| Miniproposals | ||||||||||||
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| Operators | |
| Session leader(s): | Michael Graf,Jim Terry |
| Physics operator(s): | Earl Marmar |
| Engineering operator(s): | Vinny Bertolino |
| Engineering Operator Run Comment |
| laser ablation |
| Session Leader Plans |
| Physics Operators Plans |
| Session Leader Summaries |
| Entered: Jul 7 2004 03:49:09:290PM |
| Author: To Be Determined |
| Run summary for 931019. Session leaders: Graf/Terry Physics operator: Marmar Objectives: Observe impurity transport (injected via laser blow-off) while performing various parameter scans (esp. current, density, background gas). Shots 4-13 constituted a current scan at roughly fixed density (about nl=6e19). Shots 14-23 constituted a density scan at roughly fixed current (about 850 kA). Shots 25-28 constituted a change in background gas mass scan with Helium being puffed through the divertor. 001 good shot, 900 kA, no scheduled injections, natual Mo at .43 002 OK shot, 950 kA, scheduled injection of Sc at .55, disruption at .55 (not initiated by Sc injection--yeah, right) 003 good shot, 870 kA, no Sc injection, lots of nat'l iron though 004 good shot, 890 kA, Sc injection at .55, nl=6.3e19 at time of injection 005 good shot, 650 kA, Sc inj at .55, nl=6.0e19 006 good shot, 650 kA, Sc inj at .55, nl=6e19 007 good shot, 480 kA, Sc inj at .55, nl=5e19, Li pellet at .7 008 good shot, 420 kA, Sc inj at .55, nl=5e19, Li pellet at .7 009 OK shot, nat'l Mo inj at .34, disr'n at .54 010 good shot, 900 kA, Sc inj at .55, nl=6e19, Li pellet at .7 011 good shot, 1 Ma, Sc at .55, nl=7e19 012 early disruption, no useful injection data 013 1 MA, disr'n at .7, Sc inj at .57, nat'l Mo early on--ugly soft x-ray signals 014 good shot, 850 kA, Sc at .57, nl=7e19 015 good shot, 850 kA, Sc at .57, nl=1.7e19 (start of density scan) 016 good shot, 845 kA, Sc at .57, nl=1.3e19 017 good shot, 845 kA, Sc at .57, nl=8.3e19 (achieved through divertor puffing of D2) 018 good shot, 850 kA, Sc at .82 (post flame-out), nl=1.4e20 019 good shot, 830 kA, Sc at .82, nl=1.4e20 (div puffing), inj occurred post flame-out 020 good shot, 850 kA, Sc at .82 (post flame-out), nl=1.4e20 021 early disruption, no useful injection data 022 good shot, 840 kA, attempt a Mo injection at .85, nl=1.8e20, Li pellet at .95 023 good shot, 850 kA, Mo inj at .55, Li pellet at .65, nl=5e19 before pellet 024 early disrup'n (.45 sec)--no useful injection data 025 good shot, 855 kA, Sc inj at .80, nl=9e19 (achieved through divertor puff of He) 026 good shot, 860 kA, Sc at .80, nl=5.5e19 with div puff of He again, Li pellet at .9 027 good shot, 840 kA, Sc at .8, nl=1.3e20 with He through divertor 028 good shot, 813 kA, Sc at .8, nl=1.7e20 with He through divertor This run was highly successful from the point of view of meeting the goals established beforehand. We managed to complete a current scan (and hence a q* scan) over about a factor of about 2.5. Alcator C results say that the impurity particle confinement time should go linearly with (1/q*)--the data we took on this day show that on CMOD, that scaling is not as strong. Alcator C also noticed no real density scaling; our data today may or may not indicate a density scaling, depending on how we treat changing Zeff. The data obtained with changing mass of the background gas are difficult to interpret, but the confinement time does not appear to scale linearly with mass of the background gas as it did on C. Other possible scalings not investigated include kappa (which was fixed at about 1.56 throughout the entire run). Some analysis will also be undertaken to determine penetration efficiencies of the impurities during changing background conditions. |
| Physics Operator Summaries |
| Entered: Jul 7 2004 04:36:50:490PM |
| Author: To Be Determined |
| Summary of run 931019 Impurity transport with current and density scans, and gas Piggyback -- Lithium pellets PO: Marmar SL: Graf Asst: Terry Eng: Bertolino This was a successful run with neither fizzles nor duds. Of the 28 plasma shots, 24 were appropriate for the impurity injection experiment. The plasma current was scanned from .42MA (shot 8) to 1.01MA (11); this was done entirely by changing the I_p waveform in the feedback. In deuterium, the density was scanned from nel=1.6e19 (15) to 1.9e20 (22). There was also helium fueling on shots 24 through 28. Fueling to high density was done through the divertor capillary system, with the A-side valve being used only for the early gas puffing. On the piggy-back experiment, lithium pellets were successfully fired on 12 shots, with 2 of these coming after the plasma had already disrupted. Reliability of the gun was 5/7 for the small pellets and 7/7 for the larger pellets. The time of flight and ablation diagnostics worked well. The large pellets penetrated beyond the magnetic axis and on shot 23 a snake was observed with the tomography. The plasmas survived the pellets well, as long as the target density was not too low and injection occurred well before the end of the shot when the current was already starting to droop. Shot 23 also shows evidence of x-ray peaking and beta_p and the diamagnetic flux also increase after the pellet. This successfully completes the LPI checkout mini-proposal, but the OMA was not working. A summary of LPI shots follows: Shot size time result 6 sm .7 no pellet 7 sm .7 delta nel=3e19 8 sm .7 " " =8.2e19 9 lg .7 plasma disrupted before pellet 10 lg .7 delta nel = 13e19, minor disruptions after pellet 15 lg .7 prompt disruption (target nel = 1.7e19) 16 sm .7 prompt disruption ( " " = 1.2e19) 19 lg .93 delta nel = 11.4e19, prompt disrupt 20 sm .93 no pellet 21 sm .93 disrupt before pellet 22 sm .93 delta nel = 7.9e19 23 lg .65 " " = 10.8e19 (snake) 26 lg .92 " " = 15.2e19 28 lg .92 " " = 11.1e19, prompt disrupt |
| Session Leader Comments | |||
| Oct 19 1993 09:23:55:940AM | Jim Terry | The purpose of this run is the study of trace impurity transport.
We plan to inject (via laser blow-off) the trace impurities Sc, Mo, and Si. We will look at their confinment by looking at them with HIREX, the McPherson, the soft-x-ray arrays, and (for Mo) the Moly Monitor. We will first look at confinement scaling vs q by varying I_p, then we will sit at one (intermediate) current and look at the impurity confinement time at 'low' (nel<5x10^19) and 'high' (nel~1.5x10^20) density. If things go very well, we will attempt to check the mass scaling by puffing He as the working gas. | |
| Oct 19 1993 09:30:31:740AM | 931019001 | Jim Terry | Big Mo injection (natural) at 435 ms.
Very good shot. |
| Oct 19 1993 11:37:08:770AM | 931019001 | Robert Granetz | This shot is a good candidate for a fiducial shot at 0.87 MA. The
pre-fill was 1.3e-5, deuterium. |
| Oct 19 1993 09:56:16:150AM | 931019002 | Jim Terry | Shot disrupted after big Mo injection (natural) at 535 ms.
|
| Oct 19 1993 10:00:37:310AM | 931019003 | Jim Terry | Shot OK, I_p max was .860 MA. nel was about 5x10^19.
|
| Oct 19 1993 10:25:38:870AM | 931019004 | Jim Terry | Good Sc inj at 550 ms, I_p was 0.85 MA, nel was 6.25x10^19.
|
| Oct 19 1993 10:41:57:630AM | 931019005 | Jim Terry | Good Sc inj at 550 ms, I_p was 0.66 MA, nel was 5.8x10^19.
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| Physics Operator Comments | |||
| Oct 19 1993 09:29:26:750AM | 931019001 | Jim Terry | Loaded shot 931014024 in.
We are puffing D_2 from A side. Fill is 1.3e-5 from A side Good shot - I_p=.889 MA, nel~8x10^19 There was a big Mo injection (natural) at 435 ms. shot lasted 1.3 seconds. |
| Oct 19 1993 10:02:52:690AM | 931019001 | Jim Terry | RF limiter was at 92 cm, antenna was at 94 cm
|
| Oct 19 1993 11:36:58:680AM | 931019001 | Robert Granetz | This shot is a good candidate for a fiducial shot at 0.87 MA. The
pre-fill was 1.3e-5, deuterium. |
| Oct 19 1993 11:10:34:260AM | 931019002 | Jim Terry | Lowered the puffed gas slightly,
Shot disrupted at 535ms as a result of a Mo (or Fe) injection. There was also a natural injection at 284 ms. Just before the disruption, I_p was 0.0.827 MA, nel was 3.0x10^19 |
| Oct 19 1993 11:14:36:520AM | 931019003 | Jim Terry | Increased the puffed gas because we believe the last shot disrupted
because the density was too low. Multiple Mo and Fe injections early. I_p max was 0.86 MA, nel at 550 ms was 3.6x10^19. |
| Oct 19 1993 10:24:19:780AM | 931019004 | Jim Terry | RF limiter was moved back from 92 cm to 93 cm, antenna is still at
94 cm. We have increased the puffed gas slightly. Good shot - I_p max = 0.878 MA, nel (at Sc inj) was Good Sc injection at 550 ms. Disrupted at 1.05 sec. |
| Oct 19 1993 10:41:23:230AM | 931019005 | Jim Terry | PF supplies tripped out after the last shot - was reset.
Reduced the demanded I_p flattop value to around 600 kA. Good shot - I_p max = 0.660 MA, nel (at Sc inj) was 5.8x10^19. Good Sc injection at 550 ms. Good current ramp-down, shot lasted 1.3 sec. |
| Oct 19 1993 11:06:54:590AM | 931019006 | Jim Terry | Upped the pulsed gas early (at 77 ms) in order to get rid of the
non-thermal emission seen by the ECE. At Sc injection, I_p was 0.65 MA, nel was 6.0x10^19 Good Sc inj at 550 ms, I_p was 0.66 MA, nel was 5.8x10^19. Good shot, Li pellet attempt at 700 ms, No pellet seen. |
| Oct 19 1993 11:24:46:580AM | 931019007 | Jim Terry | Increased the puffed gas slightly at 77 ms.
Lowered the I_p programming to ask for 0.45 MA flattop. Good shot - I_p at Sc inj was 0.48 MA, nel (at Sc inj) was 4.9x10^19. Good Sc inj at 550 ms. Two small Li pellets at 700 ms!!! |
| Oct 19 1993 11:43:14:140AM | 931019008 | Jim Terry | Reduced the I_p programming to ask for 400 kA.
Good shot - I_p (at Sc inj) was 0.42 MA, nel=4.4x10^19 (at Sc inj). Li pellet at 700ms. |
| Oct 19 1993 11:56:34:780AM | 931019009 | Jim Terry | Increased the feedback gain in the time before 100ms (was 0, now to 5)
Changed the I_p programming to ask for 0.9 MA flattop. Shot disrupted at 560 ms due to (natural) Mo injection at 540. I_p just before disruption 0.89 MA, nel was 6.6x10^19. This is very similar to what happened on shot 002. |
| Oct 19 1993 12:19:10:220PM | 931019010 | Jim Terry | Raised the fill pressure from 1.3e-5 to 1.4e-5.
Changed the Z_cur programming from -3 cm to -2,5 cm. I_p programming kept the same (0.9 MA flattop). Good shot up to Li pellet inj at 700 ms, then just OK. (natural) Mo injection at 330ms I_p (at Sc inj) was 0.90 MA. TCI chans 4 and 5 were not available, but nel (chan 3) was about 7x10^19. Li pellet at 700 ms |
| Oct 19 1993 12:52:48:260PM | 931019011 | Jim Terry | Changed z_cur programming from -2.5 cm to 2.0 cm.
Changed I_p programming to ask for 1 MA. Good Shot until disruption at 870 ms. I_p max was 1.03 MA I_p at Sc inj was 1.0 MA, nel (chan 5 - at inj) was 6.6x10^19 |
| Oct 19 1993 12:48:22:690PM | 931019012 | Jim Terry | Changed I_p to begin ramping down from 1 MA at 700ms.
Poor shot, disrupted at 170 ms, after big injections at 110 ms I_p max was 0.3 MA. |
| Oct 19 1993 12:55:31:330PM | 931019012 | Jim Terry | Changed z_cur programming from -2.0 cm to -1.5 cm.
|
| Oct 19 1993 01:12:06:850PM | 931019013 | Jim Terry | Changed z_cur programming back to that of shot 011 (from -1.5 cm to -2.0 cm.
Disrupted at 800 ms after the current was being ramped down. I_p max was 1.04 MA. I_p at Sc injection (570 ms) was 1.02MA, nel (at the inj) was 4.0x10^19. |
| Oct 19 1993 01:23:51:760PM | 931019014 | Jim Terry | Raised the prefill from 1.3 to 1.4e-5 Torr.
Changed I_p programming to ask for a .85 MA flattop. Reduced the pulsed gas programming in hopes of lowering the density. Disrupted at 1.03 s as the current was being ramped down. I_p max was 0.863 MA. I_p at Sc injection (570 ms) was 0.85 MA, nel (at the inj) was 6.6x10^19. |
| Oct 19 1993 01:41:05:670PM | 931019015 | Jim Terry | Prefill still at 1.4e-5 Torr.
Reduced the pulsed gas programming in hopes of lowering the density. Disrupted at 730 ms after the Li pellet. I_p max was 0.85 MA. I_p at Sc injection (570 ms) was 0.85 MA, nel (at the inj) was 1.6x10^19. |
| Oct 19 1993 01:59:51:420PM | 931019016 | Jim Terry | Prefill still at 1.4e-5 Torr.
Increased the pulsed gas programming slightly, but this didn't seem to increase the density. Disrupted at 730 ms after the Li pellet. I_p max was 0.854 MA. I_p at Sc injection (570 ms) was 0.844 MA, nel (at the inj) was 1.33x10^19. |
| Oct 19 1993 02:21:25:210PM | 931019017 | Jim Terry | Prefill still at 1.4e-5 Torr.
Loaded the pulsed gas programming from shot 931014016 and puffed gas thru capillary #9 (private flux) - plenum pressure was 20.3 psi Disrupted at 1.1 s I_p max was 0.847 MA. I_p at Sc injection (570 ms) was 0.847 MA, nel (at the inj) was 8.01x10^19. 'Flame-out' transition at 716 ms. Max nel was 1.36x10^19. |
| Oct 19 1993 02:33:00:780PM | 931019018 | Jim Terry | Prefill still at 1.4e-5 Torr.
All programming the same as the last shot. Disrupted at 1.05 s I_p max was 0.84 MA. I_p at Sc injection (820 ms) was 0.830 MA, nel (at the inj) was 1.4x10^20. 'Flame-out' transition at 680 ms. Max nel was 1.46x10^19. |
| Oct 19 1993 02:53:35:960PM | 931019019 | Jim Terry | Prefill still at 1.4e-5 Torr.
Increased the pulsed gas early in an attempt to fill in the density trough at 250 ms. Increased the I_p ramp down rate in order to avoid the disruption during the ramp-down. Changed the current ramp-up to smooth out the current rise. Fast Scanning Probe (FSP) in at 500 ms. Disrupted at 950 ms I_p max was 0.84 MA. I_p at Sc injection (820 ms) was 0.830 MA, nel (at the inj) was 1.4x10^20. 'Flame-out' transition at 720 ms. Max nel was 1.47x10^19. There seems to be no natural injection which has triggered the flame out. |
| Oct 19 1993 03:05:18:310PM | 931019020 | Jim Terry | Prefill still at 1.4e-5 Torr.
Fast Scanning Probe (FSP) in at 810 ms. Disrupted at 1.11s I_p max was 0.85 MA. I_p at Sc injection (820 ms) was 0.84 MA, nel (at the inj) was 1.28x10^20. 'Flame-out' transition at 786 ms. Max nel was 1.42x10^19. There seems to be no natural injection which has triggered the flame out. |
| Oct 19 1993 03:29:04:660PM | 931019021 | Jim Terry | Prefill still at 1.4e-5 Torr.
Moved the capillary open time 100 ms earlier (to 100 ms) and increasing the plenum pressure to 25 psi. A-side valve programming unchanged. Lengthened the I_p flattop to just beyond 1 s. Disrupted at 356 ms from too much gas early. |
| Oct 19 1993 03:48:50:790PM | 931019022 | Jim Terry | Prefill still at 1.4e-5 Torr.
Capillary plenum pressure still 25 psi, but moved back to open at 200 ms. A-side valve programming unchanged. Attempted a Mo injection at 850 ms. We saw only a small rise on the Moly Monitor. Li pellet pushed it over the edge at 940 ms. I_p max of 0.834 MA. Very high gas puffed density of 2.0x10^20. First shot with an Argon puff |
| Oct 19 1993 03:51:09:370PM | 931019022 | Jim Terry | 'Flame out' at 570 ms. The earliest transition so far.
|
| Oct 19 1993 04:10:25:170PM | 931019023 | Jim Terry | Prefill still at 1.4e-5 Torr.
Shut off the capillary gas puff and programmed the A-side valve copied from shot 931019002 The Mo injection at 550 ms was very good, seen on Zeff as well. Good Li pellet (with snake) at 650 ms. I_p max of 0.866 MA. I_p (at the Mo inj) was 0.850 MA, nel (at the inj) 5.9x10^19. Argon puff. |
| Oct 19 1993 04:18:31:890PM | 931019024 | Jim Terry | Prefill still at 1.4e-5 Torr.
Capillary #9 WITH He !!!! gas (opening at 200 ms) was used with a plenum pressure of 15 psi. A-side valve programming copied from shot 931019022. Disruption at 397 ms. (Pushed over the edge from either too much gas and/or a Mo injection. I_p max of 0.767 MA. Argon puff. |
| Oct 19 1993 04:36:53:120PM | 931019025 | Jim Terry | Prefill still at 1.4e-5 Torr.
Capillary #9 WITH He gas (opening at 200 ms) was used with a plenum pressure of 9 psi. A-side valve programming still the same. Good shot - I_p max of 0.86 MA. Good Sc inj at 800 ms (I_p = 0.86 MA, nel=9.0x10^19) No 'flame out' seen at these densities in He. Argon puff. |
| Oct 19 1993 04:47:50:680PM | 931019026 | Jim Terry | Prefill still at 1.4e-5 Torr.
Capillary #9 WITH He gas (opening at 200 ms) was used with a plenum pressure reduced of 5.6 psi. A-side valve programming still the same. Good shot - I_p max of 0.86 MA. Good Sc inj at 800 ms (I_p = 0.86 MA, nel=5.7x10^19). Not much of this density is He however. No 'flame out'. |
| Oct 19 1993 05:09:41:930PM | 931019027 | Jim Terry | Prefill still at 1.4e-5 Torr.
Capillary #9 WITH He gas (opening at 200 ms) was used with a plenum pressure reduced of 12.0 psi. A-side valve programming still the same. Good shot - I_p max of 0.84 MA, lasting 1.068 s Good Sc inj at 800 ms (I_p = 0.84 MA, nel=1.31x10^20). 'Flame out' very late. |
| Oct 19 1993 05:23:44:750PM | 931019028 | Jim Terry | Prefill still at 1.4e-5 Torr.
Capillary #9 WITH He gas (opening at 200 ms) was used with a plenum pressure increased to 14.4 psi. A-side valve programming still the same. Good shot - I_p max of 0.832 MA, lasting 0.932 s (pushed over the edge by the Li pellet. Good Sc inj at 800 ms (I_p = 0.822 MA, nel=1.59x10^20). 'Flame out' transition at 712 ms, another transition at 800 ms triggered by the Sc injection. |
| Engineering Operator Comments | ||||
| Shot | Time | Type | Status | Comment |
| 1 | 08:57:41:020AM | Plasma | Ok | no faults |
| 2 | 09:33:51:440AM | Plasma | Ok | no faults |
| 3 | 09:52:10:660AM | Plasma | Ok | no faults |
| 4 | 10:12:35:730AM | Plasma | Ok | EF1L comm fault due to disruption |
| 5 | 10:32:53:330AM | Plasma | Ok | no faults |
| 6 | 10:52:44:590AM | Plasma | Ok | no faults |
| 7 | 11:13:51:030AM | Plasma | Ok | no faults |
| 8 | 11:31:21:920AM | Plasma | Ok | no faults |
| 9 | 11:48:48:080AM | Plasma | Ok | no faults |
| 10 | 12:06:36:120PM | Plasma | Ok | no faults |
| 11 | 12:24:09:650PM | Plasma | Ok | no faults |
| 12 | 12:41:48:610PM | Plasma | Ok | no faults |
| 13 | 12:58:35:520PM | Plasma | Ok | no faults |
| 14 | 01:15:05:570PM | Plasma | Ok | no faults |
| 15 | 01:32:31:450PM | Plasma | Ok | no faults |
| 16 | 01:48:04:560PM | Plasma | Ok | no faults |
| 17 | 02:04:50:020PM | Plasma | Ok | no faults |
| 18 | 02:21:45:480PM | Plasma | Ok | no faults |
| 19 | 02:38:49:790PM | Plasma | Ok | disruption with ef1L comm fault |
| 20 | 02:55:57:690PM | Plasma | Ok | no faults |
| 21 | 03:13:14:330PM | Plasma | Ok | no faults |
| 22 | 03:28:44:510PM | Plasma | Ok | no faults |
| 23 | 03:47:17:010PM | Plasma | Ok | no faults |
| 24 | 04:05:37:630PM | Plasma | Ok | no faults |
| 25 | 04:19:55:940PM | Plasma | Ok | no faults |
| 26 | 04:37:16:050PM | Plasma | Ok | no faults |
| 27 | 04:54:27:450PM | Plasma | Ok | no faults |
| 28 | 05:11:06:770PM | Plasma | Ok | no faults |