| Miniproposals | ||||||||||
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| Operators | |
| Session leader(s): | Jim Irby |
| Physics operator(s): | Ian Hutchinson |
| Engineering operator(s): | Bill Cochran,Gary Dekow,Frank Silva |
| Engineering Operator Run Comment |
| Reverse Field Start Up/ Hutch, Irby/ Silva, Dekow. Cochran |
| Session Leader Plans |
| Physics Operators Plans |
| Session Leader Summaries |
| Entered: Jul 7 2004 03:49:22:540PM |
| Author: To Be Determined |
| Physop Summary 000328 Restart Plasma operations. Establish Robust Startup with Abnormal Bt. Summary _______ Five plasmas were obtained. There were many technical difficulties. The machine was very dirty with high carbon levels. A leak developed about half way. Suggestions: Fix F-port leak. Run more plasmas to clean up. Things learned today. ____________________ There is probably a slight offset in the Bz in reversed field. It likes to go through Bz = 0 at about 5ms for a clean breakdown at that time, which implies that the true null is probably at Bz = 2 mT positive. For these rather dirty plasmas there seems to be some benefit to starting with a fairly slow Bz ramp, -5mT in 10ms for the first 10-12 ms. Then having a faster ramp (-15mT in 10ms) to get the field up quickly to the point it needs for equilibrium, if it is able to burn through the dirt. The easiest way to change the Bz ramp rate is with EF3 voltage. With it set at 2500V there is headroom for increasing or decreasing. E.g. 2800 gives a noticeable but quite controlable increase in ramp rate. Despite the very substantial bake and ECDC campaign, the carbon is still high. It appears (again) that these cleaning techniques do not remove carbon well. The later plasma behaviour is handicapped by continuous plasma fuelling despite the gas valve being closed. This leads to eventual disruption. The resistance is high. It is helpful in such a situation to reduce the gas puff. The OH2L coax resistance excursion was reversed by extending the fizzle detector to 0.5s. This allows the OHs to swing through zero, which they definitely like, from the viewpoint of keeping their resistance low. We probably need to separate the gas fizzle-detection from the coils, or else delay the coils being taken out by about 0.5s. A big 28 peak is a sign of a leaking seal. (No big surprise there.) Score Card __________ Shot,Duration(s),Ipmax(MA) Shot,Duration(s),Ipmax 1 0.000 0.016 2 0.000 0.014 3 0.000 0.021 4 0.000 0.029 5 0.135 0.532 6 0.000 0.013 7 0.000 0.021 8 0.000 0.034 9 0.156 0.543 10 0.000 0.024 11 0.199 0.628 12 0.000 0.027 13 0.000 0.027 14 0.305 0.737 15 0.000 0.024 16 0.000 0.024 17 0.000 0.023 18 0.000 0.024 19 0.000 0.021 20 0.000 0.023 21 0.314 0.748 22 0.000 0.020 23 0.000 0.024No Ip 24 25 0.000 0.003 26 0.000 0.003 27 0.000 0.021 Finished summary for 1000328 Total of 27 shots. 27 shots. 5 plasmas 2 duds, many tests, many fizzles. Details _______ Entry display output on Tue Mar 28 17:00:32 2000 ---------------------------------------------------------------------------- 1000328xxx hutch PHYSICS_OPERATOR Mar 28 2000 8:17:41:326AM . . . . . . . . . . . . . . . . . . . . Restart of Tokamak. Obtaining robust startup with abnormal field direction. Plan: 1 Get a plasma by tweaking the initiation. 2 Explore variations in field index and field ramp rate to optimize. Cold Start. Looks fine Start PCS. Load from 1000322005. Start with OH2 tests under PLC control. ---------------------------------------------------------------------------- 1000328001 hutch PHYSICS_OPERATOR Mar 28 2000 8:36:52:390AM . . . . . . . . . . . . . . . . . . . . OH Test at 10kA. Irby reports 0.9uOhms. ---------------------------------------------------------------------------- 1000328002 hutch PHYSICS_OPERATOR Mar 28 2000 8:46:12:170AM . . . . . . . . . . . . . . . . . . . . OH test 1.27uOhm. ---------------------------------------------------------------------------- 1000328003 hutch PHYSICS_OPERATOR Mar 28 2000 8:51:27:060AM . . . . . . . . . . . . . . . . . . . . OH test with different timing of OH wrt TF. 1.5uOhm. Copy pulse gas 3 trace into pulse gas 5 (J-bottom). ---------------------------------------------------------------------------- 1000328004 hutch PHYSICS_OPERATOR Mar 28 2000 9:23:24:623AM . . . . . . . . . . . . . . . . . . . . Try for plasma. Fizzle. Breakdown at .9ms because Bz is too positive. This is very similar to the shot 5 that we loaded. OH2 1.8uOhm. Need to lower Bz by about 5mT. ICEF4 is at +1390. Calibration is about 15A per mT on EF4. So we need to take 75A off EF4. and set to 1315A. ---------------------------------------------------------------------------- 1000328005 hutch PHYSICS_OPERATOR Mar 28 2000 10:12:27:640AM . . . . . . . . . . . . . . . . . . . . Plasma till about .13s then lots of radiation and disrupts from about 500kA. OH2 2.04uOhm. Breakdown at .49ms but Plasma current has a big hesitation during which it moves inside. Looks as if the Bz is not ramping fast enough during the first 15ms. Stop to mess with the OH2 joint. Set EF3 Voltage to -2800V during first 10ms from old value of ~-2500. ---------------------------------------------------------------------------- 1000328006 hutch PHYSICS_OPERATOR Mar 28 2000 11:00:25:233AM . . . . . . . . . . . . . . . . . . . . OH test 1.5uOhm. Delay fizzle detector to 0.5s. The idea is to let the OH swing in the expectation that that helps the joint. ---------------------------------------------------------------------------- 1000328007 hutch PHYSICS_OPERATOR Mar 28 2000 11:23:05:890AM . . . . . . . . . . . . . . . . . . . . Fizzle. CII is way up .02. OH 1.48uOhm. Seemed to get slightly faster EF3 ramp. Mflux shows the difference. Only 20kA current. EF3 back to 2500. ---------------------------------------------------------------------------- 1000328008 hutch PHYSICS_OPERATOR Mar 28 2000 11:39:04:750AM . . . . . . . . . . . . . . . . . . . . Fizzle bounces at 30kA at 15ms. Bz is clearly under control by EF3. EF4 to 1300A. EF3 V to 2500 at 12ms (from 2000). ---------------------------------------------------------------------------- 1000328009 hutch PHYSICS_OPERATOR Mar 28 2000 11:57:34:030AM . . . . . . . . . . . . . . . . . . . . Plasma till 1.55s. Similar to shot 5. 0.98uOhm. nl04 to .5e20 at 200ms, a slight reduction in the requested density ramp rate in segment 2. ---------------------------------------------------------------------------- 1000328010 hutch PHYSICS_OPERATOR Mar 28 2000 12:14:32:966PM . . . . . . . . . . . . . . . . . . . . Fizzle. Only 20kA. Did not bounce. CII .018 No changes. ---------------------------------------------------------------------------- 1000328011 hutch PHYSICS_OPERATOR Mar 28 2000 12:40:47:793PM . . . . . . . . . . . . . . . . . . . . Plasma till .2s. Br offset to -.0005 from -.001. nl04 to .4e20 at 200ms. Start chopper ramp at 40ms instead of 48ms. ---------------------------------------------------------------------------- 1000328012 hutch PHYSICS_OPERATOR Mar 28 2000 12:50:09:060PM . . . . . . . . . . . . . . . . . . . . Fizzle. CII back to .019. However, the Br became more negative, contrary to expectations. OH 0.61uOhm. Br offset to -.0015. ---------------------------------------------------------------------------- 1000328013 hutch PHYSICS_OPERATOR Mar 28 2000 1:04:58:170PM . . . . . . . . . . . . . . . . . . . . Fizzle. Br went much more negative. I did move it in the right direction before. But there was clearly some offset drift. The null is clearly very bad in this case. Set Br offset to 0. ---------------------------------------------------------------------------- 1000328014 hutch PHYSICS_OPERATOR Mar 28 2000 1:20:50:826PM . . . . . . . . . . . . . . . . . . . . Plasma till .3s. CII .013. Br decent. Lower Pulse Gas 3 V program during .05 to .1s. ---------------------------------------------------------------------------- 1000328015 hutch PHYSICS_OPERATOR Mar 28 2000 1:37:41:233PM . . . . . . . . . . . . . . . . . . . . Fizzle. Strange result on the F-side pressure. Goes up at the flash. Br offset to +.0005mT EF4 to 1290A. ---------------------------------------------------------------------------- 1000328016 hutch PHYSICS_OPERATOR Mar 28 2000 1:54:00:466PM . . . . . . . . . . . . . . . . . . . . Fizzle. CII above .02, Z-meter very high. Breakdown at 5.4ms EF4 to 1280. Chopper ramp start to 35ms. ---------------------------------------------------------------------------- 1000328017 hutch PHYSICS_OPERATOR Mar 28 2000 2:14:50:186PM . . . . . . . . . . . . . . . . . . . . Fizzle. Breakdown at 7ms. CII still over .02. Br offset to 0. ---------------------------------------------------------------------------- 1000328018 hutch PHYSICS_OPERATOR Mar 28 2000 2:31:10:513PM . . . . . . . . . . . . . . . . . . . . Fizzle still a late breakdown. CII over .02. EF4 to 1260A. ---------------------------------------------------------------------------- 1000328019 hutch PHYSICS_OPERATOR Mar 28 2000 2:43:18:950PM . . . . . . . . . . . . . . . . . . . . Dud. EF4 to 1300. ---------------------------------------------------------------------------- 1000328020 hutch PHYSICS_OPERATOR Mar 28 2000 3:01:19:356PM . . . . . . . . . . . . . . . . . . . . Fizzle. Breakdown is now back at 5ms. CII is .025! Gas to 21ms prepuff, was 24. ---------------------------------------------------------------------------- 1000328021 hutch PHYSICS_OPERATOR Mar 28 2000 3:13:50:436PM . . . . . . . . . . . . . . . . . . . . Plasma till .31s Big hesitation. Hard xrays. CII just below .02. Change nothing. ---------------------------------------------------------------------------- 1000328022 hutch PHYSICS_OPERATOR Mar 28 2000 3:36:27:233PM . . . . . . . . . . . . . . . . . . . . Dud. The Bz had drifted down slightly. EF4 to 1310. ---------------------------------------------------------------------------- 1000328023 hutch PHYSICS_OPERATOR Mar 28 2000 4:48:10:153PM . . . . . . . . . . . . . . . . . . . . Fizzle. CII is .025 Cell access to try purging the F-port seal to check if the event that came on shot 14 is a leak. Also various other diagnostic matters. The RGA is showing a big 28 peak, a significant fraction of the base pressure of 3.8e-7, the 14 is at about 5% of the 28, which is the right level for Nitrogen. Purging F-port seal converts 28 into 40. We establish that it was a leak. Try with the seal purging with Argon. As we try to restart all sort of sequencing and scanner problems occur. ---------------------------------------------------------------------------- 1000328026 hutch PHYSICS_OPERATOR Mar 28 2000 4:48:32:793PM . . . . . . . . . . . . . . . . . . . . Cycle to try to clear out the bugs. ---------------------------------------------------------------------------- 1000328027 hutch PHYSICS_OPERATOR Mar 28 2000 4:59:55:186PM . . . . . . . . . . . . . . . . . . . . Fizzle. |
| Physics Operator Summaries |
| Session Leader Comments |
| Physics Operator Comments | |||
| Mar 28 2000 08:17:41:327AM | Ian Hutchinson | Restart of Tokamak. Obtaining robust startup with abnormal field direction. Plan: 1 Get a plasma by tweaking the initiation. 2 Explore variations in field index and field ramp rate to optimize. Cold Start. Looks fine Start PCS. Load from 1000322005. Start with OH2 tests under PLC control. | |
| Mar 28 2000 08:36:52:390AM | 1000328001 | Ian Hutchinson | OH Test at 10kA. Irby reports 0.9uOhms. |
| Mar 28 2000 08:46:12:170AM | 1000328002 | Ian Hutchinson | OH test 1.27uOhm. |
| Mar 28 2000 08:51:27:060AM | 1000328003 | Ian Hutchinson | OH test with different timing of OH wrt TF. 1.5uOhm. Copy pulse gas 3 trace into pulse gas 5 (J-bottom). |
| Mar 28 2000 09:23:24:623AM | 1000328004 | Ian Hutchinson | Try for plasma. Fizzle. Breakdown at .9ms because Bz is too positive. This is very similar to the shot 5 that we loaded. OH2 1.8uOhm. Need to lower Bz by about 5mT. ICEF4 is at +1390. Calibration is about 15A per mT on EF4. So we need to take 75A off EF4. and set to 1315A. |
| Mar 28 2000 10:12:27:640AM | 1000328005 | Ian Hutchinson | Plasma till about .13s then lots of radiation and disrupts from about 500kA. OH2 2.04uOhm. Breakdown at .49ms but Plasma current has a big hesitation during which it moves inside. Looks as if the Bz is not ramping fast enough during the first 15ms. Stop to mess with the OH2 joint. Set EF3 Voltage to -2800V during first 10ms from old value of ~-2500. |
| Mar 28 2000 11:00:25:233AM | 1000328006 | Ian Hutchinson | OH test 1.5uOhm. Delay fizzle detector to 0.5s. The idea is to let the OH swing in the expectation that that helps the joint. |
| Mar 28 2000 11:23:05:890AM | 1000328007 | Ian Hutchinson | Fizzle. CII is way up .02. OH 1.48uOhm. Seemed to get slightly faster EF3 ramp. Mflux shows the difference. Only 20kA current. EF3 back to 2500. |
| Mar 28 2000 11:39:04:750AM | 1000328008 | Ian Hutchinson | Fizzle bounces at 30kA at 15ms. Bz is clearly under control by EF3. EF4 to 1300A. EF3 V to 2500 at 12ms (from 2000). |
| Mar 28 2000 11:57:34:030AM | 1000328009 | Ian Hutchinson | Plasma till 1.55s. Similar to shot 5. 0.98uOhm. nl04 to .5e20 at 200ms, a slight reduction in the requested density ramp rate in segment 2. |
| Mar 28 2000 12:14:32:967PM | 1000328010 | Ian Hutchinson | Fizzle. Only 20kA. Did not bounce. CII .018 No changes. |
| Mar 28 2000 12:40:47:793PM | 1000328011 | Ian Hutchinson | Plasma till .2s. Br offset to -.0005 from -.001. nl04 to .4e20 at 200ms. Start chopper ramp at 40ms instead of 48ms. |
| Mar 28 2000 12:50:09:060PM | 1000328012 | Ian Hutchinson | Fizzle. CII back to .019. However, the Br became more negative, contrary to expectations. OH 0.61uOhm. Br offset to -.0015. |
| Mar 28 2000 01:04:58:170PM | 1000328013 | Ian Hutchinson | Fizzle. Br went much more negative. I did move it in the right direction before. But there was clearly some offset drift. The null is clearly very bad in this case. Set Br offset to 0. |
| Mar 28 2000 01:20:50:827PM | 1000328014 | Ian Hutchinson | Plasma till .3s. CII .013. Br decent. Lower Pulse Gas 3 V program during .05 to .1s. |
| Mar 28 2000 01:37:41:233PM | 1000328015 | Ian Hutchinson | Fizzle. Strange result on the F-side pressure. Goes up at the flash. Br offset to +.0005mT EF4 to 1290A. |
| Mar 28 2000 01:54:00:467PM | 1000328016 | Ian Hutchinson | Fizzle. CII above .02, Z-meter very high. Breakdown at 5.4ms EF4 to 1280. Chopper ramp start to 35ms. |
| Mar 28 2000 02:14:50:187PM | 1000328017 | Ian Hutchinson | Fizzle. Breakdown at 7ms. CII still over .02. Br offset to 0. |
| Mar 28 2000 02:31:10:513PM | 1000328018 | Ian Hutchinson | Fizzle still a late breakdown. CII over .02. EF4 to 1260A. |
| Mar 28 2000 02:43:18:950PM | 1000328019 | Ian Hutchinson | Dud. EF4 to 1300. |
| Mar 28 2000 03:01:19:357PM | 1000328020 | Ian Hutchinson | Fizzle. Breakdown is now back at 5ms. CII is .025! Gas to 21ms prepuff, was 24. |
| Mar 28 2000 03:13:50:437PM | 1000328021 | Ian Hutchinson | Plasma till .31s Big hesitation. Hard xrays. CII just below .02. Change nothing. |
| Mar 28 2000 03:36:27:233PM | 1000328022 | Ian Hutchinson | Dud. The Bz had drifted down slightly. EF4 to 1310. |
| Mar 28 2000 04:48:10:153PM | 1000328023 | Ian Hutchinson | Fizzle. CII is .025 Cell access to try purging the F-port seal to check if the event that came on shot 14 is a leak. Also various other diagnostic matters. The RGA is showing a big 28 peak, a significant fraction of the base pressure of 3.8e-7, the 14 is at about 5% of the 28, which is the right level for Nitrogen. Purging F-port seal converts 28 into 40. We establish that it was a leak. Try with the seal purging with Argon. As we try to restart all sort of sequencing and scanner problems occur. |
| Mar 28 2000 04:48:32:793PM | 1000328026 | Ian Hutchinson | Cycle to try to clear out the bugs. |
| Mar 28 2000 04:59:55:187PM | 1000328027 | Ian Hutchinson | Fizzle. |
| Engineering Operator Comments | ||||
| Shot | Time | Type | Status | Comment |
| 1 | 08:22:16:670AM | Test | Ok | OH1,2u,l rev. bridge&TF test |
| 2 | 08:32:36:060AM | Test | Ok | Same as shot #1 |
| 3 | 08:46:47:280AM | Test | Ok | Same as 1,&2 Test OK |
| 4 | 09:10:18:623AM | Plasma | Ok | no faults / fizzle |
| 5 | 09:25:30:403AM | Plasma | Ok | no faults/fizzle |
| 6 | 10:53:04:403AM | Test | Ok | OH1,2u,l with TF at 150 KA |
| 7 | 11:06:33:293AM | Plasma | Ok | no faults/fizzle |
| 8 | 11:22:40:373AM | Plasma | Ok | no faults/fizzel |
| 9 | 11:37:38:513AM | Plasma | Ok | no faults/plasma |
| 10 | 11:55:54:983AM | Plasma | Ok | no faults/fizzel |
| 11 | 12:12:58:590PM | Plasma | Ok | |
| 12 | 12:33:23:357PM | Plasma | Ok | |
| 13 | 12:48:43:500PM | Plasma | Ok | |
| 14 | 01:02:59:123PM | Plasma | Ok | |
| 15 | 01:19:18:827PM | Plasma | Ok | |
| 16 | 01:33:04:560PM | Plasma | Ok | |
| 17 | 01:52:18:107PM | Plasma | Ok | |
| 18 | 02:10:46:233PM | Plasma | Ok | |
| 19 | 02:27:51:467PM | Plasma | Ok | |
| 20 | 02:43:33:420PM | Plasma | Ok | |
| 21 | 02:58:58:310PM | Plasma | Ok | |
| 22 | 03:18:01:357PM | Plasma | Ok | |
| 23 | 03:33:40:840PM | Plasma | Ok | |
| 24 | 04:11:24:280PM | Plasma | Bad | State Ack. Failure |
| 25 | 04:20:02:607PM | Test | Ok | Camac Cycle Test |
| 26 | 04:31:11:013PM | Test | Ok | |
| 27 | 04:56:52:327PM | Plasma | Ok | No Faults |