| Miniproposals | ||||||||||
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| Operators | |
| Session leader(s): | Martin Greenwald |
| Physics operator(s): | Ian Hutchinson |
| Engineering operator(s): | Vinny Bertolino |
| Engineering Operator Run Comment |
| hutch |
| Session Leader Plans |
| Physics Operators Plans |
| Session Leader Summaries |
| Entered: Jul 7 2004 03:49:13:880PM |
| Author: To Be Determined |
Shot sequence plan 1. scan kappa from 0.9 to 1.5 at Ip = .5 MA, ne = 0.5 x 1020 - limited 2. scan kappa from 0.9 to 1.5 at Ip = .5 MA, ne = 1.5 x 1020 - limited 3. scan kappa from 0.9 to 1.5 at q95 = 4, (Ip ~ .45 to .8 MA) ne = 0.5 x 1020 - limited 4. scan kappa from 0.9 to 1.5 at q95 = 4, (Ip ~ .45 to .8 MA) ne = 1.5 x 1020 - limited (Assuming ~5 kappa's for each these scans, kappa = [.9, 1.0, 1.1, 1.3, 1.5] => 20 good shots) Run Summary for 950606 - ohmic confinement, kappa scan ------------------------------------------------------ Objective: Test possible explanations for the observed difference in confinement scaling between C-Mod and Alcator C. This run will focus on effects of plasma shaping. Plan: a. scan kappa for otherwise identical discharges. - this should be done at two densities, the first at the lowest feasible density to explore the "neo-Alcator" regime (nebar = .5e20 if possible), the second at a higher density where we have previously seen no density dependence (nebar = 1.5e20). b. scan kappa at fixed q - use the same two densities Toroidal Field: 5.3 Plasma Current: 0.4-0.8 MA Working gas species: D2 Results: The run went pretty well considering the unusual requirements. Getting low density was difficult due to impurity and radiation problems and (maybe) to the highly non-linear nature of the pulsed gas valve at low flow rates. Of 38 total shots 25 may be suitable for analysis. for the constant Ip = .5 scans Shot nebar kappa 950606003 .75-1. 1.15 950606006 .55-.7 1.15 950606007 .45-.75 1.15 950606008 .4-.5 1.15 950606009 .5 1.04 950606010 .5 0.98 950606011 .5 0.98 950606012 .5-.65 0.95 950606013 .5-.65 0.95 950606014 .4-.5 1.4 950606015 .6-.8 1.4 950606016 .6-.9 1.4 950606017 .5-.7 1.4 950606018 .5-.7 1.2 950606019 1.4-1.7 1.2 950606021 1.4 1.2 950606022 1.4 1.1 950606023 1.4 1.03 950606024 1.3-1.4 0.95 950606025 1.3-1.4 0.95 950606026 1.3-1.4 1.4 for the constant q = 4 scan shot nebar kappa ip 950606030 .7 1.4 .76 950606035 .7-.8 1.4 .75 950606036 .8 1.2 .63 950606038 .55 1.03 .51 |
| Physics Operator Summaries |
| Entered: Jul 7 2004 04:36:54:677PM |
| Author: To Be Determined |
| 950606 Kappa Scan from .9 to 1.5. SL Greenwald PO Hutch EO Bertolino Do a controlled low density kappa scan to investigate the kappa dependence of tauE and try to figure out the absence of NeoAlcator scaling. Summary _______ The kappa estimator/controller works but has offset and calibration problems. With the present reference, asking for 1.2 gave nearly 1.4, asking for 1.1 gave nearly 1.2, and there seemed to be an offset of about .05 near kappa=1. It was generally rather difficult to run with n_bar less than 0.6e20 but we did so on a number of shots. Bright runaway light was seen on the TV and looks like synchrotorn radiation. At any rate it is tangential beaming. The controlled kappa scans at density of n_bar=.5 and 1.5 e20 were done. Low density has very high radiation and zeff. The radiation drops as kappa is increased. Input power (i.e. loop voltage) also drops, implying a strong rise of tauE with kappa at low density. A kappa scan at constant safety factor at low density was also accomplished. Time did not permit the constant q scan at higher density. Scorecard: _________ Shot,Duration(s),Ipmax(MA) Shot,Duration(s),Ipmax 1 0.000 0.018 2 0.000 0.037 3 1.477 0.530 4 0.597 0.523 5 0.000 0.008 6 1.479 0.530 7 1.477 0.523 8 1.480 0.512 9 1.474 0.502 10 1.462 0.505 11 0.599 0.541 12 1.473 0.499 13 1.470 0.505 14 1.490 0.538 15 1.487 0.541 16 1.491 0.549 17 1.489 0.538 18 1.481 0.528 19 1.109 0.533 20 0.000 0.024 21 1.482 0.538 22 1.481 0.538 23 1.474 0.533 24 1.477 0.530 25 1.474 0.525 26 1.478 0.564 27 0.377 0.549 28 1.494 0.533 29 1.469 0.538 30 1.100 0.780 31 0.440 0.830 32 0.449 0.830 33 0.576 0.828 34 0.000 0.029 35 1.029 0.815 36 1.486 0.642 *** Consider increasing shotmax. 36 Finished summary for 950606 Total of 36 shots. 36 shots. 31 plasmas. 3 fizzles. 2 duds. Details _______ Load segment2 from 950516006. Kappa reference is 1. (ztop=.23,zbot=-.23m) Move zxl and zxu out by 5 cm to reduce triangularity. Lower nl04 to 4e20. (Remember the important L changes this run.) Fill at 2.0e-5. 1 PS test. Coldstart Ok 2 Fiz 40 kA bounce. Raise fill to 2.4 3 Ran to 1.5 s. EF4 is close to zero so crossover is a problem. Raise gain on zxu,zxl to 5=20s^-1. Lower Ip fractionally to 500kA and raise its early gain Lower nl04 to ramp from 3. to 1.5e19. 4 Disrupts at .6 sec. Power supply problems. OH2L trips at .18s and pulls all PFs shortly thereafter. Plasma ramps down surprisingly well. Remove the step up in the pulse gas 3 V at near .2s that seems to be giving an extra puff. 5 PS dud Hardly any power supplies. Type 3 fault from cryo. Raise derivative on RCUR in segment 1 to 9 from 6 V/V. 6 Went till 1.5s. Some TV speckles at the end. kappa 1.1 with a slight down ramp to 1 at OH1 cross-over .5s. Density still a little high. Move zxl,u to .06 tried .08 but overflowed. add argon puff, 23ms at 120ms. lower nl04 at .22s. add gas puf at the end using nl04 for hards. 7 No speckles. EF4 stays positive after its cross-over. Still n too high. Lower nl04 to .2, lower gas3 V during .1-.9s. Shorten Argon puff to 15ms because Rice has too much signal. Lower EF2byEf4 gain to 1. 8 Lower density obtained. Bright central region on TV speckles etc. RAther a lot of hards there. Raised end gas to nl04=6. Installed an upramp .2 to .3 nl04. Installed integral gain on kappa at .5 V/V this makes PI=20,20 s^-1(2) Set kappa to -.1. 9 Still a bright plasma center. But the end gas puff stops it. Got kappa of about .96 consistent with the kappa error of 30000. Plasma very resistive early nearly dies at .2s. Raise integral gain to 2. 10 Rather more non-thermal. Clear asymmetric central radiation on the wide angle TV. Synchrotron? Raise kappa gain to 7., set to -.15 Raise nl04 to .35 at 1s. 11 Disrupts at .58s. EF3/OH2 showing signs of instability. RCUR instability is evident. Kappa get below .9. Lowered kappa gain back to 5. Increased RCUR P to 9.5 from 6. Added wire 10 with D gain of .5 which is equivalent to 5 on wire 1. So total D is of order .15 physics. 12 Survived, but higher frequency oscillation. Around 50 Hz. Got kappa of .87 at .5s. YAG did not go. Repeat 13 OK. Discovered that the late density drop is due to gas3 V-program. Fixed. Set kappa to (1+).2. Kappa gain to .7 14 Got Kappa of 1.4. There seems to be a calibration problem. Phys-A-Out shows we are following the controller well; so this is a predictor calibration issue. We could recalculate, but not now. This is a very low density because of geometry. lower gas puff 3 to 25V during .05 to .1s. increase nl04 to 2.8 ramping to 5.2 15 Got .34e20 rather too high, Ramp is OK. Raised PG3 at .1 to .2s to try to keep the density near the right value so we don't over puff later. 16 Did not work to lower the density. Lower PG3 V during .2 to .5s. Lower nl04 to .25. 17 Got .27e20 at .4s ramping to .5. OK for the data. Set kappa 1.1. Lower nl04 to .23 ramping to .45. 18 OK. got .27e20 ramping. Got kappa about 1.2 Start higher density kappa-scan. Set nl04 to .7-1.3e20. Raise segment 1 PG3 to 25-30V. 19 Got resistive at the end. Disrupts at 1s. Current sags. Raise Ip gain to 9 from 6. Raise OH Vs to 170V(OH1) and 20V(OH2) Remove most of the density ramp. 20 Fiz EF4 to -1090 from -1100. Fill to 2.0e-5. 21 Ran to 1.5s. got kappa of 1.2. Lower kappa to 1.0. Lower nl04 to .58 22 Got nl04=.58. kappa 1.05 (mfil) (1.1 EFIT). Lower kappa to .95. nl04 to .55. 23 Got nl04 5.4 to 6.3. q=4 after cross-over. kappa .98 (Efit kappa 1.03) Lower kappa to .88. nl04 to .52 24 Slight Oh1 oscillations. kappa =.92 nl=.51. kappa to .84. Argon was to have been off but the gremlins got us. 25 kappa .89. looks as if I forgot to load. kappa to 1.2, nl to .8. Shorten Argon to 12 ms. 26 Got kappa=1.42, nl=.83to .9e20. Argon was nearly a factor 12 less. Radiation is much reduced. This is the argon off test. It looks like argon is important. Reset Argon to 18ms but set its pressure to 2 psi from 4. 27 Disrupt at .38s due to density feedback running wild. Fuels to the Greenwald limit. Limited plasma. Repeat. 28 Runaways later. Density feedback borke again and turned off the gas. Low density. Repeat. 29 nl=.85e20 at last. Start Constant-q scan. Raise Ip to .75MA, nl04 to .28-.32e19. 30 EF2s remain high throughout. disrupts at 1.07s apparently too much gas puff at the end. Got kappa=1.36. nl04=.38 to .43e20. Lower nl04 puff at the end and PG3 throughout. 31 Disrupts at .44 sec. Might be the EF2s coming out of saturation. Not a VDE. Density just too low. Restore some of the early PG3 voltage. 32 Same sort of thing. Set nl04 to be at .27 from about .15s. Turned the kappa into a ramp from 0. to .4s to help Ef2s. 33 Disrupts at .5s. A little extra density gets it further. Set nl04 to .4 at .4s. Then allow to droop. 34 Fiz 32kA at 14ms. late breakdown 7ms. Raise fill pressure to 2.2. 35 OK but density stays about .4e20. Disrupts at 1s. Lower kappa to 1.1 demand (1.2 equiv). Lower current to .62MA. NL04 to .35 at .4s. 36 Got kappa of 1.18, nl04 of .36. Lower nl04 to about .23 and ease off the ramp-dwonw gas puff. Lower Ip to .5 Lower kappa to .95. 37 Disrupts at .33s. Very resistive and low density. Top up plenum to 20 from 18psi. Raise .26s nl04 to nearly .3. 38 Nice shot. NL04=.24 |
| Session Leader Comments | |||
| Jun 6 1995 08:27:47:500AM | Martin Greenwald | Test possible explanations for the observed difference in confinement scaling
between C-Mod and Alcator C. This run will focus on effects of plasma shaping. The scans we need to do are: a. scan kappa for otherwise identical discharges. - this should be done at two densities, the first at the lowest feasible density to explore the "neo-Alcator" regime (nebar = .5e20 if possible), the second at a higher density where we have previously seen no density dependence (nebar = 1.5e20). b. scan kappa at fixed q - use the same two densities Toroidal Field: 5.3 Plasma Current: 0.4-0.8 MA Working gas species: D2 Shot sequence plan 1. scan kappa from 0.9 to 1.5 at Ip = .5 MA, ne = 0.5 x 1020 - limited 2. scan kappa from 0.9 to 1.5 at Ip = .5 MA, ne = 1.5 x 1020 - limited 3. scan kappa from 0.9 to 1.5 at q95 = 4, (Ip ~ .45 to .8 MA) ne = 0.5 x 1020 - limited 4. scan kappa from 0.9 to 1.5 at q95 = 4, (Ip ~ .45 to .8 MA) ne = 1.5 x 1020 - limited (Assuming ~5 kappa's for each these scans, kappa = [.9, 1.0, 1.1, 1.3, 1.5] => 20 good shots) | |
| Jun 6 1995 08:56:27:350AM | 950606002 | Martin Greenwald | fizzle
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| Jun 6 1995 08:55:29:680AM | 950606003 | Martin Greenwald | Good shot
Ip = .51 a = .225 kappa = 1.15 nebar_07 = 1 -> .75 (ramping down) |
| Jun 6 1995 09:04:54:920AM | 950606003 | Martin Greenwald | power supply problem - short shot
|
| Jun 6 1995 09:05:10:150AM | 950606004 | Martin Greenwald | power supply problem - short shot
|
| Jun 6 1995 09:21:11:260AM | 950606005 | Martin Greenwald | power supply problem - no shot
|
| Jun 6 1995 09:31:46:530AM | 950606006 | Martin Greenwald | Good shot
Ip = .5 a = .225 kappa = 1.15 nebar_07 = .7 -> .55 (ramping down) |
| Jun 6 1995 09:51:03:220AM | 950606007 | Martin Greenwald | Good shot
Ip = .5 a = .225 kappa = 1.15 nebar_07 = .75 -> .45 (ramping down) |
| Jun 6 1995 10:06:36:450AM | 950606008 | Martin Greenwald | Good shot
Ip = .5 a = .225 kappa = 1.15 nebar_07 = .5 -> .4 (ramping down) |
| Jun 6 1995 10:23:14:830AM | 950606009 | Martin Greenwald | Good shot
Ip = .5 a = .225 kappa = 1.04 nebar_07 = .5 (ramping down) |
| Jun 6 1995 10:47:27:840AM | 950606010 | Martin Greenwald | Good shot
Ip = .5 a = .225 kappa = .98 nebar_07 = .5 |
| Jun 6 1995 10:46:23:860AM | 950606011 | Martin Greenwald | Good shot
Ip = .5 a = .225 kappa = .98 nebar_07 = .5 |
| Jun 6 1995 11:00:13:460AM | 950606011 | Martin Greenwald | Disrupts - radial instability
|
| Jun 6 1995 11:12:55:660AM | 950606012 | Martin Greenwald | Good shot
Ip = .51 a = .225 kappa = .95 nebar_07 = .5 -> .65 (ramping down) |
| Jun 6 1995 11:24:20:740AM | 950606013 | Martin Greenwald | Good shot
Ip = .51 a = .225 kappa = .95 nebar_07 = .5 -> .65 (ramping down) |
| Jun 6 1995 11:36:37:040AM | 950606014 | Martin Greenwald | kappa higher than expected (1.4 instead of 1.2) so density too low
a bit disruptive besides |
| Jun 6 1995 11:49:35:700AM | 950606015 | Martin Greenwald | Good shot but density a bit too high.
kappa = 1.4 |
| Jun 6 1995 12:28:01:940PM | 950606016 | Martin Greenwald | Good shot - but density still a bit high
nebar_07 = .6 ->.9 ramp up kappa = 1.4 |
| Jun 6 1995 12:26:42:720PM | 950606017 | Martin Greenwald | Good shot
nebar_07 = .5 ->.7 ramp up kappa = 1.4 |
| Jun 6 1995 12:42:48:390PM | 950606018 | Martin Greenwald | Good shot
nebar_07 = .5 ->.7 ramp up kappa = 1.2 |
| Jun 6 1995 12:51:58:210PM | 950606019 | Martin Greenwald | Good shot
nebar_07 = 1.4 ->1.7 ramp up kappa = 1.2 |
| Jun 6 1995 12:54:32:010PM | 950606020 | Martin Greenwald | fizzle
|
| Jun 6 1995 01:14:31:990PM | 950606021 | Martin Greenwald | Good shot
nebar 07 = 1.4 kappa = 1.2 |
| Jun 6 1995 01:27:42:840PM | 950606022 | Martin Greenwald | Good shot
nebar 07 = 1.4 kappa = 1.1 |
| Jun 6 1995 01:51:57:450PM | 950606023 | Martin Greenwald | Good shot
nebar 07 = 1.4 kappa = 1.03 |
| Jun 6 1995 01:57:31:360PM | 950606024 | Martin Greenwald | Good shot
nebar 07 = 1.3 - 1.4 kappa = .95 |
| Jun 6 1995 02:09:49:030PM | 950606025 | Martin Greenwald | Good shot
nebar 07 = 1.3 - 1.4 kappa = .95 |
| Jun 6 1995 02:26:51:800PM | 950606026 | Martin Greenwald | Good shot
nebar 07 = 1.3 - 1.4 kappa = 1.4 |
| Jun 6 1995 02:39:23:900PM | 950606027 | Martin Greenwald | Disrupted - runaway gas puff
|
| Jun 6 1995 02:57:58:250PM | 950606028 | Martin Greenwald | no density trace - very low
|
| Jun 6 1995 03:20:46:720PM | 950606030 | Martin Greenwald | first shot of constant q scan
ip = .76 q95 = 4 nebar = .7 |
| Jun 6 1995 03:28:25:270PM | 950606031 | Martin Greenwald | early disruption
|
| Jun 6 1995 03:39:53:010PM | 950606032 | Martin Greenwald | early disruption
|
| Jun 6 1995 03:53:02:920PM | 950606033 | Martin Greenwald | early disruption
|
| Jun 6 1995 03:56:06:130PM | 950606033 | Martin Greenwald | early disruption
some analysis might be possible nebar 07 = .5 .7 ip = .76 q95 = 4.3 |
| Jun 6 1995 04:09:39:770PM | 950606034 | Martin Greenwald | fizzle
|
| Jun 6 1995 04:36:13:360PM | 950606034 | Martin Greenwald | early disruption
some analysis might be possible nebar 07 = .5 .7 ip = .76 q95 = 4.3 |
| Jun 6 1995 04:18:22:050PM | 950606035 | Martin Greenwald | nebar = .8
kappa = 1.4 ip = .76 |
| Jun 6 1995 04:35:52:270PM | 950606035 | Martin Greenwald | nebar = .7 - .8
kappa = 1.2 ip = .75 q = 4.3 |
| Jun 6 1995 04:34:35:000PM | 950606036 | Martin Greenwald | nebar = .8
kappa = 1.2 ip = .63 q = 4 |
| Jun 6 1995 04:42:06:780PM | 950606037 | Martin Greenwald | disrupts early
|
| Jun 6 1995 04:57:40:890PM | 950606038 | Martin Greenwald | Ip = .51
q95 = 4 nebar 07 = .55 kappa = 1.03 |
| Physics Operator Comments |
| Engineering Operator Comments | ||||
| Shot | Time | Type | Status | Comment |
| 1 | 08:23:00:870AM | Test | Ok | coax test |
| 2 | 08:32:25:640AM | Plasma | Ok | |
| 3 | 08:43:09:870AM | Plasma | Ok | |
| 4 | 08:57:56:590AM | Plasma | Bad | oh2l comm fault |
| 5 | 09:12:45:440AM | Plasma | Bad | mag resist type 3 |
| 6 | 09:22:58:620AM | Plasma | Ok | |
| 7 | 09:42:58:680AM | Plasma | Ok | |
| 8 | 09:57:03:010AM | Plasma | Ok | |
| 9 | 10:14:59:110AM | Plasma | Ok | |
| 10 | 10:30:15:170AM | Plasma | Ok | |
| 11 | 10:45:00:710AM | Plasma | Ok | |
| 12 | 11:02:05:590AM | Plasma | Ok | |
| 13 | 11:14:41:200AM | Plasma | Ok | |
| 14 | 11:26:55:810AM | Plasma | Ok | |
| 15 | 11:41:23:670AM | Plasma | Ok | |
| 16 | 11:57:30:040AM | Plasma | Ok | |
| 17 | 12:11:30:980PM | Plasma | Ok | |
| 18 | 12:24:29:060PM | Plasma | Ok | |
| 19 | 12:40:38:320PM | Plasma | Ok | |
| 20 | 12:52:19:240PM | Plasma | Ok | |
| 21 | 01:06:19:070PM | Plasma | Ok | |
| 22 | 01:21:24:330PM | Plasma | Ok | |
| 23 | 01:35:04:620PM | Plasma | Ok | |
| 24 | 01:50:11:150PM | Plasma | Ok | |
| 25 | 02:02:35:330PM | Plasma | Ok | |
| 26 | 02:17:36:160PM | Plasma | Ok | |
| 27 | 02:35:12:420PM | Plasma | Ok | |
| 28 | 02:46:16:910PM | Plasma | Ok | |
| 29 | 03:00:12:070PM | Plasma | Ok | |
| 30 | 03:12:28:340PM | Plasma | Ok | |
| 31 | 03:24:04:930PM | Plasma | Ok | |
| 32 | 03:35:40:670PM | Plasma | Ok | |
| 33 | 03:47:13:170PM | Plasma | Ok | |
| 34 | 04:01:57:070PM | Plasma | Ok | |
| 35 | 04:10:46:020PM | Plasma | Ok | |
| 36 | 04:26:58:120PM | Plasma | Ok | |
| 37 | 04:39:04:010PM | Plasma | Ok | |
| 38 | 04:50:22:940PM | Plasma | Ok | |