| Miniproposals | ||||||||||
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| Operators | |
| Session leader(s): | Brian Labombard |
| Physics operator(s): | Earl Marmar |
| Engineering operator(s): | Sam Pierson,Gary Dekow,Bill Parkin |
| Engineering Operator Run Comment |
| SL XXX PO Marmar EO Pierson MP#406 |
| Session Leader Plans |
| Entered: Feb 17 2005 10:29:24:970AM |
| Author: Brian Labombard |
| MP#406 - Test of new scanning Mach-probe geometry Purpose: The purpose of these experiments is to test a new Mach-probe geometry with the A-port scanning probe. The results of these tests will help with the design of a new wall-scanning probe (WASP) that we are planning to install on the inner wall. Background: The new probe design is based on a 'Gundestrup'-like probe head, except that all ion-collecting surfaces are oblique to the magnetic field lines. (Because of this unique geometry, we call it a 'Bohm-Chodura' probe head, according the sheath boundary conditions that the surfaces impose.) In principle, the probe can provide information on both parallel and cross-field (ExB) flows - something we want to try out. Approach: The approach is to operate the probe in a standard set of well-documented discharges. The best choice for this is an ohmic density scan with plasma current of 0.8 MA and toroidal field of 5.4 tesla. Discharges with LSN and USN topologies will be run. These discharges should give us a known variation in parallel plasma flow response. New information on ExB flow profiles in these discharges would be of high interest. Shot Plan: All shots are 0.8 MA, 5.4 tesla discharges. We will scan ASP, FSP, and ISP probes three times during each shot. If compatible, we will program a wiggle in the inner wall gap, after the third probe scan is complete - otherwise we may want to set aside a shot or two for this. The programmed gap-wiggle will help with testing Boron V Doppler spectroscopy as a means of making parallel flow measurements near the inner wall. Some D2 puffing on the inner midplane will be done (NINJA) to produce B+4 ions locally via CX recombination. Shot#1-3 Reload shot#1050216007 (segment 2 active) - LSN, NL04 = 0.5e20 m^-2 Preprogram NL04 to 0.6 Adjust inner/outer gaps to 1.2 cm. Tweak equilibrium and FSP/ASP/ISP targets. Add inner gap wiggle starting at 1.1s: 1.10 to 1.18s - ramp inner gap 4 mm larger 1.18 to 1.50s - ramp inner gap 16 mm smaller Shot#4-6 Change to segment 3 active - USN, NL04 = 0.45e20 m^-2 Reprogram NL04 = 0.6 Adjust inner/outer gaps to 1.2 cm. Tweak equilibrium and FSP/ASP/ISP targets. Add same inner gap wiggle as above Begin density scan with four shots at each density, 2 in USN and 2 in LSN Shot#7,8 - NL04 = 0.8, USN Switch to LSN 9,10 - NL04 = 0.8, LSN 11,12 - NL04 = 1.0, LSN Switch to USN 13,14 - NL04 = 1.0, USN 15,16 - NL04 = 1.2, USN Switch to LSN 17,18 - NL04 = 1.2, LSN |
| Physics Operators Plans |
| Entered: Feb 16 2005 06:31:53:997PM |
| Author: Earl Marmar |
Overnight ECDC in D2, bake at 60C Engineering setup: Power systems as on 1050216007 Gas setup: ----------- >>> fill B-Top with 6 psi D2 Hybrid Enabled (PG4) >>> fill B-side lower with 1 psi Ar Hybrid DISabled (PG1) >>> fill B-side upper with 30 psi D2 Hybrid DISabled (PG2) >>> fill (former) C-side with 30 psi D2 Hybrid Enabled (PG3) Torvac Setup: -------------- GV1 closed, Bypass to RGA open Torus gate valves closed in Pulse for 5min after shot Gate valves/shutters: ECE open Z-bolo/shutter open Plan: MP#406 - Test of new scanning Mach-probe geometry We will start with LSN, then change back and forth from LSN to USN, scanning density as we go. Inner wall puffs (D2) with NINJA will be used for piggy-back passive CXR measurements on B4+ |
| Session Leader Summaries |
| Entered: Feb 17 2005 10:28:19:780PM |
| Author: Brian Labombard |
| MP#406 - Test of new scanning Mach-probe geometry ______________________________________________________________________________ Purpose: The purpose of these experiments is to test a new Mach-probe geometry with the A-port scanning probe. The results of these tests will help with the design of a new wall-scanning probe (WASP) that we are planning to install on the inner wall. Background: The new probe design is based on a 'Gundestrup'-like probe head, except that all ion-collecting surfaces are oblique to the magnetic field lines. (Because of this unique geometry, we call it a 'Bohm-Chodura' probe head, according the sheath boundary conditions that the surfaces impose.) In principle, the probe can provide information on both parallel and cross-field (ExB) flows - something we want to try out. Approach: The approach is to operate the probe in a standard set of well-documented discharges. The best choice for this is an ohmic density scan with plasma current of 0.8 MA and toroidal field of 5.4 tesla. Discharges with LSN and USN topologies will be run. These discharges should give us a known variation in parallel plasma flow response. New information on ExB flow profiles in these discharges would be of high interest. Plan: All shots are 0.8 MA, 5.4 tesla discharges. We will scan ASP, FSP, and ISP probes three times during each shot. If compatible, we will program a wiggle in the inner wall gap, after the third probe scan is complete - otherwise we may want to set aside a shot or two for this. The programmed gap-wiggle will help with testing Boron V Doppler spectroscopy as a means of making parallel flow measurements near the inner wall. Some D2 puffing on the inner midplane will be done (NINJA) to produce B+4 ions locally via CX recombination. Shot#1-3 Reload shot#1050216007 (segment 2 active) - LSN, NL04 = 0.5e20 m^-2 Preprogram NL04 to 0.6 Adjust inner/outer gaps to 1.2 cm. Tweak equilibrium and FSP/ASP/ISP targets. Add inner gap wiggle starting at 1.1s: 1.10 to 1.18s - ramp inner gap 4 mm larger 1.18 to 1.50s - ramp inner gap 16 mm smaller Shot#4-6 Change to segment 3 active - USN, NL04 = 0.45e20 m^-2 Reprogram NL04 = 0.6 Adjust inner/outer gaps to 1.2 cm. Tweak equilibrium and FSP/ASP/ISP targets. Add same inner gap wiggle as above Begin density scan with four shots at each density, 2 in SNU and 2 in SNL. Shot#7,8 - NL04 = 0.8, USN Switch to SNL 9,10 - NL04 = 0.8, LSN 11,12 - NL04 = 1.0, LSN Switch to SNU 13,14 - NL04 = 1.0, USN 15,16 - NL04 = 1.2, USN Switch to SNL 17,18 - NL04 = 1.2, LSN ______________________________________________________________________________ Result: The run was moderately successful in carrying out the run plan for MP#406. We got good profile data from the three probes in LSN and USN topologies for nominal NL04 values of 0.6, 0.8 and 1.0. We did not get any data at NL04 of 1.2. Kenny was able to take some Boron spectra from the inner wall fibers (with inner-wall NINJA gas puff) using the Chromex spectrometer. Because a Camac crate that triggers the Kaiser spectrometer had to be taken off-line (to get the GKA5* highway back up), Kenny had to switch all fibers over to the Chromex early in the run. An inner gap wiggle was programmed starting after 1.1 seconds for all shots to test the inner-wall fiber signals. NINJA D2 gas-puffing was performed to enhance BV lines and later for GPI. The time of injection was after 1s. The amount was up to 10 torr-liters per shot by the end of the day. The new Mach-probe head on the ASP drive and associated new power supplies to drive it worked very well. The I-V characteristics on all four probes where clean. Current-limiting electronics for arc-suppression worked very well. We saw clear differences in the relative ion saturation current levels among the four probes. These differences changed with density and with LSN/USN topology. The next step is to assemble some analysis software to compute the parallel and perpendicular Mach numbers based on published theoretical models. We also kept an eye on the upper divertor pressures in USN discharges. We saw again today that the ratio of Penning to MKS gauge pressures track with major radius location of the upper strike point. The NINJA gas puff (10 torr-liters) changed the pressure in the upper chamber late in the shot. Still, the Penning/MKS pressure ratio tracked with strike-point location, reinforcing the idea of this causal relationship. This run completes MP#406. ______________________________________________________________________________ Shot log: 1 - LSN, NL04= 0.6, ASP(0), FSP(-10), no ISP, at 0.65, 0.85, 1.05 2 - fizzle 3 - LSN, NL04= 0.68, ASP(+3), FSP(-5), ISP, at 0.65, 0.85, 1.05 4 - fizzle 5 - LSN, NL04= 0.67, ASP(+3), FSP(-5), ISP, at 0.65, 0.85, 1.05 6 - LSN, NL04= 0.62, ASP(+5), FSP(-2), ISP, at 0.65, 0.85, 1.05 - good probe targeting 7 - USN, NL04= 0.62, ASP(+1), FSP(-2), ISP, at 0.65, 0.85, 1.05 - ISP too deep! 8 - fizzle 9 - USN, NL04= 0.56, ASP(+1), FSP(-2), ISP, at 0.65, 0.85, 1.05 - good targeting (except ASP) 10 - USN, NL04= 0.58, ASP(+3), FSP(-2), ISP, at 0.65, 0.85, 1.05 - best targeting 11 - USN, NL04= 0.75, ASP(+3), FSP(-2), ISP, at 0.65, 0.85, 1.05 - ASP could be deeper 12 - USN, NL04= 0.8, ASP(+5), FSP(-2), ISP, at 0.65, 0.85, 1.05 - best targeting 13 - LSN, NL04= 0.88, ASP(+5), FSP(-2), ISP, at 0.65, 0.85, 1.05 - Fsp could be deeper 14 - LSN, NL04= 0.88, ASP(+5), FSP(0), ISP, at 0.65, 0.85, 1.05 - good targeting 15 - LSN, NL04= 1.0, ASP(+5), FSP(3), ISP, at 0.65, 0.85, 1.05 - good targeting, FSP could be deeper 16 - fizzle 17 - LSN, NL04= 1.0, ASP(+5), FSP(3), ISP, at 0.65, 0.85, 1.05 - good targeting 18 - fizzle 19 - USN, NL04= 1.0, ASP(+5), FSP(0), ISP, at 0.65, 0.85, 1.05 - ASP & FSP could be deeper => some UFO's seen early in shot on camera 20 - USN, NL04= 1.0, ASP(+7), FSP(+2), ISP, at 0.65, 0.85, 1.05 - ASP & FSP could be deeper => some UFO's 21 - disrupted at 0.4 s => some UFO's 22 - disrupted at 0.3 s => some UFO's 23 - disrupted at 0.83 s - no probes scanning 24 - fizzle 25 - LSN, full length, NL04= 0.8 - no probes scanning 26 - fizzle 27 - dud |
| Physics Operator Summaries |
| Entered: Feb 24 2005 11:30:09:413AM |
| Author: Earl Marmar |
| A decent run. There were more fizzles than we like, and 2 unexplained duds. Shot 27 was a dud because there
was no EF3 (breaker tripped in INIT and was reset, but it never came on). We were able to switch back and forth between LSN and USN, without obvious problems. Shot 21 (USN) ended very early; it appeared because of a big injection. The next plasma was very short, and dominated by runaways. We went back to SNL, and lowered the target density. The next plasma (23) disrupted at .83 seconds. After a fizzle, we got a good looking shot back. However we ran out of time to get another USN data point for the MP, because of a fizzle and the no-EF3 dud. Programming in the clearin tweak between 1.1 and 1.5 seconds left the plasmas inner-wall limited for the entire rampdown, which may have contributed to many disruptions ~half-way down the ramp. Increasing clearin again after 1.5 seconds seemed to help (shot 25). There were various camac and data problems through the day, but nothing that caused serious delay. Scorecard: Plasmas 19 (3 of which disrupted before 1 s) Fizzles 5 Duds 3 (including 1 from no EF3) Total cycles 27 |
| Session Leader Comments | |||
| Feb 17 2005 12:30:18:097PM | 1050217001 | Brian Labombard | Shot 1 LSN discharge NL04 = 0.6 ASP, FSP scanning at 0.65, 0.85, 1.05 s ISP - not scanning ASP - 5 mm out - ok FSP - 8 mm out - ok Next: repeat with deeper probes and outer gap flatter in time |
| Feb 17 2005 01:00:59:690PM | 1050217003 | Brian Labombard | Shot 3 LSN discharge NL04 = 0.67 ASP, ISP, FSP scanning at 0.65, 0.85, 1.05 s ISP - did not scan, camac problem ASP - Camac problem FSP - some arcing on first scan Next: Try again - same thing |
| Feb 17 2005 02:04:20:737PM | 1050217005 | Brian Labombard | Shot 5 LSN discharge NL04 = 0.65 ASP, ISP, FSP scanning at 0.65, 0.85, 1.05 s ISP - to sep. data look good ASP - could be deeper FSP - could be deeper Next: Repeat with ASP and FSP deeper |
| Feb 17 2005 02:09:13:017PM | 1050217006 | Brian Labombard | Shot 6 LSN discharge NL04 = 0.62 ASP, ISP, FSP scanning at 0.65, 0.85, 1.05 s ISP - to sep. data look good ASP - inside sep - good data FSP - first scan near sep. Next: Go to USN |
| Feb 17 2005 02:26:56:220PM | 1050217007 | Brian Labombard | Shot 7 USN discharge NL04 = 0.62 ASP, ISP, FSP scanning at 0.65, 0.85, 1.05 s ISP - too deep! need to increase gap ASP - near to sep FSP - first scan near sep. Next: Repeat with inner gap -> 12 mm |
| Feb 17 2005 02:52:09:627PM | 1050217009 | Brian Labombard | Shot 9 USN discharge NL04 = 0.57 ASP, ISP, FSP scanning at 0.65, 0.85, 1.05 s ISP - at sep. ASP - could be deeper FSP - first scan near sep. Next: Repeat with ASP deeper |
| Feb 17 2005 03:04:24:097PM | 1050217010 | Brian Labombard | Shot 10 USN discharge NL04 = 0.58 ASP, ISP, FSP scanning at 0.65, 0.85, 1.05 s ISP - at sep. ASP - at sep. FSP - first scan near sep. Next: Go to NL04 = 0.8 |
| Feb 17 2005 03:28:23:940PM | 1050217012 | Brian Labombard | Shot 12 USN discharge NL04 = 0.75 ASP, ISP, FSP scanning at 0.65, 0.85, 1.05 s ISP - at sep. ASP - at sep. FSP - first scan near sep. Next: Go to LSN with NL04 = 0.8 |
| Feb 17 2005 03:44:15:017PM | 1050217013 | Brian Labombard | Shot 13 USN discharge NL04 = 0.87 ASP, ISP, FSP scanning at 0.65, 0.85, 1.05 s ISP - at sep. ASP - at sep. FSP - could be deeper Next: Repeat with NL04 = 0.8 |
| Feb 17 2005 04:08:13:483PM | 1050217014 | Brian Labombard | Shot 14 USN discharge NL04 = 0.87 ASP, ISP, FSP scanning at 0.65, 0.85, 1.05 s ISP - at sep. ASP - at sep. - nice data FSP - first scan to sep. Next: Go to NL04 = 1.0 |
| Feb 17 2005 04:23:29:060PM | 1050217015 | Brian Labombard | Shot 15 USN discharge NL04 = 1.0 ASP, ISP, FSP scanning at 0.65, 0.85, 1.05 s ISP - at sep. ASP - at sep. - nice data FSP - could be deeper Next: Repeat with deeper FSP |
| Feb 17 2005 04:41:35:577PM | 1050217017 | Brian Labombard | Shot 17 USN discharge NL04 = 1.0 ASP, ISP, FSP scanning at 0.65, 0.85, 1.05 s ISP - at sep. ASP - at sep. - nice data FSP - to sep on first scan Next: Go to USN at NL04 = 1.0 |
| Feb 17 2005 05:30:49:530PM | 1050217019 | Brian Labombard | Shot 19 USN discharge NL04 = 1.0 ASP, ISP, FSP scanning at 0.65, 0.85, 1.05 s ISP - at sep. ASP - could be deeper FSP - could be deeper Next: Repeat |
| Feb 17 2005 05:31:28:950PM | 1050217020 | Brian Labombard | Shot 20 USN discharge NL04 = 1.0 ASP, ISP, FSP scanning at 0.65, 0.85, 1.05 s ISP - at sep. ASP - again, could be deeper FSP - again, could be deeper Next: Repeat with deeper FSP, ASP |
| Feb 17 2005 06:17:03:763PM | 1050217023 | Brian Labombard | Shot 23 LSN discharge NL04 = 0.78 disrupted at 0.83 s No probes scanning. |
| Feb 17 2005 06:40:40:950PM | 1050217025 | Brian Labombard | Shot 25 LSN discharge NL04 = 0.8 full length No probes scanning. |
| Physics Operator Comments | |||
| Feb 17 2005 12:35:34:033PM | 1050217001 | Earl Marmar | load from 1050216007 Adjust segment 2 gaps (trying for inner and outer of 1.2 cm) Add gap wiggles after 1.1 seconds, as requested by Session Leader change target density to 6e19 Changes made in segments 2 and 3; for this shot segment 2 is on, segment 3 is off plasma outer gap not quite steady interesting increase in stored energy during the gap wiggle |
| Feb 17 2005 12:43:59:970PM | 1050217002 | Earl Marmar | reduce RCUR from .8 to 1.1 seconds to flatten outer gap fizzle |
| Feb 17 2005 01:33:07:487PM | 1050217003 | Earl Marmar | ef4 20 A more negative before t=0 argon puff to 80 ms (from 50) plasma many camac errors; no H/D |
| Feb 17 2005 01:33:20:347PM | 1050217004 | Earl Marmar | no pcs changes dud |
| Feb 17 2005 01:52:13:207PM | 1050217005 | Earl Marmar | add 3 msec to prepuff plasma H/(H+D) ~ 0.2 |
| Feb 17 2005 02:11:19:080PM | 1050217006 | Earl Marmar | no pcs changes argon plenum pressure increased to 2 psi (from 1 psi) plasma |
| Feb 17 2005 02:22:45:627PM | 1050217007 | Earl Marmar | switch to upper null turn off segment 2 turn on segment 3 plasma gaps are a bit small |
| Feb 17 2005 02:35:56:050PM | 1050217008 | Earl Marmar | increase clearin by 4 mm dud nothing obviously wrong |
| Feb 17 2005 03:00:48:283PM | 1050217009 | Earl Marmar | add 1 msec to prepuff plasma |
| Feb 17 2005 03:01:07:363PM | 1050217010 | Earl Marmar | no pcs changes plasma |
| Feb 17 2005 03:16:57:457PM | 1050217011 | Earl Marmar | nl_04 target to 8e19 (segment 3) plasma density droops a bit disrupt halfway into rampdown |
| Feb 17 2005 03:25:03:673PM | 1050217012 | Earl Marmar | add some maintenance voltage for the pulsed gas between .5 and 1 seconds (segment 3) plasma |
| Feb 17 2005 03:34:20:657PM | 1050217013 | Earl Marmar | back to LSN segment 2 on segment 3 off nl_04 to .8e20 (segment 2) reduce Argon pulse (segment 2) plasma |
| Feb 17 2005 04:04:42:753PM | 1050217014 | Earl Marmar | reduce segment gas pulse maintenance voltage; still asking for 8e19 plasma density still a touch high |
| Feb 17 2005 04:15:25:013PM | 1050217015 | Earl Marmar | nl_04 target to 1e20 (segment 2) reduce prefill puff by 1 msec plasma |
| Feb 17 2005 04:25:35:670PM | 1050217016 | Earl Marmar | tweak the early nl_04, to smooth out the density rise fizzle |
| Feb 17 2005 04:47:50:153PM | 1050217017 | Earl Marmar | reduce prepuff by 2 ms; BR0 offset more negative by 0.5 mTesla plasma density closer to the target value pressure at breakdown is up quite a bit (.05 mT, vs .035 earlier in the run) |
| Feb 17 2005 05:00:22:043PM | 1050217018 | Earl Marmar | back to USN (segment 2 off, segment 3 on) nl_04 prog to 1e20 reduce prefill puff 2 ms fizzle pressure at breakdown .03 mTorr |
| Feb 17 2005 05:08:58:763PM | 1050217019 | Earl Marmar | BR0 offset less negative by 0.5 mTesla plasma |
| Feb 17 2005 05:25:49:013PM | 1050217020 | Earl Marmar | no pcs changes plasma |
| Feb 17 2005 05:40:17:263PM | 1050217021 | Earl Marmar | tweak clearin during rampdown, after 1.5 s, to try to keep it diverted longer (changed in both segment 2 and segment 3; only segment 3 is active) plasma disrupt at .407 s (something fell in?) |
| Feb 17 2005 06:03:38:420PM | 1050217022 | Earl Marmar | no pcs changes plasma nasty, short shot, lots of hards something sticking in? |
| Feb 17 2005 06:15:53:730PM | 1050217023 | Earl Marmar | back to SNL, segment 2 on, segment 3 off increase prefill puff by 2 msec nl_04 target to 8e19 plasma disrupt at .83; similar to 21, but lasted longer |
| Feb 17 2005 06:23:10:153PM | 1050217024 | Earl Marmar | no pcs changes fizzle |
| Feb 17 2005 06:40:14:933PM | 1050217025 | Earl Marmar | BR_0 offset more negative by 0.5 mTesla plasma looks much nicer; ramped all the way down |
| Feb 17 2005 06:51:36:187PM | 1050217026 | Earl Marmar | back to USN segment 2 off, segment 3 on EF4 20 amps more negative in segment 1 fizzle |
| Feb 17 2005 07:02:14:950PM | 1050217027 | Earl Marmar | decrease prepuff 1 ms BR_0 offset .5 mTesla less negative dud no EF3 |
| Engineering Operator Comments | ||||
| Shot | Time | Type | Status | Comment |
| 1 | 12:12:30:910PM | Plasma | Ok | |
| 2 | 12:36:48:707PM | Plasma | Ok | |
| 3 | 12:49:23:190PM | Plasma | Ok | |
| 4 | 01:26:45:660PM | Plasma | Ok | |
| 5 | 01:39:43:393PM | Plasma | Ok | |
| 6 | 02:01:20:347PM | Plasma | Ok | |
| 7 | 02:13:45:080PM | Plasma | Ok | |
| 8 | 02:26:27:520PM | Plasma | Ok | |
| 9 | 02:38:51:563PM | Plasma | Ok | |
| 10 | 02:51:26:363PM | Plasma | Ok | |
| 11 | 03:04:12:520PM | Plasma | Ok | |
| 12 | 03:17:16:190PM | Plasma | Ok | |
| 13 | 03:29:33:270PM | Plasma | Ok | |
| 14 | 03:56:52:680PM | Plasma | Ok | |
| 15 | 04:10:57:780PM | Plasma | Ok | |
| 16 | 04:23:29:967PM | Plasma | Ok | |
| 17 | 04:36:06:967PM | Plasma | Ok | |
| 18 | 04:48:41:733PM | Plasma | Ok | |
| 19 | 05:01:25:873PM | Plasma | Ok | |
| 20 | 05:17:50:467PM | Plasma | Ok | |
| 21 | 05:30:43:357PM | Plasma | Ok | |
| 22 | 05:55:20:967PM | Plasma | Ok | |
| 23 | 06:08:44:153PM | Plasma | Ok | |
| 24 | 06:21:16:530PM | Plasma | Ok | |
| 25 | 06:33:39:263PM | Plasma | Ok | |
| 26 | 06:47:26:170PM | Plasma | Ok | |
| 27 | 07:00:01:280PM | Plasma | Bad | No EF3 |