| Miniproposals | ||||||||||
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| Operators | |
| Session leader(s): | Steve Wolfe |
| Physics operator(s): | Ron Parker,Steve Wolfe,Ron Parker |
| Engineering operator(s): | Andy Pfeiffer,Sam Pierson,Gary Dekow |
| Engineering Operator Run Comment |
| MP298A Plasma startup Session leaders: Wolfe, Irby Physics operator: Par |
| Session Leader Plans |
| Physics Operators Plans |
| Entered: Feb 8 2006 03:25:44:457PM |
| Author: Ron Parker |
| Engineering setup for Thursday 9 February 2006
MP298A Plasma startup Session leaders: Wolfe, Irby Physics operator: Parker Overnight ECDC in D2, and bake at 60 C. Run begins at 09:00 and ends at 17:00 Power systems as on 1051101001 (0.8 MA, 5.4 T, lower single null) A-coil configuration: normal [+Dtop -Dbot -Jtop +Jbot] and 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) leave NINJA as is Leave DISABLED Enable the following gate valves, assuming no vacuum problems: ECE, VUV Torvac setup: Gate valves open Run plan: Start from 1051101001 or successful shot from 1060208 and try to get reproducible full-length plasmas. If successful, use the plasmas to clean up the machine and slowly reduce the hydrogen content. |
| Session Leader Summaries |
| Physics Operator Summaries |
| Entered: Feb 9 2006 05:23:25:353PM |
| Author: Ron Parker |
| The run began amazingly well considering the long shutdown and relatively few cleanup runs. The first four discharges ran as programmed with long rampdowns to ~ 50 kA. However, the previously noted problem with the vertical TF leg at C-port continued, resulting in long recool times approaching 1 hour.
Beginning with shot 5, problems developed with the startup. Shot 5 fizzled, and shots 6-9 were duds. Various tweaks on the stray fields and gas pressure did not seem to help. Finally on shot 10, the plasma started up but disrupted at ~0.3 ms. Shot 11 fizzled and shot 12 was a TF test. Finally, the last shot, shot 13 ran beautifully. There is no explanation for the difference between the shots that didn't go and shots 1-4 and 13 that ran and ran well. The more serious problem is the lack of cooling on the vertical leg near C-port. The problem is being analyzed and potential solutions are under consideration. No decision regarding a fix was taken at the end of this run |
| Session Leader Comments | |||
| Feb 9 2006 11:20:48:870AM | 1060209005 | Steve Wolfe | Shot#5: Got a fizzle after a 50min delay for cooling oh2l seems to be ~1kA more negative than on previous shot. Supply seems to be following its demand. Br0 knows it's off by ~3mT, which is consistent with the Br0 reading from vacbrbz. The oh2 avg current error is +240 compared to -440 on shot 4. That's the difference, but I don't know why. |
| Feb 9 2006 11:33:34:097AM | 1060209005 | Steve Wolfe | Shot#5: The initial response of the oh2 power supplies (-1.1 to -1 sec) is different. The oh2u in particular has a sawtooth-like voltage that is not on demand or on oh2l Both voltages and demands are less negative at this time on shot 5 than shot 4. I think this is similar to last year, when Bill and Gary found an erroneous dc bias somewhere on the control board on oh2u. The oh2u current initially goes positive on shot 5, to ~+2000A at 1sec on shot 5, but on shot 4 both currents have a small positive spike and then go back close to zero until -1sec. |
| Physics Operator Comments | |||
| Feb 9 2006 09:21:30:640AM | 1060209001 | Ron Parker | First shot was programmed to follow shot 1060208022 from yesterday and ran
amazingly well. Interferometer is working, but not in feedback mode. We'll continue with this shot, next one without changes. |
| Feb 9 2006 09:40:23:927AM | 1060209002 | Ron Parker | Even more amazingly, shot 2 ran well. Density fell 0n n_e.L(4) to 0.3e20m-2.
We'll start injecting gas with PG3 to hold up the density. Nextshotwill have 40 ms at 30 volts on pg3. |
| Feb 9 2006 09:46:41:597AM | 1060209003 | Ron Parker | Shot 3 ran well with density level at n_eL(4)=0.6e20 m-2.
Let's see if it repeats. |
| Feb 9 2006 11:02:00:580AM | 1060209004 | Ron Parker | The shots keep coming without tuning. Long delay until shot 5, 55 minutes due to cooling problem in vertical leg at C-port.
Next: RF plus 30 ms Ar/Ne and RF |
| Feb 9 2006 12:30:35:140PM | 1060209005 | Ron Parker | Shot 5 fizzled. BR was very negative, ~ -.002 T although breakdown was prompt.Try again before tuning. Meanwhile cooling of TF continues to be a problem. |
| Feb 9 2006 11:39:15:503AM | 1060209006 | Steve Wolfe | Shot#6: Ron has gone to class so I'm taking over as Physop for an hour This was a dud. OH2U initial behavior was not as extreme as on shot 5 (current only went to +500A) but still not "right". Br0 was near 0 at t=0. I don't think Ron changed it? |
| Feb 9 2006 11:44:12:920AM | 1060209006 | Steve Wolfe | Shot#6: Ron has gone to class so I'm taking over as Physop for an hour This was a dud. OH2U initial behavior was not as extreme as on shot 5 (current only went to +500A) but still not "right". Br0 was near 0 at t=0. I don't think Ron changed it? Raise pg4 from 25 to 27msec. Keep an eye on the oh2 supplies; Bill C. is not in today. |
| Feb 9 2006 12:07:19:210PM | 1060209007 | Steve Wolfe | Shot#7: Raise pg4 from 25 to 27msec. Keep an eye on the oh2 supplies. Another dud! Br0 looks the same. So does the early oh2 (same as 6, not 4) OH2 currents at t=0 are nominal. I think I just didn't raise the pg4 enough (or too much?) There will be a 30 minute cell access for the LH crew. By the time they finish, Ron should be back. I'll raise the fill to 30msec; if he doesn't like it, he can change it. |
| Feb 9 2006 12:49:46:693PM | 1060209007 | Ron Parker | For shot 8, 3 ms more gas, 5 A less EF4 (1345-1350), +.0002 on BR
(Trying to reproduce field errors on shot 3) |
| Feb 9 2006 01:27:43:790PM | 1060209008 | Ron Parker | Dud! Try decreasing pressure, from 30 to 25 ms for next shot.
Also, decrease EF4 current by 5 A again. A thermocouple failure led to a loss of vessel heating. Now repaired. Total delay ~ 50 minutes. |
| Feb 9 2006 01:52:25:950PM | 1060209009 | Ron Parker | Shot 9 was another dud.
Setting up ECDC for 30 minutes. Also back to -1345 on EF4. |
| Feb 9 2006 03:50:24:920PM | 1060209010 | Ron Parker | Shot 10 started up, a small victory, but disrupted at ~0.3 s. |
| Feb 9 2006 03:56:48:730PM | 1060209011 | Ron Parker | Shot 11 fizzled. Try again, reduce pressure by 2ms (to 23) |
| Feb 9 2006 04:28:49:297PM | 1060209012 | Ron Parker | Shot 12 was a TF test |
| Feb 9 2006 04:39:08:810PM | 1060209012 | Ron Parker | We'll try one more shot. Clearly, the magnet cooling problem has to be addressed.
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| Feb 9 2006 05:03:45:627PM | 1060209013 | Ron Parker | Shot 13 ran well -- why? |
| Engineering Operator Comments | ||||
| Shot | Time | Type | Status | Comment |
| 1 | 09:11:44:110AM | Plasma | Ok | |
| 2 | 09:28:16:980AM | Plasma | Ok | |
| 3 | 09:40:53:973AM | Plasma | Ok | |
| 4 | 10:05:09:840AM | Plasma | Ok | |
| 5 | 11:01:00:923AM | Plasma | Ok | |
| 6 | 11:34:47:723AM | Plasma | Ok | |
| 7 | 12:00:52:133PM | Plasma | Ok | |
| 8 | 12:44:59:243PM | Plasma | Ok | |
| 9 | 01:45:16:390PM | Plasma | Ok | |
| 10 | 02:45:50:447PM | Plasma | Bad | Power Supply Problem |
| 11 | 03:25:31:603PM | Plasma | Ok | |
| 12 | 04:14:02:303PM | Test | Ok | TF Only PLC Test 100 KA |
| 13 | 04:59:08:740PM | Plasma | Ok | |