 250 kHz. Didn't get the 2D camera images on the computer. |
| Sep 12 2000 04:12:58:200PM | 1000912023 | Jim Terry | Dud - no TF |
| Sep 12 2000 04:52:18:513PM | 1000912024 | Jim Terry | Good plasma - Attempted to get rid of the poloidal detachment by stopping the current rampdown at 0.6 MA. This did not prevent the detatchment, which still occurred at 1.07 s. The density is at the nominal limit. The detachment is stable until final current rampdown. (It finally disrupts at Ip=.475 MA.) We also increased A-B limiter puff - now 545 Torr. ASP inserted in dwell mode (rho~10 mm). No FSP plunge. The fast diode time window is from .65 to 1.174 s with digitization rate at 250 kHz. Fast diodes don't saturate during detachment. Good 2D camera images. |
| Sep 12 2000 04:54:53:060PM | 1000912025 | Jim Terry | Good plasma - Attempted to get rid of the poloidal detachment by stopping the current rampdown at 0.6 MA. This did not prevent the detatchment, which still occurred at 1.07 s. The density is at the nominal limit. The detachment is stable until final current rampdown. (It finally disrupts at Ip=.475 MA.) No A-B limiter puff - Background shot ASP inserted in dwell mode (rho~10 mm). No FSP plunge. The fast diode time window is from .65 to 1.174 s with digitization rate at 250 kHz. Fast diodes don't saturate during detachment. Good 2D camera images. Images during the detachment are essentially all background. |
| Sep 12 2000 05:10:26:687PM | 1000912026 | Jim Terry | Good plasma - Repeat of shot 1000912018 but with larger Ninja puff - It is a dynamic q/connection length scan with I_p ramping down from 1.2 (at 0.6 s) to 0.6 MA (at 1.3 s) at B_t=5.3 T. Large A-B limiter puff (541 Torr) - in at 0.6 s. ASP inserted in dwell mode (rho~10 mm). No FSP plunge. The fast diode time window is from .58 to 1.104 s with digitization rate at 250 kHz. Good 2D camera images. |
| Physics Operator Comments | |||
| Sep 12 2000 07:51:59:483AM | Steve Wolfe | Load prepared shot 1000912000 from my directory. This started from a shot from 1000906. Modify startup - IC_EF4 to -1295 pg4 pre-puff to 22msec Segment 2 (on) has 750kA, 5.3T, 1e20, with 50kA decreasing current ramp, as called for in run plan. Segment 3 (off) has density and current ramp for density limit shot. | |
| Sep 12 2000 07:54:15:390AM | Steve Wolfe | coldstart at 07:53 No errors, all matrices respond. | |
| Sep 12 2000 09:23:12:123AM | 1000912001 | Steve Wolfe | shot#1: reload pcs at 8:31, With seg 1 from 1000906007 (before alternator slowdown) and change pg4 and ef4 as above. Note this one has lower oh voltages than 1000906023. plasma, full length. No session leader or probe-meister in sight! Looks like a magnetics camac failure. Run EFIT from PCS data. Have to do it manually, since the Ip trace is not there either, so dispatch doesn't get a shot length in mtime. Bob has to resolder something in the cell. |
| Sep 12 2000 09:42:20:997AM | 1000912002 | Steve Wolfe | shot#2: Granetz has fixed the magnetics trigger problem, we hope No PCS changes. Terry and LaBombard have shown up. A Probe will fire this time. plasma, full length, but looked like an injection on the tv. injection raises the density, drops the current at .65. Next shot, ramp RXL out to try to steady the FSP target. |
| Sep 12 2000 10:04:48:623AM | 1000912003 | Steve Wolfe | shot#3: ramp RXL out by 1cm to try to steady the FSP target. plasma, no injection this time. current is dropping more than asked for, it's quite resistive. nl4 is a bit high. next shot: raise itf from 147 -> 150ka to get 5.30T drop nl4 to .9, kill seg 2 pg3 pre-prog. drop zxl another 5mm (ramp) to improve fsp target. |
| Sep 12 2000 10:16:18:983AM | 1000912004 | Steve Wolfe | shot#4: raise itf from 147 -> 150ka to get 5.30T drop nl4 to .9, kill seg 2 pg3 pre-prog. drop zxl another 5mm (ramp) to improve fsp target. plasma, full length. target better, still pulling away a little. JT adjusted the NINJA puff, density now a bit low early. next shot: No changes, JT was saturated during first plunge |
| Sep 12 2000 10:29:55:500AM | 1000912005 | Steve Wolfe | shot#5: No changes, reducing NINJA again plasma, full length. next shot: increase ip by 50kA. |
| Sep 12 2000 10:40:58:390AM | 1000912006 | Steve Wolfe | shot#6: increase ip, now asking for 800->760 fizzle. next shot: drop gas to 20msec, raise br0 to .001 from .0005 |
| Sep 12 2000 11:03:45:810AM | 1000912007 | Steve Wolfe | shot#7: increased ip, now asking for 800->760 drop gas to 20msec, raise br0 to .001 from .0005 plasma, full length. some hesitation at 45kA level, early bd. next shot: enable DNB gat valve, firing at 1.4-1.5sec reduce nl4 from 9e19->7e19, ip down by 20kA |
| Sep 12 2000 11:20:32:153AM | 1000912008 | Steve Wolfe | shot#8: enable DNB gate valve, firing at 1.4-1.5sec reduce nl4 from 9e19->7e19, ip down by 20kA plasma, full length. burst of vertical inst. ~1.3sec nl4 nice and flat at 8e19. DNB arc'ed down. next shot: drop ip another 20kA. |
| Sep 12 2000 11:39:19:043AM | 1000912009 | Steve Wolfe | shot#9: drop ip another 20kA, 760->720kA plasma, full length. next shot: drop ip another 15kA |
| Sep 12 2000 11:51:39:950AM | 1000912010 | Steve Wolfe | shot#10: drop ip another 15kA, 745kA->705kA plasma, full length. We either got it or we didn't; time to move on. next shot: 6T, 1MA |
| Sep 12 2000 12:11:22:293PM | 1000912011 | Steve Wolfe | shot#11: 6T, 1MA. ASP still on dwell, FSP out. plasma, full length. This shot was a No-NINJA background. Next shot: no changes, NINJA puff back on. |
| Sep 12 2000 12:34:08:497PM | 1000912012 | Steve Wolfe | shot#12: 6T, 1MA. ASP still on dwell, FSP out. plasma, full length. next shot: 4.3T, .72MA |
| Sep 12 2000 12:58:09:077PM | 1000912013 | Steve Wolfe | shot#13: 4.3T (120kA), .72MA; start tf rampdown at .05sec (in seg 1). modify rxl evolution in rampdown, it or something, was giving a vertical thrash plasma, full length. Bt=4.33,Ip=700kA. next shot: 2.6Tesla, .43MA |
| Sep 12 2000 01:21:20:233PM | 1000912014 | Steve Wolfe | shot#14: 2.6Tesla, .43MA plasma, disrupted at 1.74sec, gets down to tf=77kA at 1sec. ip =400kA. next shot: drop itf->69kA, raise ip->480 |
| Sep 12 2000 01:35:47:233PM | 1000912015 | Steve Wolfe | shot#15: drop itf->69kA, raise ip->480, to try to get a little better match on q. disrupted at .53sec, big injection; slight jerk at .5sec gain switch, but it seemed to recover. next shot: delay ip gain switch to .7sec |
| Sep 12 2000 01:48:31:437PM | 1000912016 | Steve Wolfe | shot#16: drop itf->69kA, raise ip->480, to try to get a little better match on q. delay ip gain switch to .7sec plasma, to 1.74sec. Move on to a dynamic q scan. |
| Sep 12 2000 02:00:43:700PM | 1000912017 | Steve Wolfe | shot#17: dynamic q scan, B=5.3T, IP=1.2->0.6MA from .6sec to 1.3sec plasma, full length. early current rise is getting slow. next shot: repeat. |
| Sep 12 2000 02:16:25:967PM | 1000912018 | Steve Wolfe | shot#18: repeat with more gas puff from NINJA plasma, full length. next shot: go to density limit shots |
| Sep 12 2000 02:48:01:653PM | 1000912019 | Steve Wolfe | shot#19: density limit shot in seg 3. Call for 2.2e20 at 0.7 sec, ramp ip down to reach .6MA at 1.2sec ip gain switch back at .5sec, rxl, zxl. disrupted at 1.46sec, sharkfin(?) at 1sec, nl4 reaches 2.3e20 disrupts at 475kA. This would be over the density limit. Thomson sees the same thing, so it's not just the TCI seeing the edge. |
| Sep 12 2000 03:01:49:187PM | 1000912020 | Steve Wolfe | shot#20: Try for a repeat, after some adjustments in the cell. Cut Ar puff back to 20msec; shot I had loaded had 45msec of Ar. Similar, to 1.4sec. Fin at 1 sec. next shot: repeat. |
| Sep 12 2000 03:39:13:687PM | 1000912021 | Steve Wolfe | shot #21: repeat with no A-B puff similar behavior. Zweben data lost. Next shot: repeat again |
| Sep 12 2000 03:46:29:967PM | 1000912022 | Steve Wolfe | shot#22: repeat. No A-B puff again this time. reload shot#10 into seg 2, for use with Ar FSP burp, but don't use it yet (leave seg2 off, seg 3 on) shorter, marfes from very early on. disrupts at 1.35sec, had an injection early, then ramped density up without a fin. next shot: hold current at level of .95sec, try to avoid fin that way. |
| Sep 12 2000 04:05:36:217PM | 1000912023 | Steve Wolfe | shot#23: hold current at .69MA from .95sec, try to avoid fin that way. No TF. Next shot: Let's try that again. |
| Sep 12 2000 04:25:48:747PM | 1000912024 | Steve Wolfe | shot#24: hold current at .69MA from .95sec, try to avoid fin that way. disrupts at 1.59sec, fin at 1.07, density falls afterward, disrupts in rampdown at ~450kA. Next shot: repeat this one more time, without A-B puff, for background. Then we'll redo the q-scan shot. We're punting the Ar puff. |
| Sep 12 2000 04:39:50:607PM | 1000912025 | Steve Wolfe | shot#25: repeat this one more time, without A-B puff, for background. disrupts at 1.6sec, fin at 1.15 next shot: redo the q-scan shot. We're punting the Ar puff. |
| Sep 12 2000 05:21:02:280PM | 1000912026 | Steve Wolfe | shot#26: redo the q-scan shot. Reload seg 2 from shot 18 and turn it on. Re-enable the DNB gate valve. plasma, full length. |
| Engineering Operator Comments | ||||
| Shot | Time | Type | Status | Comment |
| 1 | 08:58:16:107AM | Plasma | Ok | |
| 2 | 09:31:50:090AM | Plasma | Ok | |
| 3 | 09:48:30:327AM | Plasma | Ok | |
| 4 | 10:02:39:107AM | Plasma | Ok | |
| 5 | 10:18:37:577AM | Plasma | Ok | |
| 6 | 10:35:59:420AM | Plasma | Ok | |
| 7 | 10:48:28:687AM | Plasma | Ok | |
| 8 | 11:09:06:217AM | Plasma | Ok | |
| 9 | 11:27:18:280AM | Plasma | Ok | |
| 10 | 11:46:20:857AM | Plasma | Ok | |
| 11 | 12:05:32:123PM | Plasma | Ok | |
| 12 | 12:27:59:483PM | Plasma | Ok | |
| 13 | 12:51:52:060PM | Plasma | Ok | |
| 14 | 01:13:42:717PM | Plasma | Ok | |
| 15 | 01:26:58:640PM | Plasma | Ok | |
| 16 | 01:40:29:217PM | Plasma | Ok | |
| 17 | 01:54:28:997PM | Plasma | Ok | |
| 18 | 02:13:56:043PM | Plasma | Ok | |
| 19 | 02:34:58:437PM | Plasma | Ok | |
| 20 | 02:57:47:187PM | Plasma | Ok | |
| 21 | 03:18:03:187PM | Plasma | Ok | |
| 22 | 03:40:34:280PM | Plasma | Ok | |
| 23 | 04:02:50:157PM | Plasma | Bad | No TF on this shot. No faults |
| 24 | 04:16:41:610PM | Plasma | Ok | |
| 25 | 04:35:48:733PM | Plasma | Ok | |
| 26 | 04:57:06:687PM | Plasma | Ok | |