| Miniproposals | ||||||||||
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| Operators | |
| Session leader(s): | Nils Basse |
| Physics operator(s): | Bill Rowan |
| Engineering operator(s): | Bill Cochran,Bill Byford,Bill Parkin |
| Engineering Operator Run Comment |
| MP 366 TAE/MP 367A q-ranps SL:Snipes/Basse PO:Rowan EO:Cochran/Byford/Pa |
| Session Leader Plans |
| Physics Operators Plans |
| Session Leader Summaries |
| Entered: Jul 7 2004 03:49:03:740PM |
| Author: Nils Basse |
| Session Leader Summary for Friday, March 19, 2004 (1040319) Purpose: MP 367A: Interplay between confinement, turbulence and magnetic topology Physics operator : Rowan Session leader : Basse ------------------------------------------------------------------------ See the Physop Summary for technical details. Tough run. These plasmas seem to be very hard to sustain (as was also found for the first attempt December 3, 2003). Apart from plasma trouble we had additional hardware issues to battle: Breaker, CAMAC, computer and ICRF problems. First plasma was made on shot 5 (first 4 were cycle, engineering tests and a no power shot). Last plasma was shot 21. Good data was taken with both reflectometry and PCI throughout the day, and in spite of our various problems we did get some shots with good current ramps. Main problem was to keep density and ICRF steady while simultaneously ramping the current. The conclusion on whether we see a slow confinement transition with the fluctuation diagnostics remains fuzzy; in some cases (e.g. shot 21) a rather clear spin down in frequency is observed on PCI as q_a is lowered. This looks very much like the behaviour of stellarator high-k turbulence observations. In other cases, no clear indication of changes is observed. For early shots the density was high and uncontrolled due to the inner wall limited discharges. In later shots we managed to control the density but had a few disruptions when we tried to increase the density too rapidly. D transmitter fell out in shot 7 and never recovered. So we only had E left. Some data (including reflectometry) was lost around shots 11-13. |
| Physics Operator Summaries |
| Entered: Jul 7 2004 04:36:49:567PM |
| Author: Bill Rowan |
| Physop Summary for March 19, 2004. Run 1040319. Purpose: MP# 367A: Interplay between confinement, turbulence and magnetic topology Session Leader: N. Basse Physics Operator: W. Rowan Summary--------------------------------------------------------------------------- Discharge The discharge requested for this run is 1031203019. This is an inner wall limited discharge with a current ramp that is intended to reduce q-95 to approximately 2.6 by the end of the discharge. The discharge 1031203019 is adequate for this experiment but post mortem for run 1031203 indicated that improvements might include changes in the engineering limits for OH1, OH2_L, and OH2_U and some up/down symetrization of the configuration. Those were both implemented during this run. Segment 1 was taken from 1040317031 and the prefill, PG4, was reduced by 2 ms to 15 ms. The run ended due to a fault in a breaker which could not be corrected before 5pm. Significant time was lost due to this breaker fault and due to attempts to diagnose the failure of an RF transmitter (see below). Configuration The configuration was symmetrized by making RXU and RXL waveforms the same and by making ZXL the negative of ZXU. The gains on RXU and RXL were made the same and the gains on the ZXL and ZXU were made the same. An example of the result of this is shot 011. Density control The density on the early shots exceeded the demand of nl_04 = 1.0e+20 by more than a factor of 2. During the increase, the gas valve indicated closed. This inner wall limited plasma is strongly fueled by the wall. The density dropped over a few shots to the point that it could be controlled. The density rise must occur slowly in this discharge. Attempts to program a density of 1.5e+20 earlier than approximately 1.0 s led to disruptions (see shots 016 through 018. RF One of the two remaining transmitters was lost during the run. This was due to failure of a drive shaft linkage for a motor driven variac. Score Card---------------------------------------------------------------------- Plasmas 12 005,006,007,008,009,010, 011,012,013,015,018,021 Cycle and engineering tests 3 001,002,003 Early disruptions 3 016,017,020 Fizzles 1 019 No power shots 2 004,014 (computer problems) Total 21 Details------------------------------------------------------------------------- Engineering setup for Friday, March 19, 2004 MP# 367A (basse) q-ranps Session leader: N. Basse Physics operator: W. Rowan ECDC overnight in D2 at 2e-4 Torr, stopping by 07:00. Bake at 60 C overnight as well. Run begins at 09:00 and ends at 17:00. Power systems the same as 1031203019 A-coils should be enabled in the standard configuration. 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) Disable NINJA Enable the following gate valves, assuming no vacuum problems: ECE, VUV, DNB ------------------------------------------------------------------------------- RF Setup: Available transmitters in run-on by 8 am ------------------------------------------------------------------------------- Load 1031203019 Loaded segment 1 from 1040317031 and reduced the prefill PG4 from 17 ms to 15 ms 001. Cycle test 002. Cycle test 003. Engineering test 004. No power shot. Computer problems during init A-coils are enabled for this shot and until noted otherwise. 005. Plasma Disruption at 1.4s Density is high. Gas valve is off. This is an uncontrolled ne rise. Suspect wall fueling. nl_04 = 2.5 at 1.2 s Next shot. OH1 lower limit changed to -30 OH2_L lower limit changed to -30 OH2_U lower limit changed to -30 006. Plasma density still too high. has come done to 1.8 from 2.5 on the previous shot Next shot Add 1 ms to prefill. PG4 changed from 15 to 16 ms Changed the demand for ZXU to 0.04 m from 0.09 m 007. Plasma density still too high. ne approximately 1.8. next shot. changed the oh2_l limit from -30 to -35: [-35,30] changed the oh2_u limit from -30 to -35: [-35,30] copied rxu to rxl Reduced RF for the next shot. Problem with the controller for one of the two transmitters that we are using. Will continue with E 008. Plasma nl_04 = 1.2 at 1.2 s Vertical position oscillating before 1.5 s. Scrubbing the inner wall. Next shot. Add 1 ms to the prefill. PG4 changed from 16 to 17 ms. The prefill did not rise as much as I expected after the last change. Made the gains the same and equal to the lower on shot 007 for ZXU and ZXL Made the gains the same and equal to the lower on shot 007 for RXU and RXL 009. Plasma nl_04 = 1.4 at 1.2s Data acquisition on F-side pressure Next shot. Copied ZXU to ZXL then flipped ZXL 010. Plasma Disruption at 1.29 s F-side pressure = 0.042 mT nl_04 = 1.35e+20 at 1.1 s Next shot. No PCS changes. 011. Plasma ne = 1.0e+20 at 1.2 s Disruption at 1.7 s -- during rampdown Next shot. Decrease the outer gap by 1 cm from 2.5 to 1.5 012. Plasma ne = 1.5 e+20 at 1.4 s Power supply fault after the shot. Next shot. No PCS changes. 013. Plasma ne = 1.25e+20 at 1.3 s Next shot. No PCS changes 014. No power shot. Problems with camac. Spurious i_square_t fault No power shot. Next shot. No PCS changes 015. Plasma Power supply fault after the shot. Next shot. Increased nl_04 demand to 1.5e+20 016. Plasma. Disruption at 0.7 s Next shot. No PCS changes 017. Plasma Disruption at 0.7 s again. Next shot. Reduced nl_04 demand to 1,0e+20 018. Plasma Disruption at 1.5 s Next shot Increased nl_04 demand to 1.5e+20 at 1s 019. Fizzle Next shot. Reduced BR_0 by 0.5 mT 020. Plasma Disruption at 0.5 s Once again, it appears that I am bringing the density up too rapidly. Next shot. Reduced the nl_04 demand to 1.0 until 0.5s. then started the ramp to 1.5 021. Plasma Disrupted in ramp down. nl_04 is not pretty but is higher after 1 s. Overshoots the demand of 1.5 Next shot. Increase nl_04 demand to 2.0e+20 rxl and rxu flat top at 2 cm extended beyond 1 s Last plasma attempt PF3 breaker will not close |
| Session Leader Comments | |||
| Mar 19 2004 09:02:19:790AM | Nils Basse | We'll begin by re-doing shot 1031203019, but with max available ICRF power (about 2.5 MW). Once a good discharge is established, we'll do scans of density, flattop current and ICRF power. | |
| Mar 19 2004 09:30:31:420AM | 1040319004 | Nils Basse | No power shot. |
| Mar 19 2004 09:48:11:213AM | 1040319005 | Nils Basse | First plasma, disrupts at 1.34 s. RF not happy, density rises up to 2.5 m-2 (programmed to 1). |
| Mar 19 2004 10:16:18:267AM | 1040319006 | Nils Basse | Plasma into rampdown. Density down from 2.5 to 1.8. |
| Mar 19 2004 10:34:07:200AM | 1040319007 | Nils Basse | Plasma, disrupts at 1.4 s. Density still ends up at 1.8 m-2. Plasma shaping better and some RF for this shot. No clear indications in turbulence of a clear confinement transition yet, although q at the limiter reaches 2.7. |
| Mar 19 2004 11:16:35:457AM | 1040319008 | Nils Basse | Density closer to the desired value, but rises at the end, probably due to vertical positioning problems. RF tuning becoming better, 1.2 MW from 0.5 to 0.88 s. Full length plasma, current reaches 1.3 MA as planned, minimum q_a 2.64. |
| Mar 19 2004 11:38:22:870AM | 1040319009 | Nils Basse | Plasma, disrupts late. Good current, RF. Density continually rises up to 1.8 m-2. Some signs of transition in refl. measurements, no clear indications on PCI. |
| Mar 19 2004 11:52:43:590AM | 1040319010 | Nils Basse | Good shot until disruption at 1.3 s. Density lower but still not controlled. |
| Mar 19 2004 12:26:38:613PM | 1040319011 | Nils Basse | Plasma into rampdown, density at requested level. RF trips once at 0.9 s and drops out at 1.4 s. Only change for next shot is to decrease the outer gap by 1 cm. |
| Mar 19 2004 12:57:23:360PM | 1040319012 | Nils Basse | Plasma into rampdown. No RF, current and q_a not reaching a low level. |
| Mar 19 2004 01:04:13:070PM | 1040319013 | Nils Basse | Good shot, but RF drops out at 1 s and density remains non-controlled. If we can get a full RF pulse for this type of shot that's our baseline for parameter scans. |
| Mar 19 2004 02:29:57:447PM | 1040319014 | Nils Basse | No power shot. |
| Mar 19 2004 02:37:57:333PM | 1040319015 | Nils Basse | Plasma, all OK except RF which didn't start at 0.8 s as expected due to software problems. Also tripped at 1.15 s. For next shot begin a density scan by requesting 1.5 m-2. |
| Mar 19 2004 02:50:44:847PM | 1040319016 | Nils Basse | Disruption at 0.7 s. Density does seem to flatten at 1.5 m-2 as programmed. |
| Mar 19 2004 03:00:29:630PM | 1040319017 | Nils Basse | Disruption at 0.7 s as for shot 16. We'll pull back density to 1.0 m-2 for the next shot. |
| Mar 19 2004 03:41:05:270PM | 1040319018 | Nils Basse | Good shot. Try to increase density to 1.5 m-2 more slowly next shot. |
| Mar 19 2004 03:46:44:133PM | 1040319019 | Nils Basse | Fizzle. |
| Mar 19 2004 03:53:41:767PM | 1040319020 | Nils Basse | Disruption at 0.55 s. Will try to bring up density more slowly for the next shot. |
| Mar 19 2004 04:23:46:583PM | 1040319021 | Nils Basse | Good plasma at 1.5 m-2, although minimum q_a is only 2.79 due to changes in current and triangularities. Next shot we'll increase density to 2.0 m-2 and try to fix q_a. |
| Mar 19 2004 04:56:32:023PM | 1040319022 | Nils Basse | No power test. End of run. |
| Physics Operator Comments | |||
| Mar 19 2004 07:25:23:590AM | Bill Rowan | Engineering setup for Friday, March 19, 2004 MP# 367A (basse) q-ranps Session leader: N. Basse Physics operator: W. Rowan ECDC overnight in D2 at 2e-4 Torr, stopping by 07:00. Bake at 60 C overnight as well. Run begins at 09:00 and ends at 17:00. Power systems the same as 1031203019 A-coils should be enabled in the standard configuration. 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) Disable NINJA Enable the following gate valves, assuming no vacuum problems: ECE, VUV, DNB ------------------------------------------------------------------------------- RF Setup: Available transmitters in run-on by 8 am ------------------------------------------------------------------------------- | |
| Mar 19 2004 08:21:08:960AM | Bill Rowan | Load 1031203019 Loaded segment 1 from 1040317031 and reduced the prefill PG4 from 17 ms to 15 ms | |
| Mar 19 2004 07:49:56:323AM | 1040319001 | Bill Rowan | 001. Cycle test |
| Mar 19 2004 09:13:42:550AM | 1040319002 | Bill Rowan | 002. Cycle test |
| Mar 19 2004 09:13:21:187AM | 1040319003 | Bill Rowan | 003. Engineering test |
| Mar 19 2004 09:30:02:543AM | 1040319003 | Bill Rowan | 004. No power shot. Computer problems during init A-coils are enabled for this shot and until noted otherwise. |
| Mar 19 2004 10:34:34:953AM | 1040319005 | Bill Rowan | 005. Plasma Disruption at 1.4s Density is high. Gas valve is off. This is an uncontrolled ne rise. Suspect wall fueling. Next shot. OH1 lower limit changed to -30 OH2_L lower limit changed to -30: [-35,30] OH2_U lower limit changed to -30: [-35,30] |
| Mar 19 2004 10:09:45:163AM | 1040319006 | Bill Rowan | 006. Plasma Next shot Add 1 ms to prefill. PG4 changed from 15 to 16 ms Changed the demand for ZXU to 0.04 m from 0.09 m |
| Mar 19 2004 10:27:52:900AM | 1040319007 | Bill Rowan | 007. Plasma density still too high. ne approximately 1.8. next shot. changed the oh2_l limit from -30 to -35 changed the oh2_u limit from -30 to -35 copied rxu to rxl |
| Mar 19 2004 11:01:03:840AM | 1040319007 | Bill Rowan | Reduced RF for the next shot. Problem with the controller for one of the two transmitters that we are using. Will continue with E |
| Mar 19 2004 11:12:47:413AM | 1040319008 | Bill Rowan | 008. Plasma nl_04 = 1.2 at 1.2 s Next shot. Add 1 ms to the prefill. PG4 changed from 16 to 17 ms. The prefill did not rise as much as I expected after the last change. |
| Mar 19 2004 11:19:47:400AM | 1040319008 | Bill Rowan | Made the gains the same and equal to the lower on shot 007 for ZXU and ZXL Made the gains the same and equal to the lower on shot 007 for RXU and RXL |
| Mar 19 2004 11:38:42:697AM | 1040319009 | Bill Rowan | 009. Plasma nl_04 = 1.4 at 1.2s Data acquisition failure on F-side pressure Next shot. Copied ZXU to ZXL then flipped ZXL |
| Mar 19 2004 11:58:34:080AM | 1040319010 | Bill Rowan | 010. Plasma Disruption at 1.29 s F-side pressure = 0.042 mT nl_04 = 1.35e+20 at 1.1 s Next shot. No PCS changes. |
| Mar 19 2004 12:23:24:773PM | 1040319011 | Bill Rowan | 011. Plasma ne = 1.0e+20 at 1.2 s Disruption at 1.7 s -- during rampdown Next shot. Decrease the outer gap by 1 cm from 2.5 to 1.5 |
| Mar 19 2004 12:46:24:103PM | 1040319012 | Bill Rowan | 012. Plasma ne = 1.5 e+20 at 1.4 s Power supply fault after the shot. Next shot. No PCS changes. |
| Mar 19 2004 12:57:55:470PM | 1040319013 | Bill Rowan | 013. Plasma ne = 1.25e+20 at 1.3 s Next shot. No PCS changes |
| Mar 19 2004 02:22:49:530PM | 1040319014 | Bill Rowan | 014. No power shot. Problems with camac. No power shot. Next shot. No PCS changes |
| Mar 19 2004 02:36:34:797PM | 1040319015 | Bill Rowan | 015. Plasma Power supply fault after the shot. Next shot. Increased nl_04 demand to 1.5e+20 |
| Mar 19 2004 02:48:59:997PM | 1040319016 | Bill Rowan | 016. Plasma. Disruption at 0.7 s Next shot. No PCS changes |
| Mar 19 2004 03:03:21:140PM | 1040319017 | Bill Rowan | 017. Plasma Disruption at 0.7 s again. Next shot. Reduced nl_04 demand to 1,0e+20 |
| Mar 19 2004 03:19:57:603PM | 1040319018 | Bill Rowan | 018. Plasma Disruption at 1.5 s Next shot Increased nl_04 demand to 1.5e+20 at 1s |
| Mar 19 2004 03:59:35:657PM | 1040319020 | Bill Rowan | 020. Plasma Disruption at 0.5 s Once again, it appears that density is rising too rapidly Next shot. Reduced the nl_04 demand to 1.0 until 0.5s. then started the ramp to 1.5 |
| Mar 19 2004 04:10:55:647PM | 1040319021 | Bill Rowan | 021. Plasma Disrupted in ramp down. nl_04 is not pretty but is higher after 1 s. Overshoots the demand of 1.5 Next shot. Increase nl_04 demand to 2.0e+20 |
| Mar 19 2004 04:24:00:960PM | 1040319021 | Bill Rowan | rxl and rxu flat top at 2 cm extended beyond 1 s |
| Mar 19 2004 05:00:51:540PM | 1040319022 | Bill Rowan | Last plasma attempt PF3 breaker will not close |
| Engineering Operator Comments | ||||
| Shot | Time | Type | Status | Comment |
| 1 | 07:41:56:840AM | Test | Ok | |
| 2 | 08:26:56:753AM | Test | Ok | |
| 3 | 09:10:25:850AM | Test | Ok | |
| 5 | 09:40:13:140AM | Plasma | Ok | |
| 6 | 09:57:11:823AM | Plasma | Ok | |
| 7 | 10:13:37:020AM | Plasma | Ok | |
| 8 | 11:04:15:413AM | Plasma | Ok | |
| 9 | 11:21:07:933AM | Plasma | Ok | |
| 10 | 11:41:11:550AM | Plasma | Ok | |
| 11 | 12:14:15:710PM | Plasma | Ok | |
| 12 | 12:30:51:957PM | Plasma | Ok | |
| 13 | 12:48:52:190PM | Plasma | Ok | |
| 14 | 02:19:04:190PM | Plasma | Ok | |
| 15 | 02:28:29:223PM | Plasma | Ok | |
| 16 | 02:43:16:930PM | Plasma | Ok | |
| 17 | 02:56:18:210PM | Plasma | Ok | |
| 18 | 03:09:49:147PM | Plasma | Ok | |
| 19 | 03:26:36:970PM | Plasma | Ok | |
| 20 | 03:47:20:290PM | Plasma | Ok | OH1 self power circuit fired during disruption |
| 21 | 04:05:24:520PM | Plasma | Bad | IOC OH2U pulled breaked, killed shot at 1.75 sec |
| 22 | 04:55:27:723PM | Test | Ok | |
| 23 | 05:09:31:807PM | Test | Ok | |