| Miniproposals | ||||||||||
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| Operators | |
| Session leader(s): | Joseph Snipes |
| Physics operator(s): | Earl Marmar |
| Engineering operator(s): | Bill Byford,Bill Parkin,Gary Dekow |
| Engineering Operator Run Comment |
| MP#359 Alfven Eigenmode Damping; SL Snipes; PO:Marmar; EO:Dekow/Byford/P |
| Session Leader Plans |
| Physics Operators Plans |
| Session Leader Summaries |
| Entered: Jul 7 2004 03:49:02:523PM |
| Author: Joseph Snipes |
| Run summary for 1040209 TAE Damping vs Elongation: ------------ Run plan: Start with segment 2 parameters from shot 1021003007 but increase the outer gap by 1 or 2 mm to maintain 1.5 cm throughout most of the shot. Then, we will excite the Active MHD antennas with sweeping frequencies between about 200 - 500 kHz over several shots to look for Alfven eigenmode resonances. When we find at least one resonance, we will then sweep around that frequency and begin to vary the elongation shot to shot by 0.1 increments. We will go down to an elongation of at most 1.2 or perhaps 1.1, then increase the elongation to 1.5, 1.6, and perhaps 1.7 while measuring the damping rate of excited Alfven eigenmodes. If the elongation scan goes well, we will then choose a representative elongation where resonances are easily observed and vary the upper and lower triangularity in several steps shot-to-shot over a broad range from near 0 up to perhaps 0.7 while measuring the damping rates of observed AE resonances. Summary: Attempts to run the Active MHD amplifier with frequency sweeping began O.K., though no clear resonances were observed in the first 6 shots. Then, when a higher frequency was attempted, the amplifier failed for two shots. After power cycling the amplifier, the current returned, but had large spikes in certain frequency ranges. So, I decided to operate just outside those ranges at about 410 kHz constant frequency ramping instead the TF as before. As of shot 23, we managed to put in two TF ramps to get two resonances per shot and we scanned the elongation from about 1.2 to 1.7 with steps of 0.1. Fairly clear resonances were observed on almost all shots with constant frequency. Preliminary analysis gave a damping rate of gamma/omega = 2.3 % for one case. Further analysis is required to determine how the damping rate scales with elongation. No attempt to vary the triangularity was made due to lack of time. Shot 2: Active MHD amplifiers turned on with f0 = 600 kHz. Multiple sweeps programmed down to 400 kHz. VCO was turned off by mistake leaving the frequency at 600 kHz straght across. Shot 3: Turned on the VCO and attached the square wave output of the function generator to ACQ16_1:input_04. Shot 4: Got the desired equilibrium and the VCO is working correctly. Searching for the resonance. Shot 6: Reattached lower Active MHD antenna as passive measurement and disconnected the function generator square wave output from channel ACQ16_1:input_04. Shot 7: Set active MHD frequency up to sweep around 500 kHz and the resulting current was so small that no clear signals were visible on the antennas or pickup coils. Shot 8: Returned to sweep around 400 kHz. Still no current. Shot 9: Power cycled the amplifier. Current is now coming out, but with large spikes between 415 and 436 kHz. Shot 10: Try going to the ramping TF waveform from shot 1021003007 and constant frequency around 430 kHz with VCO setting to -3 V. Appears to be a resonance around 1.2 s on BP20_ABK. Shot 11: Change the constant frequency to a VCO setting of -3.2 V. Shot 12: Change the elongation a little higher to 1.38. Shot 16: Outer gap of 3.5 cm appears to be too large. No observed resonance. Shot 17: Disrupted at 0.42 sec. Shot 18: Repeat of shot 11. Good shot reproducible resonance at 1.2 s. Shot 19: Fizzle! Shot 20: No Active MHD data. Shot 21: No Active MHD data. Shot 22: Good shot and data, but no resonance. Perhaps the elongation is too low. Shot 23: Text book example of two resonances as the TF ramps down and then up again at 0.6 and 1.4 s visible on BP05_ABK. Shot 24: Fizzle! Shot 25: Two resonances but not well separated because the TF ramp is not deep enough. Shot 26: Changed TF ramp to go deeper and now the two resonances are clearly separated at 0.6 and 1.05 s. Elongation up to 1.4. Shot 27: Increase elongation again. Got kappa = 1.7 and even diverted at 1.64 s briefly. Two clear resonances again. Shot 28: Decrease elongation. Got kappa = 1.6. Two clear resonances again. Shot 29: Decrease elongation again. Fizzle! Shot 30: Two clear resonances with kappa = 1.5. Shot 31: Fizzle. |
| Physics Operator Summaries |
| Entered: Jul 7 2004 04:36:48:910PM |
| Author: Earl Marmar |
| MP#359 Alfven Eigenmode Damping SL Joe Snipes PO Earl Marmar ECDC over the weekend in D2 at 2e-4 Torr, stopping by 07:00 on Monday morning. Bake at 60 C over the weekend as well. Run begins at 09:00 and ends at 17:00 Power systems the same as on 1040129001 but the A-coils will not be used. 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) RF will not be needed. Gate valve permissives for the usual suspects (ECE, VUV, DNB) assuming no vacuum issues. Run plan: Start with segment 2 parameters from shot 1021003007 but increase the outer gap by 1 or 2 mm to maintain 1.5 cm throughout most of the shot. Then, we will excite the Active MHD antennas with sweeping frequencies between about 200 - 500 kHz over several shots to look for Alfven eigenmode resonances. When we find at least one resonance, we will then sweep around that frequency and begin to vary the elongation shot to shot by 0.1 increments. We will go down to an elongation of at most 1.2 or perhaps 1.1, then increase the elongation to 1.5, 1.6, and perhaps 1.7 while measuring the damping rate of excited Alfven eigenmodes. If the elongation scan goes well, we will then choose a representative elongation where resonances are easily observed and vary the upper and lower triangularity in several steps shot-to-shot over a broad range from near 0 up to perhaps 0.7 while measuring the damping rates of observed AE resonances. __________________________ Results The machine ran well today. We were able to cover a range of elongations (1.2 < kappa < 1.7), primarily using clearin to change the shape, but also tweaking ZXL and ZXU. Note that the outer gap hardly changes with clearin for inner-wall limited (clearin < 0) discharges, when RCUR is kept constant. The segment 1 gas puff was increased shot by shot, and the early segment 2 target nl_04 was also increased, until by shot 11 the gas was almost full on from 30 to 200 msec.There was no obvious effect on ohmic confinement, but early Zeff was lower. As is typical, BR_0 drifted in the + direction, and the offset was changed by -.5 mT to accommodate. Shot 1 was a fiducial-like shot, without RF. There was a late H-mode and then a suspected locked-mode.The A-coils were off. There were 27 plasmas and 4 fizzles. |
| Session Leader Comments | |||
| Feb 9 2004 08:32:51:127AM | Joseph Snipes | Run plan: Start with segment 2 parameters from shot 1021003007 but increase the outer gap by 1 or 2 mm to maintain 1.5 cm throughout most of the shot. Then, we will excite the Active MHD antennas with sweeping frequencies between about 200 - 500 kHz over several shots to look for Alfven eigenmode resonances. When we find at least one resonance, we will then sweep around that frequency and begin to vary the elongation shot to shot by 0.1 increments. We will go down to an elongation of at most 1.2 or perhaps 1.1, then increase the elongation to 1.5, 1.6, and perhaps 1.7 while measuring the damping rate of excited Alfven eigenmodes. If the elongation scan goes well, we will then choose a representative elongation where resonances are easily observed and vary the upper and lower triangularity in several steps shot-to-shot over a broad range from near 0 up to perhaps 0.7 while measuring the damping rates of observed AE resonances. | |
| Feb 9 2004 09:27:51:730AM | 1040209002 | Joseph Snipes | Shot 2: Active MHD amplifiers turned on with f0 = 600 kHz. Multiple sweeps programmed down to 400 kHz. VCO was turned off by mistake leaving the frequency at 600 kHz straght across. |
| Feb 9 2004 09:32:33:417AM | 1040209003 | Joseph Snipes | Shot 3: Turned on the VCO and attached the square wave output of the function generator to ACQ16_1:input_04. |
| Feb 9 2004 09:51:32:620AM | 1040209004 | Joseph Snipes | Shot 4: Got the desired equilibrium and the VCO is working correctly. Searching for the resonance. |
| Feb 9 2004 10:54:33:103AM | 1040209006 | Joseph Snipes | Shot 6: Reattached lower Active MHD antenna as passive measurement and disconnected the function generator square wave output from channel ACQ16_1:input_04. |
| Feb 9 2004 10:58:32:450AM | 1040209007 | Joseph Snipes | Shot 7: Set active MHD frequency up to sweep around 500 kHz and the resulting current was so small that no clear signals were visible on the antennas or pickup coils. |
| Feb 9 2004 11:53:08:840AM | 1040209008 | Joseph Snipes | Shot 8: Returned to sweep around 400 kHz. Still no current. |
| Feb 9 2004 11:53:47:183AM | 1040209009 | Joseph Snipes | Shot 9: Power cycled the amplifier. Current is now coming out, but with large spikes between 415 and 436 kHz. |
| Feb 9 2004 12:07:01:073PM | 1040209010 | Joseph Snipes | Shot 10: Try going to the ramping TF waveform from shot 1021003007 and constant frequency around 430 kHz with VCO setting to -3 V. Appears to be a resonance around 1.2 s on BP20_ABK. |
| Feb 9 2004 12:35:02:810PM | 1040209011 | Joseph Snipes | Shot 11: Change the constant frequency to a VCO setting of -3.2 V. |
| Feb 9 2004 12:37:03:120PM | 1040209012 | Joseph Snipes | Shot 12: Change the elongation a little higher to 1.38. |
| Feb 9 2004 01:48:14:120PM | 1040209016 | Joseph Snipes | Shot 16: Outer gap of 3.5 cm appears to be too large. No observed resonance. |
| Feb 9 2004 01:48:52:247PM | 1040209017 | Joseph Snipes | Shot 17: Disrupted at 0.42 sec. |
| Feb 9 2004 02:14:02:950PM | 1040209018 | Joseph Snipes | Shot 18: Repeat of shot 11. Good shot reproducible resonance at 1.2 s. |
| Feb 9 2004 02:14:13:903PM | 1040209019 | Joseph Snipes | Shot 19: Fizzle! |
| Feb 9 2004 02:51:12:760PM | 1040209020 | Joseph Snipes | Shot 20: No Active MHD data. |
| Feb 9 2004 02:51:20:917PM | 1040209021 | Joseph Snipes | Shot 21: No Active MHD data. |
| Feb 9 2004 03:05:02:150PM | 1040209022 | Joseph Snipes | Shot 22: Good shot and data, but no resonance. Perhaps the elongation is too low. |
| Feb 9 2004 03:16:20:090PM | 1040209023 | Joseph Snipes | Shot 23: Text book example of two resonances as the TF ramps down and then up again at 0.6 and 1.4 s visible on BP05_ABK. |
| Feb 9 2004 03:27:53:857PM | 1040209024 | Joseph Snipes | Shot 24: Fizzle! |
| Feb 9 2004 04:06:32:527PM | 1040209025 | Joseph Snipes | Shot 25: Two resonances but not well separated because the TF ramp is not deep enough. |
| Feb 9 2004 04:07:52:933PM | 1040209026 | Joseph Snipes | Shot 26: Changed TF ramp to go deeper and now the two resonances are clearly separated at 0.6 and 1.05 s. Elongation up to 1.4. |
| Feb 9 2004 04:25:26:247PM | 1040209027 | Joseph Snipes | Shot 27: Increase elongation again. Got kappa = 1.7 and even diverted at 1.64 s briefly. Two clear resonances again. |
| Feb 9 2004 04:31:36:057PM | 1040209028 | Joseph Snipes | Shot 28: Decrease elongation. Got kappa = 1.6. Two clear resonances again. |
| Feb 9 2004 04:36:20:760PM | 1040209029 | Joseph Snipes | Shot 29: Decrease elongation again. Fizzle! |
| Feb 9 2004 05:00:10:760PM | 1040209031 | Joseph Snipes | Shot 30: Two clear resonances with kappa = 1.5. |
| Feb 9 2004 05:01:16:247PM | 1040209031 | Joseph Snipes | Shot 31: Fizzle! |
| Feb 9 2004 05:46:37:237PM | 1040209031 | Joseph Snipes | Summary: Attempts to run the Active MHD amplifier with frequency sweeping began O.K., though no clear resonances were observed in the first 6 shots. Then, when a higher frequency was attempted, the amplifier failed for two shots. After power cycling the amplifier, the current returned, but had large spikes in certain frequency ranges. So, I decided to operate just outside those ranges at about 410 kHz constant frequency ramping instead the TF as before. As of shot 23, we managed to put in two TF ramps to get two resonances per shot and we scanned the elongation from about 1.2 to 1.7 with steps of 0.1. Fairly clear resonances were observed on almost all shots with constant frequency. Preliminary analysis gave a damping rate of gamma/omega = 2.3 % for one case. Further analysis is required to determine how the damping rate scales with elongation. No attempt to vary the triangularity was made due to lack of time. |
| Physics Operator Comments | |||
| Feb 9 2004 09:12:46:603AM | 1040209001 | Earl Marmar | Start with a fiducial-like shot, no RF load from 1040129001 plasma Brief H-Mode, then looks like a locked mode A-coils off some missing bus rogowski signals |
| Feb 9 2004 09:24:04:823AM | 1040209002 | Earl Marmar | load segment 2 from 1021003007 0.73 MA inner wall limited; no tweaks to outer gap fix bolofeed wire (all 0) and Seg 02, V_10 rename to ACOIL_CUR plasma outer gap is a bit larger than requested |
| Feb 9 2004 09:41:06:323AM | 1040209003 | Earl Marmar | tweak rcur (ramping up by 2.5 mm at 1.5 seconds) to decrease outer gap slightly plasma interferometer problem, no pulsed gas, low density (0.7e20) outer gap pretty steady after 0.7 seconds |
| Feb 9 2004 09:48:24:997AM | 1040209004 | Earl Marmar | add extra pulsed gas after 0.025 s Toroidal field to -149 kA straight across plasma outer gap ~ 1.6 cm |
| Feb 9 2004 10:01:41:667AM | 1040209005 | Earl Marmar | no pcs changes plasma some hesitation in startup |
| Feb 9 2004 10:36:07:667AM | 1040209006 | Earl Marmar | decrease prefill puff from 15 msec to 13 msec increase segment 1 puff after 25 msec (to 65. at 100 msec) extra 20 minute delay before shot (EFC breaker problem) plasma startup looks better, CII signal down no effect on density at t=0.1 seconds |
| Feb 9 2004 10:57:48:527AM | 1040209007 | Earl Marmar | increase gas puff again after 25 msec plasma nl04(0.1s) = 4.07e19 |
| Feb 9 2004 11:10:00:603AM | 1040209008 | Earl Marmar | increase gas puff some more between 25 and 100 msec increase nl_04 demand at 100 msec (segment 2) plasma nl04(0.1s) = 4.9e19 no obvious changes in H-factor |
| Feb 9 2004 11:44:58:510AM | 1040209009 | Earl Marmar | increase segment 1 puff some more after 25 msec increase PG3 program voltage in segment 2 delay in the action while Joe and Josh debug cpci data acquisition, Joe and Willy look at amplifier plasma nl04(0.1 s) = 4.96e19 |
| Feb 9 2004 11:55:30:463AM | 1040209010 | Earl Marmar | go back to TF ramp (program from 1021003007) plasma |
| Feb 9 2004 12:41:02:463PM | 1040209012 | Earl Marmar | change elongation increase ZXU by 1.0 cm decrease ZXL by 1.0 cm Plasma kappa increased by ~.08 |
| Feb 9 2004 12:46:07:400PM | 1040209013 | Earl Marmar | decrease ZXU by 3 cm increase ZXL by 3 cm plasma kappa ~ 1.25 |
| Feb 9 2004 01:06:59:963PM | 1040209014 | Earl Marmar | decrease ZXU another 3 cm increase ZXL another 3 cm plasma kappa ~ 1.2, goes diverted around 1.44 seconds |
| Feb 9 2004 01:19:36:277PM | 1040209015 | Earl Marmar | ZXL and ZXU back to settings of shot 13 decrease clearin by 1 cm decrease rcur by 5 mm plasma kappa ~ 1.2 outer gap increased to 2.5 cm |
| Feb 9 2004 01:33:18:183PM | 1040209016 | Earl Marmar | decrease clearin by 2 cm decrease RCUR by 5 mm plasma; disrupt at 1.5 s losing EF2, then vertical control |
| Feb 9 2004 01:44:59:340PM | 1040209017 | Earl Marmar | reload shot 11 decrease clearin by 4 cm decrease rcur by 1 cm plasma ugly short shot, disrupt at 0.44 |
| Feb 9 2004 01:53:56:497PM | 1040209018 | Earl Marmar | reload shot 11 plasma; looks like 11 |
| Feb 9 2004 02:08:18:950PM | 1040209019 | Earl Marmar | reduce clearin 1 cm, no change in rcur fizzle no obvious problem |
| Feb 9 2004 02:51:40:933PM | 1040209020 | Earl Marmar | no pcs changes plasma kappa ~ 1.24 outer gap ~ 1.5 cm |
| Feb 9 2004 02:51:28:667PM | 1040209021 | Earl Marmar | decrease clearin 1 cm plasma kappa ~ 1.18 |
| Feb 9 2004 03:06:34:497PM | 1040209022 | Earl Marmar | no pcs changes plasma |
| Feb 9 2004 03:07:31:027PM | 1040209023 | Earl Marmar | change TF ramp breaking down at -155kA on TF, then ramp to -125kA at 0.95s, back to -155kA at 1.5 s |
| Feb 9 2004 03:28:10:840PM | 1040209024 | Earl Marmar | increase clearin 3 cm decrease ZXL 1 cm increase ZXU 1 cm fizzle |
| Feb 9 2004 03:50:53:760PM | 1040209025 | Earl Marmar | reduce BR_0 offset by 0.5mT (now 0.0000 T) plasma kappa ~ 1.4 |
| Feb 9 2004 04:04:14:557PM | 1040209026 | Earl Marmar | make the TF ramps faster plasma better TF ramps |
| Feb 9 2004 04:05:14:620PM | 1040209027 | Earl Marmar | increase CLEARIN 1.5 cm decrease ZXL 0.5 cm increase ZXU 0.5 cm |
| Feb 9 2004 04:28:02:400PM | 1040209028 | Earl Marmar | lower TF by 3 kA decrease clearin 5 mm plasma kappa ~ 1.6 |
| Feb 9 2004 04:38:37:137PM | 1040209029 | Earl Marmar | decrease clearin another 5 mm fizzle |
| Feb 9 2004 04:59:07:760PM | 1040209030 | Earl Marmar | no pcs changes plasma kappa ~ 1.5 |
| Feb 9 2004 05:01:17:323PM | 1040209031 | Earl Marmar | reload shot 23 take TF trace from 30 fizzle |
| Engineering Operator Comments | ||||
| Shot | Time | Type | Status | Comment |
| 1 | 09:00:15:687AM | Plasma | Ok | |
| 2 | 09:13:49:713AM | Plasma | Ok | |
| 3 | 09:28:06:307AM | Plasma | Ok | |
| 4 | 09:41:49:887AM | Plasma | Ok | |
| 5 | 09:56:35:650AM | Plasma | Ok | |
| 6 | 10:28:58:370AM | Plasma | Ok | |
| 7 | 10:47:40:307AM | Plasma | Ok | |
| 8 | 11:00:28:150AM | Plasma | Ok | |
| 9 | 11:39:55:557AM | Plasma | Ok | |
| 10 | 11:52:55:620AM | Plasma | Ok | |
| 11 | 12:07:57:650PM | Plasma | Ok | |
| 12 | 12:26:24:090PM | Plasma | Ok | |
| 13 | 12:40:44:400PM | Plasma | Ok | |
| 14 | 12:55:53:323PM | Plasma | Ok | |
| 15 | 01:10:24:603PM | Plasma | Ok | |
| 16 | 01:22:49:950PM | Plasma | Ok | |
| 17 | 01:36:53:870PM | Plasma | Ok | |
| 18 | 01:49:38:120PM | Plasma | Ok | |
| 19 | 02:03:20:433PM | Plasma | Ok | |
| 20 | 02:15:48:450PM | Plasma | Ok | |
| 21 | 02:36:28:700PM | Plasma | Ok | |
| 22 | 02:50:44:043PM | Plasma | Ok | |
| 23 | 03:06:21:603PM | Plasma | Ok | |
| 24 | 03:24:40:480PM | Plasma | Ok | |
| 25 | 03:38:20:463PM | Plasma | Ok | |
| 26 | 03:51:02:510PM | Plasma | Ok | |
| 27 | 04:07:21:997PM | Plasma | Ok | |
| 28 | 04:21:08:323PM | Plasma | Ok | |
| 29 | 04:33:57:213PM | Plasma | Ok | |
| 30 | 04:46:21:933PM | Plasma | Ok | |
| 31 | 04:59:05:090PM | Plasma | Ok | |