| Miniproposals | ||||||||||
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| Operators | |
| Session leader(s): | John Goetz |
| Physics operator(s): | Ian Hutchinson |
| Engineering operator(s): | Frank Silva |
| Engineering Operator Run Comment |
| 021 |
| Session Leader Plans |
| Physics Operators Plans |
| Session Leader Summaries |
| Entered: Jul 7 2004 03:49:08:477PM |
| Author: To Be Determined |
| Run Summary for 10 Aug 93 IHH, JG. Objectives were: (1) Get EF4 current reversal going with plasma. Engineering tests today looked good. Zero current at ~100ms, 35ms pause, negative ramp at nearly the same voltage, about -700, limited by the hybrid demand. Well done, engineers! (...so far!!). (2) Obtain elongated and diverted plasmas. We have the limiter moved out to 0.96m to help give some more space. We shall start with only -1cm on the zcur. (3) Observe the effect of the EF4 reverse swing on the RXpoint position. (4) Try to feedback on this. Only (2) was achieved because the others depended on EF4 which did not reverse reliably. It is clear that we have insufficient EF4 voltage to ramp to zero in less than ~200ms when fighting the EF3 etc. However, substantial development work improved the current rise and obtained interesting diverted shapes for the first time since going to higher OH precharge. Scorecard: 4 duds. 2 Fizzles. 20 plasmas. Not bad for Tuesday. Shot summary for 930810. 1 Chopper off. p_0=1.2e-5 EF4@1090 B_z+ve, Fiz. 2 Ratiomatic was off. EF4@1040 Crashed in 15ms Fiz. 3 p_0=1.0e-5 Ratiomatic on. Disrupt @ 170ms Plasma 4 Lowered pulse gas. Disrupt @ 220ms Plasma 5 Chopper on. Lowered gas more. EF3 -2200V. EF4 invert lowered at 200ms. Chopper threw plasma out at 150ms Plasma 6 Chopper limit lowered. Halved B side gas initial. EF4 -1000V. EF4 current demand changed. Longer shot. EF4 did not reverse. Plasma Plasma rides high for a long time. 0.5MA. 7 Chopper off. Lowered gas init. Argon on. Lower later Oh1&2 demand. Good but plasma still high. Puzzle. Plasma 8 Added gas ~100ms. EF4 -700V. Dud 9 p_0=1.1e-5. Still a vertical excursion. Plasma 10 Raised Ef1/2. Tweaked OH2LV to help position. No EF4 reverse. Plasma 11 Tweaked OH2 another 5V. Raised EF1 early. Upper x. Plasma 12 OH2L 5V tweak later. Raised EF1 early some more. Prolonged the OH V-program after 300ms. Turn off EF4 reversal...PS problems. Dud 13 p_0=1.2e-5. EF4 1065A. Doubled the A-port gas. Disrupts @ 210ms. Current rise was bad. Perhaps because of the long wait we had because of IGOR. Plasma 14 Repeat. Still a bad rise. Plasma 15 Took out the EF4 change. Now 1050A. Increased ZCUR P to 1.0 from 0.4. Still bad rise, moving in. Plasma 16 p_0=1.0e-5. Dud 17 p_0=1.2e-5. Oh1 voltage made more negative to move out. Plasma 18 Lowered B-gas by 1/3. Still disruptive. Plasma 19 EF4 early inversion increased. Ef1 inversion increased. changed OH2 position tweak. Disrupted at 210 as before. Plasma 20 Reloaded shot 11. Disruptive like the others. Demonstrates it was nothing we did. Plasma 21 Reload shot 19. EF4 current to 2200. OH2l(dif) P=.1. Plasma 22 Lowered gas turn of argon. Better current rise. Plasma 23 ZCUR gains raised a lot. (p=4,d=4). Disruptive. Plasma 24 Raised EF3 V to -2300 at 50 ms. Long shot riding low. There seems to be something wrong with the zcur predictor; however we have a great current rise. Plasma 25 Raised EF1 current to 2500A. Added a second A puff. Plasma 26 EF1 2700A. EF3-100V more. raised second puff Dud SOME MORE DETAILS: Moving the OH1 crowbar removed most of the position problems as expected. EF4 current reversal was not reliable. The PS seemed to push current back up when it neared zero. Engineering gave up and went to 2-quadrant at shot 12. Thereafter we were simply ramping to zero as fast as possible. The gas was way too high to begin with (settings of 930804029) the B-side total was lowered by nearly a factor of four. So that by shot 9 we had a reasonable current rise with good position control. Shot 11 was good. However, from then till 22 the gas seemed still to be choking the current rise. Further lowering and turning off argon helped the rise so much that we then had to increase the EF3 (negative) voltage to compensate the outward motion of the plasma during the rise because the rate of current rise was so much better. OH2s were found to have a noticeable imbalance in the power-supply response to equal demand. OH2L gave about 20% more voltage in inversion than OH2U. This made the plasma move up steadily from about 120ms onward. The voltage demand was tweaked by hand from shot 10 on, to balance this. The position feedback was not able to compensate with the gains we had. On shot 23 we discoverd the reason for this; namely that we had reduced the M's of the zcur to allow a greater gain, so that the chopper could be put into this predictor with enough sensitivity. However, the gains on PD were not turned up. Therefore prior to 23 the plasma had ~10 times less feedback gain on the vertical position which explains why it was behaving in that way! On shot 22 and following, the zcur predictor broke because the Bp coil BP17 broke. This caused predictors based on the BC set to think that the plasma is higher than it is. Consequently the plasma was moved down by about 5cm. This gave some pretty interesting shapes on 25. Despite a plasma moved down by 5 cm, the symmetric EF3 currents give a nearly double null divertor. The chopper was turned on for shots 5 and 6. It also had the effect of moving the plasma up. However, it was not to blame for the longer time-scale drift. That was the OH2. Engineering problems required us to turn it off. It needs debugging so we went ahead without it. The several duds that we had were indicative, it seems, of TOO LOW a fill pressure. With luck we have now got a window for raising the fill pressure; since running with lower than 1.2e-5 can give duds. There may be some drift up of the lowest allowable with time. Recommendation: use 1.2e-5 or more once operation is established. |
| Physics Operator Summaries |
| Session Leader Comments | |||
| Aug 10 1993 09:10:49:700AM | John Goetz | Run 930810
EO: Silva PO: Hutchinson APO: Goetz Objectives for today's run follow from MP019 - Discharge Development under the topic of x-point control. 1 - Get EF4 current reversal going with plasma 2 - Obtain elongated and diverted plasmas (the limiter is out to 0.96m; ZCUR = -.01m) 3 - Observe the effect of EF4 reverse swing on the R_XL (radius of lower x-point) 4 - Feedback on R_XL | |
| Aug 10 1993 11:37:34:110AM | John Goetz | Run 930810
Shot 006 Good plasma - 490kA - some flattop - 500+ msec disruption at 75msec - triggered by chopper turn on density falls - Halpha rises - plasma is in and high Changes for 007: chopper off lower fueling puff early in time | |
| Aug 10 1993 09:49:27:860AM | 930810001 | John Goetz | Run 930810
Shot 001 New OH2 controllers installed. New KAPPA, RXL, and ZXL predictors installed, although the PID's are zeroed. S_EF4 and V_EF4 programmed to ramp EF4 down rapidly and reverse the current. Fizzle Bz was a little too positive at t=0. EF4 did reverse but there was a blip before reversal Changes for 002: Lower EF4 to 1090 |
| Aug 10 1993 10:08:00:050AM | 930810002 | John Goetz | Run 930810
Shot 002 Fizzle Bz o.k. Density rises quickly (too quickly?) Changes for 003: Lower fill pressure to 1.0e-5 from 1.2e-5 |
| Aug 10 1993 10:28:00:210AM | 930810003 | John Goetz | Run 930810
Shot 003 Plasma - 200kA vertical position lost beginning at 135 msec and disr. at 160 too much gas?!?! according to scatterplot history Changes for 004: PULSE_GAS_1 off PULSE_GAS_2 dropped from 80V to 60V PULSE_GAS_3 spike width halfed |
| Aug 10 1993 10:44:29:190AM | 930810004 | John Goetz | Run 930810
Shot 004 Plasma - 370kA; vertical disruption at 220 msec trouble during current rise - many mini disruptions running inside on the limiter the whole shot Changes for 005: lower the fueling gas some more change V_EF3 from -2400 to -2200 @26msec to help push out the plasma |
| Aug 10 1993 11:10:02:240AM | 930810005 | John Goetz | Run 930810
Shot 005 Plasma - 290 kAmps - disruption at 150 msec current rise smoother this shot vertical position control lost @66msec - choppah problems Changes for 006: V_EF4 changed to -1000V from -700V @t=0 lowered fuel gas |
| Aug 10 1993 12:09:40:230PM | 930810007 | John Goetz | Run 930810
Shot 007 Plasma - 470kA - good flattop - 500+ msec plasma is running high - OH2's imbalanced - puzzling behavior no EF4 reversal Changes for 008: chopper on at 400msec added fuel gas at 70msec to fill in density dip changed V_EF4 to -700 from -1000 |
| Aug 10 1993 12:22:23:140PM | 930810008 | John Goetz | Run 930810
Shot 008 Dud EF4 reversed no magnetics problem Changes for 009: up fill pressure to 1.1e-5 |
| Aug 10 1993 12:45:05:450PM | 930810009 | John Goetz | Run 930810
Shot 009: 450 kA for 100msec flattop chunk taken out of current rise @115msec plasma begins to move up @140msec EF4 has current reversal Changes for 010: made OH2l voltage demand less negative from 100 to 200 msec raise EF1 and EF2 demands |
| Aug 10 1993 01:07:43:700PM | 930810010 | John Goetz | Run 930810
Shot 010: plasma - 450kA - 100+msec flattop ZCUR position now +2.5 instead of +5. - V_OH2 tweaks worked upper divertor at 375msec - kappa~1.4 -> ~1.6 at diversion no EF4 reversal Changes for 011: more V_OH2L tweaks to remove imbalance up V_EF1 to -200V (less negative) early for more elongation |
| Aug 10 1993 01:25:06:970PM | 930810011 | John Goetz | Run 930810
Shot 011: 500kA - 100msec flattop - upper divertor @ 370msec ZCUR control o.k. until 250msec - plasma begins to move up to +4cm current rise smoothed out with the EF1 tweak Changes for 012: tweak V_OH2L late in time to help out ZCUR made V_EF1 less negative early prolonged V_OH1 and V_OH2's late (after 350msec) |
| Aug 10 1993 01:38:04:820PM | 930810012 | John Goetz | Run 930810
Shot 012: Dud - Bz on the edge of goodness (according to scatterplot) Changes for 013: up fill pressure to 1.2e-5 raise IC_EF4 by 15A to 1065A |
| Aug 10 1993 02:09:56:640PM | 930810013 | John Goetz | Run 930810
Shot 013: plasma - disruption @215msec hard x-ray bursts beginning @125msec - current rolls over - plasma moves in and down at this time disruption is up and out current rise is slow Changes for 014: no changes |
| Aug 10 1993 02:27:17:270PM | 930810014 | John Goetz | Run 930810
Shot 014: plasma - disruption at 220 msec - loose control down and in ugly shot no hards Changes for 015: up P gain on ZCUR to 1.0 (from 0.4) IC_EF4 down 15A to 1050A |
| Aug 10 1993 02:38:50:290PM | 930810015 | John Goetz | Run 930810
Shot 015: Plasma - almost a trace over of 014. Changes for 016: lower fill pressure to 1.0e-5 |
| Aug 10 1993 02:53:08:120PM | 930810016 | John Goetz | Run 930810
Shot 016: Dud - fill pressure too low Changes for 017: raise fill to 1.2e-5 make V_OH1 more negative from 20 -> 50msec to push plasma off inner wall |
| Aug 10 1993 03:07:33:950PM | 930810017 | John Goetz | Run 930810
Shot 017: plasma - disruption @215 msec - riding in too far early in time begins moving down at ~170msec Changes for 018: lowered fueling pulse by ~30% |
| Aug 10 1993 03:20:53:750PM | 930810018 | John Goetz | Run 930810
Shot 018: plasma - disruption @ 225msec plasma begins to move down @ 180 msec Changes for 019: tweak V_OH2L @ 200 msec (make it 5V more negative) to help the ZCUR lower V_EF1's to -190V @50 msec to help with current rise |
| Aug 10 1993 03:32:13:100PM | 930810019 | John Goetz | Run 930810
Shot 019: plasma - disruption @ 225msec - bad current rise plasma begins to move up at 170msec Changes for 020: reload 930810011 in an attempt to find a good shot |
| Aug 10 1993 03:50:24:180PM | 930810020 | John Goetz | Run 930810
Shot 020: ugly shot - current rise is terrible - disruption @210msec plasma dies down Changes for 021: reload shot 930810019 lowered EF1 current to 2200A (from 2400) put OH2L (difference) P=0.1 for all time |
| Aug 10 1993 04:06:13:380PM | 930810021 | John Goetz | Run 930810
Shot 021: bad current rise - disruption @250msec - plasma starts down @225msec mini-disruption @130msec Changes for 022: turn off PULSE_GAS_1 (Ar) lower both fueling pulses |
| Aug 10 1993 04:26:13:900PM | 930810022 | John Goetz | Run 930810
Shot 022: bad current rise - plasma recovers and reaches 430kA and 525msec ZCUR controller having almost no effect lower divertor when plasma is down (almost down the slot) Changes for 023: up P gain on ZCUR to 4.0 |
| Aug 10 1993 04:37:53:690PM | 930810023 | John Goetz | Run 930810
Shot 023: plasma - disruption @ 210msec - plasma too far out during current rise plasma moves down Changes for 024: lower V_EF3 to -2300V (from -2100) @50msec to keep the plasma inside |
| Aug 10 1993 04:54:16:600PM | 930810024 | John Goetz | Run 930810
Shot 024: plasma - 550kA - 550msec - no disruption - smooth current rise lower divertor around 400msec stuffed into the slot around 250 msec Changes for 025: added second spike to PULSE_GAS_3 raised EF1 current to 2500A (try and really divert the next plasma) |
| Aug 10 1993 05:05:33:290PM | 930810025 | John Goetz | Run 930810
Shot 025: plasma - 450kA - 550msec chunk taken out of current rise at 130msec diverted from 180msec on (lower) Changes for 026: raise EF1 current to 2700A lower EF3 voltage to -2400V |
| Aug 10 1993 05:21:47:240PM | 930810026 | John Goetz | Run 930810
Shot 026: Dud Fill pressure acceptable Magnetics acceptable |
| Aug 10 1993 05:36:38:470PM | 930810028 | John Goetz | test
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| Physics Operator Comments |
| Engineering Operator Comments | ||||
| Shot | Time | Type | Status | Comment |
| 1 | 09:30:18:810AM | Plasma | Ok | ef4 double swing |
| 2 | 09:50:32:640AM | Plasma | Ok | bd |
| 3 | 10:10:32:220AM | Plasma | Ok | better |
| 4 | 10:27:41:310AM | Plasma | Ok | better |
| 5 | 10:44:50:140AM | Plasma | Ok | all tmx supplies operated chopper inop |
| 6 | 11:08:57:840AM | Plasma | Ok | ef4 tmx c opened reset |
| 7 | 11:33:16:340AM | Plasma | Ok | no chopper, tmx ef4c opened |
| 8 | 12:00:45:140PM | Plasma | Bad | ef4 tmx ok |
| 9 | 12:20:32:610PM | Plasma | Ok | plasma |
| 10 | 12:45:19:490PM | Plasma | Ok | Shoot through on ef4. |
| 11 | 01:05:56:870PM | Plasma | Ok | had to wait |
| 12 | 01:24:21:520PM | Plasma | Ok | no plasma |
| 13 | 01:57:43:740PM | Plasma | Bad | plasma |
| 14 | 02:11:54:280PM | Plasma | Ok | plasma |
| 15 | 02:28:58:830PM | Plasma | Ok | plasma |
| 16 | 02:42:49:100PM | Plasma | Bad | fizzel |
| 17 | 02:55:23:040PM | Plasma | Ok | sparker |
| 18 | 03:09:37:010PM | Plasma | Ok | plasma |
| 19 | 03:23:44:590PM | Plasma | Ok | Olasma shot no faults |
| 20 | 03:37:27:480PM | Plasma | Ok | plasma shot No power supply faults. |
| 21 | 03:51:29:890PM | Plasma | Ok | plasma shot no faults. |
| 22 | 04:06:54:000PM | Plasma | Ok | ok |
| 23 | 04:23:47:880PM | Plasma | Ok | Plasma shot No faults. |
| 24 | 04:37:53:770PM | Plasma | Ok | Plasma shot No faults. |
| 25 | 04:52:56:480PM | Plasma | Ok | plasma |
| 26 | 05:06:41:710PM | Plasma | Ok | |
| 27 | 05:23:31:720PM | Test | Bad | no pulse -- igor bypassed |
| 28 | 05:29:26:040PM | Test | Ok | ef4 test ok |