| Miniproposals | ||||||||||
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| Operators | |
| Session leader(s): | Syunichi Shiraiwa |
| Physics operator(s): | Greg Wallace |
| Engineering operator(s): | Bill Cochran,Andy Pfeiffer,Ed Fitzgerald |
| Engineering Operator Run Comment |
| MP 553: Creation of reversed shear current profile using LH on low Ip pl |
| Session Leader Plans |
| Entered: Nov 18 2010 11:35:34:677PM |
| Author: |
| This run is an attempt to produce more deeply reversed profile (eventually current hole) by changing N// and Ip. The idea is to increase N// to move the power deposition outward, and in order to compensation the reduction of total LH driven current, reduce the plasma current accordingly.
Dial up 1101104023 (Ip 470kA, USN, Cryo-pump). The density will be kept as same as possible. A higher density reduce the LHCD, while a lower density increase the risk of mode locking. The MSE pitch angle from the R = 73.5cm (the next to the inner most channel) will be important signal to monitor. HXR profile will be measured for the power deposition profile. However, to achieve stable coupling at a low plasma current with (eventually) mixed phasing is challenging. 1) 90 deg. Phasing + plasma current (500kA, 400kA, 300kA, 250kA?) 2) 120 deg. Phasing + plasma current (500kA, 400kA, 300kA, 250kA?) 3) 75 deg. (right half of LH2) + 120 deg. (right half of LH2) mixed phasing. + plasma current (500kA, 400kA, 300kA, 250kA?) 4) 90 deg. (right half of LH2) + 120 deg. (right half of LH2) mixed phasing. + plasma current (500kA, 400kA, 300kA) 5) 140 deg. 6) 75 deg. (right half of LH2) + 140 deg. (right half of LH2) mixed phasing. + plasma current (500kA, 400kA, 300kA) 7) 90 deg. (right half of LH2) + 140 deg. (right half of LH2) mixed phasing. + plasma current (500kA, 400kA, 300kA) To minimize the OH driven plasma at the center, it is important to do this run under a fully non-inductive condition. Assuming each step takes 2-3 discharges , the step 1-3 will need at least a half day. Depending on the progress of the run and DNB condition, we will either continue to step 4-7 or switch to the other mini-proposal (G. Wallace, Density Limit MP). >>>>>>>>>>>>>>>>> Engineering request for LH <<<<<<<<<<<<<<<<<<<<< LH Launcher position with repect to the limiters: -0.1 mm LH Start time: 0.9 sec LH Stop time: 1.4 sec Phasing: 90 deg (n|| -> deg phasing) 1.6->75, 1.9->90, 2.3->110, 2.7->135, 3.1->147 Net Power desired: 1 MW (For the first shot, pl. set 150kW for each klystron) LH Run Duration: Full day Waveform description: Standard |
| Entered: Nov 18 2010 11:35:35:667PM |
| Author: Syunichi Shiraiwa |
| This run is an attempt to produce more deeply reversed profile (eventually current hole) by changing N// and Ip. The idea is to increase N// to move the power deposition outward, and in order to compensation the reduction of total LH driven current, reduce the plasma current accordingly.
Dial up 1101104023 (Ip 470kA, USN, Cryo-pump). The density will be kept as same as possible. A higher density reduce the LHCD, while a lower density increase the risk of mode locking. The MSE pitch angle from the R = 73.5cm (the next to the inner most channel) will be important signal to monitor. HXR profile will be measured for the power deposition profile. However, to achieve stable coupling at a low plasma current with (eventually) mixed phasing is challenging. 1) 90 deg. Phasing + plasma current (500kA, 400kA, 300kA, 250kA?) 2) 120 deg. Phasing + plasma current (500kA, 400kA, 300kA, 250kA?) 3) 75 deg. (right half of LH2) + 120 deg. (right half of LH2) mixed phasing. + plasma current (500kA, 400kA, 300kA, 250kA?) 4) 90 deg. (right half of LH2) + 120 deg. (right half of LH2) mixed phasing. + plasma current (500kA, 400kA, 300kA) 5) 140 deg. 6) 75 deg. (right half of LH2) + 140 deg. (right half of LH2) mixed phasing. + plasma current (500kA, 400kA, 300kA) 7) 90 deg. (right half of LH2) + 140 deg. (right half of LH2) mixed phasing. + plasma current (500kA, 400kA, 300kA) To minimize the OH driven plasma at the center, it is important to do this run under a fully non-inductive condition. Assuming each step takes 2-3 discharges , the step 1-3 will need at least a half day. Depending on the progress of the run and DNB condition, we will either continue to step 4-7 or switch to the other mini-proposal (G. Wallace, Density Limit MP). >>>>>>>>>>>>>>>>> Engineering request for LH <<<<<<<<<<<<<<<<<<<<< LH Launcher position with repect to the limiters: -0.1 mm LH Start time: 0.9 sec LH Stop time: 1.4 sec Phasing: 90 deg (n|| -> deg phasing) 1.6->75, 1.9->90, 2.3->110, 2.7->135, 3.1->147 Net Power desired: 1 MW (For the first shot, pl. set 150kW for each klystron) LH Run Duration: Full day Waveform description: Standard |
| Physics Operators Plans |
| Entered: Nov 19 2010 08:07:43:990AM |
| Author: Greg Wallace |
| Physop run plan for 1101119
PO: G. Wallace SL: S. Shiraiwa MP 553: Creation of reversed shear current profile using LH on low Ip plasmas ----------------- Engineering Setup ----------------- Run begins at 09:00 and ends at 17:00 Power systems as on:1101104023 Acoil: +Dtop -Dbot -Jtop +Jbot (standard) Hybrid Enabled Gas setup: Fill B-Top with 6 psi D2 Hybrid enabled (PG4) fill B-side lower with 1 psi Ar 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 Enable gate-valves and shutters: ECE, VUV, HiREX Sr, Xeus Leave z-bolo shutter as is (should be open) Torvac gatevalve toggle (yes/no): no Boronization(yes/no): no Overnight ECDC (yes/no): yes ICRF(yes/no): no LH(yes/no): yes Cryopump (yes/no): yes DNB (yes/no): yes Vessel temperature: 35/35/35 ------------------------------ ECDC Parameters (if requested) ------------------------------ gas and pressure: D2 at 2e-4 Torr sweep: 44/45/103 cm scan: 20/120 s ------------------------------ Run plan ------------------------------ Start with 1101104023. Use maximum LH power at 90, 120, 140 deg phasing. Also "compound spectrum" 75+120 deg phasing. May need to reduce Ip as low as 350 kA to get non-inductive operation at high phasing. |
| Session Leader Summaries |
| Entered: Nov 20 2010 10:23:42:397PM |
| Author: |
| Today, we tried to produce a deeply shear profile plasma, as a first step toward current hole.
We increased N// in order to move the LH power deposition (and driven current) more off-axis, and in order to compensate the reduction of total LHCD current, we operate at a rather low plasma current. To take the discharge set to study the effect compound spectrum, which was an idea presented at APS 2008, was also part of this run plan. We started from 90 deg. phasing and reduced the plasma current to make loop voltage close to zero (starting from shot 3, 7, 16). We obtained several successful discharges without locked mode, and these discharges shows following features 1) bifurcation 2) steep electron temperature gradient around r/a = 0.2 3) take a longer time for sawtooth re-appearance after LHCD 4) some discharges show mini-collapse and the mode number of the pre-courser seems to be 2. These observations suggest that the shear profile is more deeply/widely reversed compared to the previous 75 deg. phasing discharges, resulting in the electron ITB formation. As for the long-term goal, although operating at 300kA level was expected to be challenging, we are able to make full length pulse after a few trial and error. (Shot ..) A data set for the compound spectrum was obtained at this current, though its effectiveness appears not so promising at this moment. (Shot ...) It is partly because that the spectrum we tried today is not so clean, and the density rise at LH turn-on, which tended to became more significant at lower current, makes data analysis complicated. Over-all, it was a successful day. The machine was operated smoothly, including LHCD, DNB, and so on, and the experimental data suggests that we obtained a reversed shear eITB discharge using LHCD. |
| Entered: Nov 20 2010 10:42:10:833PM |
| Author: |
| Today, we tried to produce a deeply shear profile plasma, as a first step toward current hole.
We increased N// in order to move the LH power deposition (and driven current) more off-axis, and in order to compensate the reduction of total LHCD current, we operate at a rather low plasma current. To take the discharge set to study the effect compound spectrum, which was an idea presented at APS 2008, was also part of this run plan. We started from 90 deg. phasing and reduced the plasma current to make loop voltage close to zero (starting from shot 3, 7, 16). We obtained several successful discharges without locked mode, and these discharges shows following features 1) bifurcation to electron ITB 2) steep electron temperature gradient around r/a = 0.2 3) take a longer time for sawtooth re-appearance after LHCD 4) some discharges show mini-collapse and the mode number of the pre-courser seems to be 2. As for the long-term goal, although operating at 300kA level was expected to be challenging, we are able to make full length pulse after a few trial and error. (Shot ..) A data set for the compound spectrum was obtained at this current, though its effectiveness appears not so promising at this moment. (Shot ...) It is partly because that the spectrum we tried today is not so clean, and the density rise at LH turn-on, which tended to became more significant at lower current, makes data analysis complicated. Over-all, it was a successful day. The machine was operated smoothly, including LHCD, DNB, and so on, and the experimental data suggests that we obtained eITB discharge using LHCD. |
| Entered: Nov 21 2010 02:50:52:563PM |
| Author: Syunichi Shiraiwa |
| Today, we tried to produce a deeply shear profile plasma, as a first step toward current hole.
We increased N// in order to move the LH power deposition (and driven current) more off-axis, and in order to compensate the reduction of total LHCD current, we operate at a rather low plasma current. To take the discharge set to study the effect compound spectrum, which was an idea presented at APS 2008, was also part of this run plan. We started from 90 deg. phasing and reduced the plasma current to make loop voltage close to zero (starting from shot 3, 7, 16). We obtained several successful discharges without locked mode, and these discharges shows following features 1) bifurcation to eITB 2) steep electron temperature gradient around r/a = 0.2 3) take a longer time for sawtooth re-appearance after LHCD 4) some discharges show mini-collapse and the mode number of the pre-courser seems to be m=2. As for the long-term goal, although operating at 300kA level was expected to be challenging, we are able to make full length pulse after a few trial and error. (Shot ..) A data set for the compound spectrum was obtained at this current, though its effectiveness appears not so promising at this moment. (Shot ...) It is partly because that the spectrum we tried today is not so clean, and the density rise at LH turn-on, which tended to became more significant at lower current, makes data analysis complicated. Over-all, it was a successful day. The machine was operated smoothly, including LHCD, DNB, and so on, and the experimental data suggests that we obtained a "possibly reversed shear" eITB discharge using LHCD. |
| Physics Operator Summaries |
| Entered: Nov 19 2010 05:13:25:740PM |
| Author: Greg Wallace |
| SL Summary for 1101119
The goal of today's run was to attempt to create current hole discharges using LHCD during the flattop. This involved reducing the plasma current as much as possible (down to ~300 kA) while increasing launched n|| of the LH. Ultimately there were many many locked modes, especially after the first few shots. We were also only moderately successful at preventing overshoot of the plasma current at the end of segment 1. The OH1 and OH2 crowbar timing was moved forward from .12 to .08 and finally .07 s to prevent overshoot, but this only helped a bit. Also tried enabling feedback on Ip in seg 1 but again only moderate success. We were able to keep the current to around 450 kA at the max, but could not stop the overshoot entirely. Also ran into problems with OH crossover during the LH pulse. By moving the LH pulse timing we were able to avoid crossover during the Vloop=0 part of the pulse. (dI/dt = 0 and I = 0 simultaneously seems to be a problem.) Scorecard: 26 Plasmas to rampdown 6 Disruptions 0 Fizzles 0 Duds |
| Session Leader Comments | |||
| Nov 19 2010 09:19:42:700AM | 1101119001 | Syunichi Shiraiwa | Run well.
LH : 90 deg. phasing 25% ref. no trip. Density is slightly higher than the reference. Vloop is about 0.2 V at the end of LH pulse. Next: Increase LH power to 160kW for each and decrease the density slightly |
| Nov 19 2010 09:36:19:117AM | 1101119002 | Syunichi Shiraiwa | Run well.
LH : 90 deg. phasing 25% ref. no trip. Density is now as requested. Locked mode at 1.16s Vloop is about 0 V before the locked mode. Next: Decrease Ip to 400kA |
| Nov 19 2010 09:48:42:100AM | 1101119003 | Syunichi Shiraiwa | Run well.
LH : 90 deg. phasing 25% ref. no trip. No Locked mode, Vloop is about 0 V, not yet recharging.... Sawtooth re-starts 1.45s (1.43s in 75 deg. 1101104023) Next: Increase LH power to 170kW |
| Nov 19 2010 09:50:15:583AM | 1101119003 | Syunichi Shiraiwa | Run well.
LH : 90 deg. phasing 25% ref. no trip. No Locked mode, Vloop is about 0 V, not yet recharging.... Sawtooth re-starts 1.45s (1.43s in 75 deg. 1101104023) Next: Increase LH power to 170kW, Ip feedback control during segment 1 to eliminate the overshoot in Ip. |
| Nov 19 2010 09:59:57:013AM | 1101119004 | Syunichi Shiraiwa | Run well.
LH : 90 deg. phasing 25% ref. no trip. Locked mode at 1.3s Sawtooth re-starts 1.42s Next: Increase LH power to 180kW, Ip feedback control during segment 1 to eliminate the overshoot in Ip. |
| Nov 19 2010 10:08:14:920AM | 1101119005 | Syunichi Shiraiwa | Run well.
Locked before LH Next: Increase density request from 2.7 to 3.0e19 |
| Nov 19 2010 10:37:51:930AM | 1101119006 | Syunichi Shiraiwa | Run well.
ITB? start at 1.2 s and collapsed before LH turn-off. Not exactly zero loop voltage. Next: Repeat |
| Nov 19 2010 10:46:40:973AM | 1101119007 | Syunichi Shiraiwa | Run well.
ITB? start at 1.2 s and Te0 ~4.5keV. Several mini-collapse and full-collapse at 1.38s Not exactly zero loop voltage. Next: Increase outer gap by 5mm, Reduce the density program to 2.9 from 3.0 |
| Nov 19 2010 11:00:34:750AM | 1101119008 | Syunichi Shiraiwa | Run well.
Locked? Not exactly zero loop voltage. Next: Next 110 deg phasing. Density control 3.0e19 |
| Nov 19 2010 11:01:17:557AM | 1101119008 | Syunichi Shiraiwa | Run well.
Locked? Not exactly zero loop voltage. Next: Next 110 deg phasing. Density control 3.0e19 Moving on Step two (but 110 deg instead of 120 deg) |
| Nov 19 2010 11:38:42:773AM | 1101119009 | Syunichi Shiraiwa | Run well.
Instability starts at 1.2 s Vloop ~0.25 V |
| Nov 19 2010 11:19:05:923AM | 1101119010 | Syunichi Shiraiwa | Run well.
Instability starts at 1.2 s Vloop ~0.25 V Next: Next decrease Ip to 350kA |
| Nov 19 2010 11:41:26:463AM | 1101119011 | Syunichi Shiraiwa | Run well.
Instability starts at 1.1 s Vloop ~0.25 V Next : reduce to 300kA |
| Nov 19 2010 11:49:05:307AM | 1101119011 | Syunichi Shiraiwa | Run well.
Instability starts at 1.1 s Vloop ~0.25 V LH stops effectively 1.35 s, and sawtooth re-start at 1.4s Next : reduce to 300kA |
| Nov 19 2010 11:49:33:720AM | 1101119011 | Syunichi Shiraiwa | Run well.
Instability starts at 1.1 s Vloop ~0.25 V Long delay of sawtooth restart ? (LH stops effectively 1.35 s, and sawtooth re-start at 1.4s) Next : reduce to 300kA |
| Nov 19 2010 11:52:09:363AM | 1101119012 | Syunichi Shiraiwa | Early disruption
Next : reduce to 300kA |
| Nov 19 2010 12:03:52:863PM | 1101119012 | Syunichi Shiraiwa | Early disruption
Next : try 300kA again |
| Nov 19 2010 12:39:54:770PM | 1101119013 | Syunichi Shiraiwa | Plasma disrupted 1.0 s
Next : try 300kA again |
| Nov 19 2010 12:39:02:010PM | 1101119014 | Syunichi Shiraiwa | Early disruption
Next : try 300kA again |
| Nov 19 2010 12:51:34:497PM | 1101119015 | Syunichi Shiraiwa | Plasma run well, but LH did not couple well
Next : Re-take shot 7 with MSE |
| Nov 19 2010 12:52:53:197PM | 1101119015 | Syunichi Shiraiwa | Plasma run well, but LH did not couple well
Next : Re-take shot 7 with MSE (reload shot 7 and LH phasing to 90 deg.) |
| Nov 19 2010 01:16:07:970PM | 1101119016 | Syunichi Shiraiwa | Plasma run well
ITB? Collapsed at 1.34s. Clear pre-courser on the central SX Next : Re-take shot 7 with MSE (reload shot 7 and LH phasing to 90 deg.) |
| Nov 19 2010 01:30:14:353PM | 1101119017 | Syunichi Shiraiwa | Plasma run well
Disrupted 1.1s MSE has a problem in the DAQ. We will run 110 deg. phasing (shot 15) while they are working on MSE Next : Reload shot 15. Phasing 110 deg. , Klystron 170kW (reduced by 10kW each) |
| Nov 19 2010 01:41:17:337PM | 1101119018 | Syunichi Shiraiwa | Plasma run well
Density rise during LH, and Vloop did not decrease as we wanted. Next : Repeat |
| Nov 19 2010 01:49:39:327PM | 1101119018 | Syunichi Shiraiwa | Plasma run well
Density rise during LH, and Vloop did not decrease as we wanted. Locked mode Next : Repeat |
| Nov 19 2010 01:54:41:737PM | 1101119019 | Syunichi Shiraiwa | Plasma run well
Locked mode, again Next : Back to 90 deg. |
| Nov 19 2010 02:11:08:613PM | 1101119020 | Syunichi Shiraiwa | Run Well.
Maybe ITB developed, but it locked at 1.14s. DNB OK. Next : 75 deg and 110 deg. mix phasing |
| Nov 19 2010 02:42:19:617PM | 1101119022 | Syunichi Shiraiwa | Run Well.
Maybe ITB developed, but it locked at 1.2s. Shot 22, 21, 20 consists a set of compound spectrum and reference spectrum discharges Glow on GK-limiter at this current may have caused the density increase at LH turn-on. Next : Reload shot 7 to play with ITB. First, we try to take MSE data. Phasing is 90 deg. LH power to 180kW for each |
| Nov 19 2010 02:56:15:767PM | 1101119023 | Syunichi Shiraiwa | Run Well.
Another discharge for MSE. Next : Move LH pulse to 0.8s to avoid having the LH pulse when I_OH is crossing over. |
| Nov 19 2010 03:27:45:770PM | 1101119025 | Syunichi Shiraiwa | Try to ramp down of IP during LH, but disrupted probably due to injection at 0.9s
Next: Slow down the ramp down rate. (400 kA at 0.8s -> 380 kA at 1.4s) |
| Nov 19 2010 03:41:35:153PM | 1101119026 | Syunichi Shiraiwa | Full length pulse
Next: Ip 650 kA for Yuri |
| Nov 19 2010 03:48:54:583PM | 1101119027 | Syunichi Shiraiwa | Injection?
Next: Repeat |
| Nov 19 2010 04:03:20:253PM | 1101119028 | Syunichi Shiraiwa | Full pulse length, but locked mode before LH
Next: 350 kA |
| Nov 19 2010 04:25:31:287PM | 1101119029 | Syunichi Shiraiwa | Full pulse length
Density rise during LH....Seems that we can not reduce the Ip any further.... Next: 500 kA |
| Nov 19 2010 04:57:07:243PM | 1101119031 | Syunichi Shiraiwa | Full pulse length
Next: Reload shot 3 and set LH power to 130kW for each. |
| Physics Operator Comments | |||
| Nov 19 2010 09:16:37:863AM | 1101119001 | Greg Wallace | Changes: Load seg 1 from 1101119034. Load seg 2 from 1101104023.
Result: Plasma to rampdown. Clean LH pulse. Density a bit higher than requested. Vloop about -0.2 V, no sawteeth during LH flat top. Next shot: Enable 50 ms Ar puff on PG1 (0.3-0.35 s). Decrease PG3 puff in seg 2 from 100 ms to 80 ms. Decrease programmed overshoot in NL_04 program. |
| Nov 19 2010 09:33:29:260AM | 1101119002 | Greg Wallace | Changes: Enable 50 ms Ar puff on PG1 (0.3-0.35 s). Decrease PG3 puff in seg 2 from 100 ms to 80 ms. Decrease programmed overshoot in NL_04 program.
Result: Some early runaways. Current turns around at .03 s. Let's try benign neglect. Something happens at 1.15 s that hurts the current drive. Looks like the plasma is locking up? Next shot: Reduce Ip to 400 kA in seg 2 to prevent locked mode and get higher current drive fraction. Keep seg 1 as is and see how it goes. |
| Nov 19 2010 09:46:22:003AM | 1101119003 | Greg Wallace | Changes: Reduce Ip to 400 kA in seg 2 to prevent locked mode and get higher current drive fraction. Keep seg 1 as is and see how it goes.
Result: Plasma to rampdown. Good LH. Nearly zero loop voltage at n||=1.9. Next shot: Put feedback control on Ip in seg 1. Proportional gain of 4 starting at 60 ms. Increase LH power to 170 kW/klystron. |
| Nov 19 2010 09:59:37:127AM | 1101119004 | Greg Wallace | Changes: Put feedback control on Ip in seg 1. Proportional gain of 4 starting at 60 ms. Increase LH power to 170 kW/klystron.
Result: Plasma to rampdown. Zero Vloop for full LH pulse. Still some overshoot on Ip in seg 1, but better than before. Locked mode develops at 1.3 s? Next shot: Increase proportional and derivative gain to 6 in seg 1 starting at 60 ms. Increase LH power to 180 kW/klystron. |
| Nov 19 2010 10:21:34:940AM | 1101119005 | Greg Wallace | Changes: Increase proportional and derivative gain to 6 in seg 1 starting at 60 ms. Increase LH power to 180 kW/klystron.
Result: Bounce in startup. Clean LH and zero Vloop, but Syun'ichi says plasma locked early. Next shot: Increase programmed nl_04 to 3e19 during flattop. Increase PG4 prepuff to 60 ms. Crowbar timing moved from 0.12 s to 0.08 s on OH1 and both OH2. |
| Nov 19 2010 10:34:41:047AM | 1101119006 | Greg Wallace | Changes: Increase programmed nl_04 to 3e19 during flattop.
Increase PG4 prepuff to 60 ms. Crowbar timing moved from 0.12 s to 0.08 s on OH1 and both OH2. Result: Still bouncing on startup. Current still overshoots. Crobar tim of 80 ms is after current has overshot. Good LH shot. Sawteeth go away at 1.0 s, core Te jumps up at 1.2 s. Not quite full current drive. Next shot: Increase seg 1 PG3 spike from 75 to 100 to reduce bounce. Change OH1 and OH2 crowbar times from 0.08s to 0.07s. |
| Nov 19 2010 10:49:08:610AM | 1101119007 | Greg Wallace | Changes: Increase seg 1 PG3 spike from 75 to 100 to reduce bounce.
Change OH1 and OH2 crowbar times from 0.08s to 0.07s. Result: Plasma to rampdown. LH clean. Hot spot on 16B septum. Still bouncing on startup. Next shot: Decrease RCUR by 0.0025 m to alleviate hot spot. Decrease flattop nl_04 program to 2.9e19. Increase seg 1 PG4 puff from 60 to 70 ms. |
| Nov 19 2010 11:00:38:657AM | 1101119008 | Greg Wallace | Changes: Decrease RCUR by 0.0025 m to alleviate hot spot.
Decrease flattop nl_04 program to 2.9e19. Increase seg 1 PG4 puff from 60 to 70 ms. Result: Still bouncing. Hot spot on 16B looks same as before. Next shot: Increase IC_EF4U in seg 1 by +10 A before t=0. (-1300 to -1290 A) Increase phasing to 110 deg (n||=2.3). Increase nl_04 in flattop to 3.0e19. |
| Nov 19 2010 11:15:19:810AM | 1101119009 | Greg Wallace | Changes: Increase IC_EF4U in seg 1 by +10 A before t=0. (-1300 to -1290 A)
Increase phasing to 110 deg (n||=2.3). Increase nl_04 in flattop to 3.0e19. Result: No bounce, but breakdown is a little late. Still watching hot spot on 16B septum. Strange behavior around 1.3 s on Ip and Vloop. Density goes down, |Ip| increases, |Vloop| also increases??? Next shot: Decrease IC_EF4U in seg 1 by -5 A before t=0 to address later breakdown. (-1290 to -1295 A) Decrease flattop Ip to 350 kA in seg 2. Stop Ip ramp at 350 kA in seg 1. |
| Nov 19 2010 11:31:21:597AM | 1101119010 | Greg Wallace | Changes: Decrease IC_EF4U in seg 1 by -5 A before t=0 to address later breakdown. (-1290 to -1295 A)
Decrease flattop Ip to 350 kA in seg 2. Stop Ip ramp at 350 kA in seg 1. Result: Plasma to rampdown. Startup looks OK. Several faults on LH. Doesn't look like ionization on grill, but behavior of reflected power appears to be consistent across all waveguides indicating a problem on the grill face. Not much current drive and funny behavior on ECE (sudden drops of ECE without LH faults.). Next shot: Decrease RCUR by 0.002 m to see if that helps keep LH from tripping. |
| Nov 19 2010 11:48:30:743AM | 1101119011 | Greg Wallace | Changes: Decrease RCUR by 0.002 m to see if that helps keep LH from tripping.
Result: Plasma to rampdown. Several trips late in LH. Next shot: Set feedforward voltage to zero on OH1 and OH2 after 0.5 s. Stop Ip ramp at 300 kA in seg 1. Decrease Ip to 300 kA in seg 2. |
| Nov 19 2010 12:03:24:217PM | 1101119012 | Greg Wallace | Changes: Set feedforward voltage to zero on OH1 and OH2 after 0.5 s.
Stop Ip ramp at 300 kA in seg 1. Decrease Ip to 300 kA in seg 2. Result: Disruption at 0.125 s. Might be due to 300 kA demand in seg 1 and early part of seg 2. Will try ramping back down to 300 kA from 350 kA. Next shot: Ramp to 350 kA during seg 1. Ramp down from 350 kA to 300 kA between .1 and .4 s in seg 2. Program ZCUR ramp from 0.001 m to 0.010 m between 0.1 s and 0.15 s in seg 2. |
| Nov 19 2010 12:24:30:483PM | 1101119013 | Greg Wallace | Changes: Ramp to 350 kA during seg 1.
Ramp down from 350 kA to 300 kA between .1 and .4 s in seg 2. Program ZCUR ramp from 0.001 m to 0.010 m between 0.1 s and 0.15 s in seg 2. Result: Disruption at 1.03 s. Plasma goes inner wall limited before disruption due to vertical instability (N/Ncrit=1.6). Next shot: Bring feedforward on OH1 and OH2 after 0.5 s back as in shot 11. Add integral gain of 2 at 0.5 s on Ip in seg 2. Set Ip to 325 kA in seg 2 flattop. |
| Nov 19 2010 12:44:45:400PM | 1101119014 | Greg Wallace | Changes: Bring feedforward on OH1 and OH2 after 0.5 s back as in shot 11.
Add integral gain of 2 at 0.5 s on Ip in seg 2. Set Ip to 325 kA in seg 2 flattop. Result: Disruption at 0.4s. Vertically unstable. Instability starts in seg 1. Next shot: Decrease Ip proportional gain from 6 to 4 in seg 1. Keep ZCUR at 0 during seg 1. |
| Nov 19 2010 12:56:32:747PM | 1101119015 | Greg Wallace | Changes: Decrease Ip proportional gain from 6 to 4 in seg 1.
Keep ZCUR at 0 during seg 1. Result: Plasma to rampdown. LH started tripping at 1.1 s. Next shot: Reload shot 7 seg 2. Keep seg 1 from shot 15, but ramp Ip to 400 kA in seg 1. Back to shot 7 LH parameters. |
| Nov 19 2010 01:08:56:967PM | 1101119016 | Greg Wallace | Changes: Reload shot 7 seg 2.
Keep seg 1 from shot 15, but ramp Ip to 400 kA in seg 1. Back to shot 7 LH parameters. Result: Good shot! Plasma to rampdown. LH ran clean. Beam had 5 good pulses. Next shot: Decrease nl_04 to 2.8e19 in flattop. |
| Nov 19 2010 01:29:24:910PM | 1101119017 | Greg Wallace | Changes: Decrease nl_04 to 2.8e19 in flattop.
Result: Disruption at 1.25 s. OH2U crowbars at 1.12 s. Next shot: Reload shot 15 seg 2. |
| Nov 19 2010 01:40:53:500PM | 1101119018 | Greg Wallace | Changes: Reload shot 15 seg 2.
Result: Plasma to rampdown. A few trips late in LH pulse at same time as D-row ionization flash. Plasma behavior is funny during LH. Sawteeth go away, come back, go away again... Next shot: No changes. |
| Nov 19 2010 01:52:33:550PM | 1101119019 | Greg Wallace | Changes: No changes.
Result: Plasma to rampdown. Clean LH pulse. Looks like it might lock again at 1.1 s? Next shot: Go to 90 deg phasing to see if locking is caused by high n|| LH. |
| Nov 19 2010 02:09:00:820PM | 1101119020 | Greg Wallace | Changes: Go to 90 deg phasing to see if locking is caused by high n|| LH.
Result: Plasma to rampdown. Clean LH pulse. Sustained loop voltage near zero. Density still bumps up at beginning of LH. Sawteeth disappear then reappear again at about 1.305 s. Next shot: Try compound spectrum. 75+110 deg. |
| Nov 19 2010 02:22:14:900PM | 1101119020 | Greg Wallace | Changes: Try compound spectrum. 75+110 deg.
Result: Plasma to rampdown. Clean LH pulse with compound spectrum. Plasma locks at 1.2 s? Next shot: 90+110 deg compound spectrum. No dpcs changes. |
| Nov 19 2010 02:36:34:543PM | 1101119022 | Greg Wallace | Changes: 90+110 deg compound spectrum. No dpcs changes.
Result: Compound spectrum worked OK. Plasma to rampdown. Next shot: Reload seg 2 from shot 7. LH back to regular 90 deg phasing (n||=1.9). |
| Nov 19 2010 02:53:15:980PM | 1101119023 | Greg Wallace | Changes: Reload seg 2 from shot 7.
LH back to regular 90 deg phasing (n||=1.9). Result: Plasma to rampdown. LH ran clean. Not quite zero loop voltage. Next shot: Change LH timing to .8-1.3 s to avoid zero vloop during OH crossover. |
| Nov 19 2010 03:12:55:800PM | 1101119024 | Greg Wallace | Changes: Change LH timing to .8-1.3 s to avoid zero vloop during OH crossover.
Result: Change in timing kept OH crossover from happening during zero loop voltage. Still not quite zero loop voltage. "Funny" behavior still happening at just after 1.2 s. Next shot: Ramp Ip demand from 400 to 350 kA from .8 to 1.4 s. |
| Nov 19 2010 03:25:48:510PM | 1101119025 | Greg Wallace | Changes: Ramp Ip demand from 400 to 350 kA from .8 to 1.4 s.
Result: Disruption during early part of LH pulse. Possibly caused by injection at 0.9 s? Next shot: Ip ramp during LH now goes to 380 kA. |
| Nov 19 2010 03:42:45:930PM | 1101119026 | Greg Wallace | Changes: Ramp in Ip during LH now goes to 380 kA.
Result: Plasma to rampdown. Still have bad behavior---Te crashes at about 1.0 s and does not recover. One trip at beginning of LH. Next shot: Increase Ip in seg 2 to 650 kA for Yuri to see how rotation scales. |
| Nov 19 2010 03:48:37:487PM | 1101119027 | Greg Wallace | Changes: Increase Ip in seg 2 to 650 kA for Yuri to see how rotation scales.
Result: Disruption at 1.0 s. Injection? Next shot: Same, but better. |
| Nov 19 2010 04:04:44:890PM | 1101119028 | Greg Wallace | Changes: Same, but better.
Result: Plasma to rampdown at 650 kA. LH ran clean. Looks like a locked mode again. Next shot: Set Ip during flattop to 350 kA. |
| Nov 19 2010 04:30:09:870PM | 1101119029 | Greg Wallace | Changes: Set Ip during flattop to 350 kA.
Result: Plasma to rampdown. Many trips in second half of LH pulse. Right gap jumping around a lot and some ionization in front of the grill is causing trips. Sawteeth before and after LH suggest not a locked mode. Next shot: Change Ip in flattop to 500 kA. |
| Nov 19 2010 04:41:38:890PM | 1101119030 | Greg Wallace | Changes: Change Ip in flattop to 500 kA.
Result: Plasma to rampdown. Clean LH Locked mode develops at 1.2 s. Next shot: Set Ip to 300 kA in flattop. Change TF demand current from 150kA to 120 kA at .5 s. |
| Nov 19 2010 04:58:59:427PM | 1101119031 | Greg Wallace | Changes: Set Ip to 300 kA in flattop.
Change TF demand current from 150kA to 120 kA at .5 s. Result: Plasma to rampdown. Many trips on LH after .95 s. Looks like something happening on the grill face. TF ramp works OK but plasma still locks. Next shot: Repeat shot 3. |
| Nov 19 2010 05:00:53:247PM | 1101119031 | Greg Wallace | Changes: Repeat of shot 3
Result: Plasma to rampdown. Clean LH, no ITB. Locked mode at 1.05 s? Last shot of the day. |
| Engineering Operator Comments | ||||
| Shot | Time | Type | Status | Comment |
| 1 | 09:03:14:733AM | Plasma | Ok | |
| 2 | 09:19:10:297AM | Plasma | Ok | |
| 3 | 09:34:04:340AM | Plasma | Ok | |
| 4 | 09:47:14:740AM | Plasma | Ok | |
| 5 | 10:01:08:583AM | Plasma | Ok | |
| 6 | 10:22:11:603AM | Plasma | Ok | |
| 7 | 10:35:16:760AM | Plasma | Ok | |
| 8 | 10:50:01:527AM | Plasma | Ok | |
| 9 | 11:02:57:267AM | Plasma | Ok | |
| 10 | 11:17:41:380AM | Plasma | Ok | |
| 11 | 11:33:13:133AM | Plasma | Ok | |
| 12 | 11:49:33:910AM | Plasma | Ok | |
| 13 | 12:04:07:613PM | Plasma | Ok | |
| 14 | 12:25:29:903PM | Plasma | Ok | |
| 15 | 12:45:50:850PM | Plasma | Ok | |
| 16 | 01:00:47:550PM | Plasma | Ok | |
| 17 | 01:13:25:507PM | Plasma | Bad | OH2L fault |
| 18 | 01:33:34:410PM | Plasma | Ok | |
| 19 | 01:46:00:700PM | Plasma | Ok | |
| 20 | 01:58:31:820PM | Plasma | Ok | |
| 21 | 02:13:46:787PM | Plasma | Ok | |
| 22 | 02:27:58:763PM | Plasma | Ok | |
| 23 | 02:42:43:780PM | Plasma | Ok | |
| 24 | 02:58:55:577PM | Plasma | Ok | |
| 25 | 03:14:09:483PM | Plasma | Ok | |
| 26 | 03:28:24:310PM | Plasma | Ok | |
| 27 | 03:43:08:273PM | Plasma | Ok | |
| 28 | 03:57:22:070PM | Plasma | Ok | |
| 29 | 04:12:38:450PM | Plasma | Ok | |
| 30 | 04:27:22:993PM | Plasma | Ok | |
| 31 | 04:41:58:850PM | Plasma | Ok | |
| 32 | 04:56:57:183PM | Plasma | Ok | |
| System Availability | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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