| Miniproposals | ||||||||||
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| Operators | |
| Session leader(s): | John Goetz |
| Physics operator(s): | Ian Hutchinson |
| Engineering operator(s): | Unknown |
| Engineering Operator Run Comment |
| Continued positioning and feedback control of plasma |
| Session Leader Plans |
| Physics Operators Plans |
| Session Leader Summaries |
| Entered: Jul 7 2004 03:49:07:460PM |
| Author: To Be Determined |
| Summary of 26 May 93 Run Total 27 shots. 13 Plasmas exceeding 50 kA; 12 fizzles; 2 No flash. Vertical offset on plasma height was removed and some of the Br offset. These things contributed to improvement in vertical position. However, the plasma still tended to be a little low. Exception was shot 15 which had an early up and inside crash. The problem that this plasma suffered from was fixed, apparently by removing the 5 height PID feedback spike on B_R that had been put in at commutation. The M matrix addition of OH1 and OH2 in addition to EF3 in the R_curr wire seemed to be a good addition. However, the inherited PID gain of 10 was too high, and may have been close to instability. Shot 24, on which the EF3 current limit was moved out of the way showed some oscillations. The gain was lowered to 1. Shot 26 also was the only shot in which the OH1 commutation was at 50 ms, the same as the OH2 and EF1. The inherited setting for the other shots of the day (40ms) caused a big radial position excursion during the period 40-50ms as a result of big voltage discrepancies between OH1 and the other coils. Fixing this is a big step forward and gave a shot with 270kA nearly flat, which lasted till power supplies switched off. The position was very good at 40-55 ms, and then moved in so that for 100-200 ms it was limited on the inboard wall with R ~ 0.60m and a ~ 0.15 m. Erratic current ramps were experienced throughout the day. There is some indication that the exact time of breakdown influences the subsequent current ramp. No systematic fix has been found. But one sure would be nice! IHH. |
| Physics Operator Summaries |
| Session Leader Comments | |||
| May 26 1993 09:19:14:660AM | John Goetz | Begin with shot 930519029
Voltage programming done on OH to control Vloop. Try and bring Vloop to 2V at 100msec and hold it there OH1 voltage = -100V and OH2 voltages = -25V Vertical position has been set to z = 0. To be done later: adjust M matrix for horizontal position feedback To be done later: gang OH2 (and EF1) to OH1 Base pressure 1.3e-7 -- with cryo closed 3.7e-7 Fill pressure 6e-5 | |
| May 26 1993 10:03:43:800AM | 930526001 | John Goetz | Should have been a repeat of 930525026 until 50msec, but the plasma current
never took off. OH1 demand and bus voltage disagree by a factor of 3 to 4. Change the OH1 demand signal to -25V. |
| May 26 1993 10:17:54:940AM | 930526002 | John Goetz | Toroidal field = 4.9T.
Plasma current = 290kAmps max with a disruption at 85msec. Plasma starts low and continues to move down. Magnetic reconstructions very similar to shots at the end of run 930525 Programming changes made to OH1 did not make it through. Will try again for shot 003. |
| May 26 1993 10:30:07:670AM | 930526002 | John Goetz | Toroidal field = 4.9T.
Plasma current = 30 kAmps. Changes for shot 004: EF3 voltage demand now -1000V from 25 msec on (it was -2000V until 50 msec) Attempt to move the plasma out a little if it forms |
| May 26 1993 10:31:53:040AM | 930526003 | John Goetz | Toroidal field = 4.9T.
Plasma current = 30 kAmps. Changes for shot 004: EF3 voltage demand now -1000V from 25 msec on (it was -2000V until 50 msec) Attempt to move the plasma out a little if it forms |
| May 26 1993 10:56:08:100AM | 930526004 | John Goetz | Toroidal field = 4.9T.
Plasma current = 30 kAmps. Changes for shot 005: OH2 commutation resistor lowered to 20mOhms from 25mOhms to try and compensate for the change in OH1 voltage demand programming changes. (it was -2000V until 50 msec) Proportional gain for Br changed from 0 to 0.5 from 30msec to 2sec |
| May 26 1993 11:34:22:780AM | 930526005 | John Goetz | Toroidal field = 4.9T.
Plasma current = 210 kAmps with flattop from 50 to almost 100 msec. Disruption at 100+ msec. Discharge is inside. Reconstruction says the plasma is small. Interferometer and Z-meter say low density. Changes for shot 006: EF3 voltage demand changed from -3000V to -2000V at 2msec and from -2000V to -1500V at 24msec. These changes are an attempt to get the plasma off the inner wall. |
| May 26 1993 11:51:25:300AM | 930526006 | John Goetz | Toroidal field = 4.9T.
Plasma current = 160 kAmps with flattop from 70 to almost 85 msec. Disruption at 88 msec. Discharge begins outside and moves inside starting at about 50msec. Current ramp is much slower (due to changes in EF3 voltage programming) Changes for shot 007: EF3 voltage demand changed from -2000V to -3000V at 2msec and from -1000V to -500V at 100msec. Voltage demand remains -1500V at 24msec. These changes are an attempt to get the current rise rate back and then still be able to control the horizontal position. |
| May 26 1993 12:14:28:350PM | 930526007 | John Goetz | Toroidal field = 5.0T.
Plasma current = 220 kAmps with flattop from 50 to 75 msec. Current begins to ramp down and then disruption at 88 msec. Discharge begins outside and moves inside but not as quickly as shot 006. Changes for shot 008: OH1 voltage demand changed from -25V to -35V (factor of 4 accounted for) from 50 to 200msec and OH2 voltage demand changed from -25V to -35V from 50 to 200msec. Voltage demand remains -1500V at 24msec. These changes are an attempt to lengthen the flattop and try to hold the plasma outside longer. |
| May 26 1993 12:19:03:530PM | 930526008 | John Goetz | Toroidal field = 5.0T.
Plasma current = 20 kAmps No obvious magnetic troubles. Changes for shot 009: None |
| May 26 1993 12:39:42:900PM | 930526009 | John Goetz | Toroidal field = 5.0T.
Plasma current = 200 kAmps Flattop from 50 to 75 msec. Rampdown until disruption at 230msec. Discharge further in than shot 007 because current ramped up less quickly. Changes for shot 010: Changed voltage demand on OH1 from -35V to -45V (factor of 4 taken into account) from 40 to 200msec in order to get more loop voltage. IC_EF4 changed from 600V to 620V at 1msec in order to get the vertical field closer to zero for an earlier breakdown. |
| May 26 1993 12:57:22:010PM | 930526010 | John Goetz | Toroidal field = 5.0T.
Plasma current = 210 kAmps Rampdown until termination at 270msec. Many disruptions during the rampdown. Discharge still a little low. Changes for shot 011: Changed voltage demand on OH1 from -45V to -50V (factor of 4 taken into account) from 40 to 200msec and OH2 voltage demand changed from -35V to -45V in order to get more loop voltage. IC_EF4 changed from 620 to 640Amps at 1msec in order to get the vertical field closer to zero for an earlier breakdown. |
| May 26 1993 01:04:28:900PM | 930526011 | John Goetz | Toroidal field = 5.0T.
Plasma current = 20 kAmps No discernible difference in Bz between shots 010 and 011. Breakdown is a bit (or so) earlier. Changes for shot 012: None |
| May 26 1993 01:24:19:910PM | 930526012 | John Goetz | Toroidal field = 5.0T.
Plasma current = 200 kAmps No flattop. Disruptions on the rampdown. Termination at 265msec. Current rise not as fast as 010 and it rolls over before the top. Changes for shot 013: Changed the Br(0) demand from 8mT to 5mT |
| May 26 1993 01:32:24:080PM | 930526013 | John Goetz | Toroidal field = 5.0T.
Plasma current = 20 kAmps Br(0) lowered from shot 012. Changes for shot 014: None |
| May 26 1993 01:47:02:150PM | 930526014 | John Goetz | Toroidal field = 5.0T.
Plasma current = 30 kAmps Changes for shot 015: Change EF3 voltage demand from 0V at 0msec to 0V at -1msec and from -3000V at 2msec to -3000V at 1msec in order to fiddle with the current rise and breakdown times. |
| May 26 1993 02:10:37:490PM | 930526015 | John Goetz | Toroidal field = 5.0T.
Plasma current = 80 kAmps Current rise faster. Plasma up and inside. Breakdown is 1 msec earlier than 014. Changes for shot 016: Change proportional gain on Br(0) PID from 5 to 1 from 0 to 50msec to see what happens with the vertical position. |
| May 26 1993 02:26:15:060PM | 930526016 | John Goetz | Toroidal field = 5.0T.
Plasma current = 200 kAmps Current rise 150kA in 44msec No flattop - rampdown starts at 100msec. Termination at 270msec. Disruptions during rampdown. PHA temperature shows a dip during the middle of the shot. Vertical position - a little low. Plasma does not slam inside, actually moves out a bit. Changes for shot 017: None |
| May 26 1993 02:36:31:570PM | 930526017 | John Goetz | Toroidal field = 5.0T.
Plasma current = 30 kAmps Breakdown occurs earlier than on shot 016 Changes for shot 018: Fill pressure from 6e-5 to 4e-5 to see if there is an effect on the avalanche. |
| May 26 1993 03:01:30:830PM | 930526018 | John Goetz | Toroidal field = 5.0T.
Plasma current = 220 kAmps Current rise 150kAmps in 42msec Breakdown at 5.5msec Flattop from 90 to 110 msec Disruptions during rampdown - termination at 270msec Plasma rests on inner wall and then expands in volume later in time Changes for shot 019: RCUR predictor changed from EF3 voltage only to EF3 and OH1, OH2_U, and OH2_l voltages. OH1 voltage is -.01 units and the OH2's are -.002 units. (EF3 is +.1 units) |
| May 26 1993 03:12:53:730PM | 930526019 | John Goetz | Toroidal field = 5.0T.
Plasma current = 0 kAmps Too much Bz (-8mT instead of -5mT on shot 018) Breakdown too late. Changes for shot 020: Forgot the factor of 4 on OH1. Changed OH1 voltage in RCUR predictor from -.01 to -.0025. Changed IC_EF4 from 640 to 660 Amps to try and deal with the vertical field. |
| May 26 1993 03:22:56:080PM | 930526020 | John Goetz | Toroidal field = 5.0T.
Plasma current = 0 kAmps Too much Bz; IC_EF4 changes not taken from after last shot. Changes for shot 021: Changed IC_EF4 from 640 to 700 Amps to try and bring the vertical field closer to zero (approx. -7mT now). Fill pressure changed from 4e-5 to 6e-5. |
| May 26 1993 03:36:10:640PM | 930526021 | John Goetz | Toroidal field = 5.0T.
Plasma current = 20 kAmps Bz now -5mT Shot should have gone. Null looks o.k. Changes for shot 022: IC_EF4 changed from 700 to 740Amps at 1msec to try and reduce Bz more. |
| May 26 1993 03:54:24:550PM | 930526022 | John Goetz | Toroidal field = 5.0T.
Plasma current = 180 kAmps Current rise is 150kAmps in 45msec. Only makes 180kAmps. Current rampdown finds a plateau around 100kA, but then continues the ramp with termination at 270msec. Discharge position is better this shot - moves out during middle and then back in. Bz still -5mT. Nl_05 is progressively getting worse. Please disregard this density information. Changes for shot 023: None |
| May 26 1993 04:04:13:540PM | 930526023 | John Goetz | Toroidal field = 5.0T.
Plasma current = 30 kAmps Changes for shot 024: EF3 PLC current limit set to 20kAmps from 15kAmps |
| May 26 1993 04:24:59:210PM | 930526024 | John Goetz | Toroidal field = 5.0T.
Plasma current = 190 kAmps Peaks at 70msec and then ramps down with disruptions all the way down. Plateau at 100kAmps. Radial position is much better beginning at 70msec. Changes for shot 025: OH1 crowbar to 50msec from 40msec. No change on the V waveform. (Trying to fix the fact that the plasma moves in at the crowbar time due to differences in OH1 and OH2's) |
| May 26 1993 04:51:37:320PM | 930526025 | John Goetz | Toroidal field = 5.0T.
Plasma current = 30 kAmps. EF3's have funny waveform due to feedback with high gain on a no plasma shot Changes for shot 026: Proportional gain for RCUR PID changed from 10 to 1 and start time from 50 to 24msec. EF3 PLC limit set back to 15kAmps |
| May 26 1993 05:03:15:650PM | 930526026 | John Goetz | Toroidal field = 5.0T.
Plasma current = 270 kAmps. Flattop from 70 to 140msec. No disruptions on rampdown until power supply inversion time at 250msec. Position is still a bit low and inside. Change of OH1 crowbar smoothed out OH1 and OH2 waveforms. Changes for shot 026: OH1 and OH2's voltage programming extended to 300msec. TF and OH inversion times set to 350msec. |
| May 26 1993 05:09:24:200PM | 930526027 | John Goetz | Toroidal field = 5.0T.
Plasma current = 20 kAmps. Last shot of the day. |
| Physics Operator Comments |
| Engineering Operator Comments | ||||
| Shot | Time | Type | Status | Comment |
| 1 | 09:21:24:410AM | Plasma | Ok | low Plasma Power supplies OK |
| 2 | 10:05:23:330AM | Plasma | Ok | Good |
| 3 | 10:17:32:480AM | Plasma | Ok | good |
| 4 | 10:30:44:170AM | Plasma | Ok | Low Plasma I OH1 power Supply voltage Intermittant |
| 5 | 10:57:11:230AM | Plasma | Ok | Plasma Current 210 KA. |
| 6 | 11:33:41:210AM | Plasma | Ok | Plasma I 160KA. |
| 7 | 11:51:47:280AM | Plasma | Ok | good shot |
| 8 | 12:12:22:120PM | Plasma | Ok | Plasma Shot Low Current Plasma |
| 9 | 12:22:47:750PM | Plasma | Ok | Plasma Shot 200 KA. |
| 10 | 12:37:34:500PM | Plasma | Ok | Good Plasma Shot 210KA. |
| 11 | 12:56:57:620PM | Plasma | Ok | Fuse Loss tf Caninet #4 |
| 12 | 01:11:12:800PM | Plasma | Ok | plasma shot 200KA |
| 13 | 01:25:04:070PM | Plasma | Ok | 20ka plasma no faults |
| 14 | 01:34:05:930PM | Plasma | Ok | 30ka plasma |
| 15 | 01:47:18:830PM | Plasma | Ok | 80ka plasma |
| 16 | 02:11:25:160PM | Plasma | Ok | 220ka |
| 17 | 02:24:23:930PM | Plasma | Ok | 30ka plasma current |
| 18 | 02:37:39:690PM | Plasma | Ok | 220ka plasma |
| 19 | 03:00:44:720PM | Plasma | Ok | No PLasma Current |
| 20 | 03:13:31:910PM | Plasma | Ok | no plasma current. |
| 21 | 03:23:20:290PM | Plasma | Ok | Low Plasma current. |
| 22 | 03:37:47:620PM | Plasma | Ok | Good Plasma shot Current 180ka |
| 23 | 03:55:34:710PM | Plasma | Ok | low plasma |
| 24 | 04:06:11:770PM | Plasma | Ok | Plasma Current 190 KA. |
| 25 | 04:24:09:060PM | Plasma | Ok | Plasma shot low current |
| 26 | 04:51:21:300PM | Plasma | Ok | Very good shot Plasma current 270KA. |
| 27 | 05:02:45:830PM | Plasma | Ok | Long pulse low plasma cvurrent. |