| Miniproposals | ||||||||||
|
| Operators | |
| Session leader(s): | Brian Labombard |
| Physics operator(s): | Dmitri Mossessian |
| Engineering operator(s): | Bill Parkin,Bill Byford |
| Engineering Operator Run Comment |
| SL:Labombard,PO:Mossessian,EO:Byford,Parkin MP 267 Dependence of SOL Flu |
| Session Leader Plans |
| Physics Operators Plans |
| Session Leader Summaries |
| Entered: Jul 7 2004 03:49:25:163PM |
| Author: To Be Determined |
| MP#267 - reversed field "Dependence of SOL Fluctuations and Particle Transport on Collisionality" - reversed field, Day 1 Session Leader - B. LaBombard Phys Op - D. Mossessian Overall objectives of MP#267: "The purpose of these experiments is to explore the dependence of SOL fluctuation characteristics and attendant cross-field particle transport on the collisionality of the SOL." Reason for today's run: Note: Runs 1001101 and 1001102 were also aimed at completing Day 1 of this MP, but were mostly unsuccessful. So we attempted to do Day 1 of this MP again today. Reversed field/current allows some important measurements to be made on particle transport in the SOL and the associated levels of plasma turbulence. From a series of shots over ~2 run days we hope to do the following: (1) get data on SOL particle transport (using Ly-alpha diag.) in reversed field. Does the field direction affect the 'scaling' of Deff with collisionality? (2) get data on in-out asymmetries. The outer divertor conditions should change in reversed B. This may impact (1) through changes in the sheath conditions at the divertor plate (e.g., affecting the propagation velocity of the 'blobs' if they somehow involve the 'sheath impedance' via a theory such as that outlined recently by S. Krasheninnikov) (3) get data on field-reversed C2D4 plumes. ExB should now carry the plume away from the probe shaft, resulting in plumes that may be easier to interpret. The 'reversed flows' associated with low collisionality near the separatrix should now become 'normal flows' with reversed B. This should be interesting for the plumes. The magnitude of Er in reversed B is of interest also. (4) get fluctuation data from scanning probe and fast diodes systems. Is the SOL plasma fluctuation character the same in reversed B? Today's run was to cover the Day 1 plan outlined in MP#267: Day 1 (today): Fine density scan at fixed plasma current (0.8 MA) and toroidal field (5.3 tesla). Results: This day was only slightly better than 1001102. We got only 10 usable plasmas, but because we had the targeting already set up from yesterday's run, we were able to make good use of 8-1/2 of these. We managed to get another rough density scan: NL04 ~0.5, ~0.7, ~1.0, ~1.2. It is time to declare that Day 1 for the reversed MP267 is complete. We should have enough data to see if fluctuations, particle transport and its scaling with collisionality cares about B field direction. The divertor probes operated much better today indicating that perhaps they were contaminated from the recent 'up-to-air' and needed to be conditioned with plasma. Still, there are some problems with the interpreting the I-V characteristics on the outer divertor when the temperature there gets low there (shots with NL04 > ~ 1.0). These 'artifacts' are not seen in normal field direction plasmas so the field direction must somehow enter into the explanation. There are also some interesting cases when the electron temperatures reported by the East and West probes were different on the ASP, favoring higher Te on the West probe. These need to be look at carefully. The bias voltage range on the East and West probes were different and it is important to sort out if an 'artifact' is introduced by this somehow. In-out divertor asymmetries appeared again today, favoring somewhat hotter Te on the inner divertor, but not always. The East probe (or its coaxial cable) on the ASP continues to give us trouble. The probe again exhibited intermittent short-circuit behavior. Shot notes: FSP setup: N, S in Vf mode, E-W in double probe sweep mode ASP setup: N, S in Vf mode, E,W in single probe sweep mode ASP East probe was operated with reduced bias (except for shot#22) to try to work-around an intermittent short circuit problem. FSP and ASP always scanning at .7, .95 and 1.2 sec Shot 2 - NL04 ~ 0.5 ASP in single scan dwell/fluctuation mode - this was not successful, the East and West probes were swept by mistake (change in power supply arrangement). Divetor probes in fluctuation mode Shot 10 - NL04 ~ 0.5 ASP to separatrix. East probe has intermittent short FSP in far SOL with plumes Shot 11 - NL04 ~ 0.7 ramping to > 0.8 ASP to separatrix. East probe has intermittent short FSP in far SOL with plumes Shot 12 - NL04 ~ 0.75 ramping to ~ 0.9 FSP scanning to LCFS with plumes Shot 13 - NL04 ~1.0 ASP to separatrix. East probe has intermittent short, operating with reduced bias. FSP scanning to LCFS with plumes Shot 14 - NL04 ~1.0 ASP to separatrix. FSP scanning outside LCFS with plumes Shot 15 - NL04 ramping 1.0 to 1.2 ASP not quite to separatrix? FSP scanning outside LCFS with plumes Shot 16 - NL04 ramping 1.15 to 1.3 ASP to separatrix. FSP scanning to LCFS with plumes Shot 21 - NL04 ramping 0.95 to 1.05 ASP to separatrix. FSP scanning to far SOL with plumes Shot 22 - NL04 ramping 0.75 then an injection increases the density to 1.3 ASP beyond separatrix (may cause injection). East probe operating with FULL bias. FSP scanning far SOL with plumes |
| Physics Operator Summaries |
| Entered: Jul 7 2004 04:37:12:600PM |
| Author: To Be Determined |
| Run summary for November 3, 2000 SL LaBombard PO Mossessian Run in support of MP 267 - Dependence of SOL Fluctuations and Particle Transport on Collisionality now with reversed (positive) toroidal field and plasma current _________________________________________________ Run plan: overnight discharge cleaning in D_2, stopping 2 hours before the run. Run begins at 9:00 and ends at 17:00. Cell will close at 7:30AM Power system setup as on 1001012017 Gas setup - fill B-top with 6 psi of D2 Hybrid enabled fill B-side lower with 1 psi of Ar Hybrid enabled fill B-side upper with 35 psi of D2 Hybrid DISABLED (for ECDC) fill C-side with 30 psi of D2 Hybrid enabled leave J-bottom as is Hybrid DISABLED The following gate valves should be enabled, assuming no vacuum problems: ECE, VUV, NPA (aka Beast) This will be an ohmic run; RF is not required though it may do coupling studies. The purpose of these experiments is to explore the dependence of SOL fluctuation characteristics and attendent cross-field particle transport on the collisionality of the SOL. ________________________________________________ Summary: There was a lot of problems with startup - fields changing, plasma hitting outer wall, having vertical problems and so on (see details below). But there were good shots too. Basically, when Br, Bz and prefill were set correctly, plasma run well and the required density scan was accomplished. Scorecard: 9 plasmas 13 fizzles 1 dud 23 shots _______________________________________________ Details: 1001103001 Fizzle. Br and Bz too high. For next shot: Drop Br offset by 1 mT, Bz 1325 -> 1315 1001103002 Plasma. Br may be a little too low now, there is some vertical motion after breakdown. For next shot: no changes 1001103003 Fizzle. It seems the plasma moves up too much. Also the gas is a little higher than on shot 2 For next shot: Lower Br a little, lower gas 21 -> 19 msec 1001103004 Fizzle. Bz too negative ? For next shot: get Bz back to initial setting 1001103005 Fizzle. For next shot: Load shot 2, lower gas to 20 msec, add .5mT Br offset 1001103006 Fizzle. Fields look fine. Current rises slow. For next shot: Lower gas to 19 msec 1001103007 Fizzle. Lost some magnetics data (Magnetics TRAQ_1 data corrupted), so we don't know how it moves, but it looks like it hit something (too much CII). For next shot: Following Steve Wolfe's suggestion, drop EF1 both lower and upper by 100A to make it more vertically stable. No other changes. 1001103008 Dud. Bz is too negative (as it should be because of EF1 change) For next shot: EF4 1315 -> 1335 1001103009 Fizzle. Bz still looks too low. For next shot: EF4 1335 -> 1350 1001103010 Plasma. Nice breakdown but hesitation after 0.01. For next shot: Drop EF4 1350 ->1345 to get slightly more negative Bz. target nl -> 7e19, right gap to 1.5 cm (was about 1 cm) - RCUR down by 0.25 cm 1001103011 Plasma. Bad hesitation. For next shot: Increase gas a little trying to slow current rise. Also tweak RCUR a little around .7 sec to make right gap more steady 1001103012 Plasma. Same as shot 11. For next shot: Lower Bz EF4 1345 -> 1340 Target nl to 1e20 1001103013 Plasma. For next shot: no changes 1001103014 Plasma. For next shot: target to 1.2e20 1001103015 Plasma. For next shot: no changes 1001103016 Plasma. Killed by a vertical instability that develops after 1 sec For next shot: Set EFC limit to 900 V (was 800) to help stabilize things. target back to 1.oe20 1001103017 Fizzle. Bz seems to be a little low For next shot: Bz up, EF4 1340 -> 1345 1001103018 Fizzle. Bz still too low - plasma's on the wall For next shot: EF4 1345 -> 1360 (Bz up) 1001103019 Fizzle. Plasma starts up real nice, and then something hits it at 0.015 sec. For next shot: Add 1 mT to Br offset to push plasma down 1001103020 Fizzle. May be it's too far out. For next shot: Drop EF4 1360 -> 1350, and return Br back to level of shot 19 1001103021 Plasma. Early breakdown, but then it hits outer wall again. For next shot: Drop Bz EF4 1350 -> 1345, gas to 21 msec, target nl to 7e19 1001103022 Plasma. Massive injection at .95 sec and disruption at 1.25 For next shot: Set target nl to 5e19 1001103023 Fizzle. |
| Session Leader Comments | |||
| Nov 3 2000 08:45:15:297AM | Brian Labombard | MP#267 - reversed field "Dependence of SOL Fluctuations and Particle Transport on Collisionality" - reversed field, Day 1 Note: Runs 1001101 and 1001102 were also aimed at completing Day 1 of this MP, but were unsuccessful. So we are attempting to do Day 1 of this MP again today. Session Leader - B. LaBombard Phys Op - D. Mossessian ============================================================================== Overall objectives of MP#267: "The purpose of these experiments is to explore the dependence of SOL fluctuation characteristics and attendant cross-field particle transport on the collisionality of the SOL." Reason for today's run: Reversed field/current allows some important measurements to be made on particle transport in the SOL and the associated levels of plasma turbulence. From a series of shots over ~2 run days we hope to do the following: (1) get data on SOL particle transport (using Ly-alpha diag.) in reversed field. Does the field direction affect the 'scaling' of Deff with collisionality? (2) get data on in-out asymmetries. The outer divertor conditions should change in reversed B. This may impact (1) through changes in the sheath conditions at the divertor plate (e.g., affecting the propagation velocity of the 'blobs' if they somehow involve the 'sheath impedance' via a theory such as that outlined recently by S. Krasheninnikov) (3) get data on field-reversed C2D4 plumes. ExB should now carry the plume away from the probe shaft, resulting in plumes that may be easier to interpret. The 'reversed flows' associated with low collisionality near the separatrix should now become 'normal flows' with reversed B. This should be interesting for the plumes. The magnitude of Er in reversed B is of interest also. (4) get fluctuation data from scanning probe and fast diodes systems. Is the SOL plasma fluctuation character the same in reversed B? Today's run was to cover the Day 1 plan outlined in MP#267: Day 1 (today): Fine density scan at fixed plasma current (0.8 MA) and toroidal field (5.3 tesla). | |
| Nov 3 2000 09:40:57:467AM | 1001103002 | Brian Labombard | Shot 2 - NL04 ~ 0.5 ASP in single scan dwell/fluctuation mode Divetor probes in fluctuation mode FSP scanning at 0.7, 0.95, and 1.2 sec Next shot - repeat with ASP scanning to LCFS and FSP in far SOL |
| Nov 3 2000 09:57:05:857AM | 1001103003 | Brian Labombard | Shot 3 - Fiz Next shot - try again, with FSP scaning in far SOL and ASP/DIV in single scan fluctuation mode |
| Nov 3 2000 10:22:45:000AM | 1001103005 | Brian Labombard | Shot 4,5 - Fiz Next shot - try again, with FSP scaning in far SOL and ASP scanning to sep. |
| Nov 3 2000 12:12:02:047PM | 1001103010 | Brian Labombard | Shot 10 - NL04 ~ 0.5 Setup: ASP N,S in Vf mode, E,W in single probes sweep mode ASP & FSP scanning at .7, .95, and 1.2 sec ASP to separatrix. East probe has intermitent short FSP in far SOL with plumes Next shot - go to NL04 ~ 0.7 |
| Nov 3 2000 12:38:31:123PM | 1001103011 | Brian Labombard | Shot 11 - NL04 ~ 0.7 ramping to > 0.8 Setup: ASP N,S in Vf mode, E,W in single probes sweep mode ASP & FSP scanning at .7, .95, and 1.2 sec ASP to separatrix. East probe has intermitent short FSP in far SOL with plumes Next shot - repeat with FSP at separatrix |
| Nov 3 2000 12:57:47:983PM | 1001103012 | Brian Labombard | Shot 12 - NL04 ~ 0.75 ramping to ~ 0.9 Setup: ASP N,S in Vf mode, E,W in single probes sweep mode ASP & FSP scanning at .7, .95, and 1.2 sec ASP to separatrix. East probe has intermitent short, operating with reduced bias. FSP scanning to LCFS with plumes Next shot - go to NL04 ~ 1.0 |
| Nov 3 2000 01:29:48:403PM | 1001103013 | Brian Labombard | Shot 13 - NL04 ~1.0 Setup: ASP N,S in Vf mode, E,W in single probes sweep mode ASP & FSP scanning at .7, .95, and 1.2 sec ASP to separatrix. East probe has intermitent short, operating with reduced bias. FSP scanning to LCFS with plumes Next shot - repeat with ASP further in and FSP pulled out |
| Nov 3 2000 01:48:25:327PM | 1001103014 | Brian Labombard | Shot 14 - NL04 ~1.0 Setup: ASP N,S in Vf mode, E,W in single probes sweep mode ASP & FSP scanning at .7, .95, and 1.2 sec ASP to separatrix. East probe has intermitent short, operating with reduced bias. FSP scanning outside LCFS with plumes Next shot - go to NL04 ~ 1.2 |
| Nov 3 2000 02:08:21:153PM | 1001103015 | Brian Labombard | Shot 15 - NL04 ramping 1.0 to 1.2 Setup: ASP N,S in Vf mode, E,W in single probes sweep mode ASP & FSP scanning at .7, .95, and 1.2 sec ASP to separatrix. East probe has intermitent short, operating with reduced bias. FSP scanning outside LCFS with plumes Next shot - repeat with ASP and FSP inserted deeper. |
| Nov 3 2000 02:33:37:950PM | 1001103016 | Brian Labombard | Shot 16 - NL04 ramping 1.15 to 1.3 Setup: ASP N,S in Vf mode, E,W in single probes sweep mode ASP & FSP scanning at .7, .95, and 1.2 sec ASP to separatrix. East probe has intermitent short, operating with reduced bias. FSP scanning to LCFS with plumes Next shot - got back to NL04 ~ 1.0 with FSP targeted 7 mm out. |
| Nov 3 2000 04:25:10:623PM | 1001103021 | Brian Labombard | Shot 21 - NL04 ramping 0.95 to 1.05 Setup: ASP N,S in Vf mode, E,W in single probes sweep mode ASP & FSP scanning at .7, .95, and 1.2 sec ASP to separatrix. East probe operating with reduced bias. FSP scanning to far SOL with plumes Next shot - go to NL04 ~ 0.7, again with FSP targeted 7 mm out. |
| Nov 3 2000 04:53:24:827PM | 1001103022 | Brian Labombard | Shot 22 - NL04 ramping 0.75 then an injection increases the density to 1.3 Setup: ASP N,S in Vf mode, E,W in single probes sweep mode ASP & FSP scanning at .7, .95, and 1.2 sec ASP to separatrix. East probe operating with FULL bias. FSP scanning to far SOL with plumes Next shot - got to NL04 ~ 0.5, again with FSP targeted 7 mm out. |
| Physics Operator Comments | |||
| Nov 3 2000 08:45:27:310AM | Dmitri Mossessian | Run plan: SL LaBombard PO Mossessian MP 267 Dependence of SOL Fluctuations and Particle Transport on Collisionality now with reversed (positive) toroidal field and plasma current overnight discharge cleaning in D_2, stopping 2 hours before the run. Run begins at 9:00 and ends at 17:00. Cell will close at 7:30AM Power system setup as on 1001012017 Gas setup - fill B-top with 6 psi of D2 Hybrid enabled fill B-side lower with 1 psi of Ar Hybrid enabled fill B-side upper with 35 psi of D2 Hybrid DISABLED (for ECDC) fill C-side with 30 psi of D2 Hybrid enabled leave J-bottom as is Hybrid DISABLED The following gate valves should be enabled, assuming no vacuum problems: ECE, VUV, NPA (aka Beast) This will be an ohmic run; RF is not required though it may do coupling studies. The purpose of these experiments is to explore the dependence of SOL fluctuation characteristics and attendent cross-field particle transport on the collisionality of the SOL. ________________________________________________ 8:40 AM. Start PCS Load shot 1001102020 Coldstart OK | |
| Nov 3 2000 09:19:44:547AM | 1001103001 | Dmitri Mossessian | Fizzle. Br and Bz too high. For next shot: Drop Br offset by 1 mT, Bz 1325 -> 1315 |
| Nov 3 2000 09:36:46:437AM | 1001103002 | Dmitri Mossessian | Plasma. Br may be a little too low now, there is some vertical motion after breakdown. For next shot: no changes |
| Nov 3 2000 09:57:58:577AM | 1001103003 | Dmitri Mossessian | Fizzle. It seems the plasma moves up too much. Also the gas is a little higher than on shot 2 For next shot: Lower Br a little, lower gas 21 -> 19 msec |
| Nov 3 2000 10:10:35:343AM | 1001103004 | Dmitri Mossessian | Fizzle. Bz too negative ? For next shot: get Bz back to initial setting |
| Nov 3 2000 10:29:04:513AM | 1001103005 | Dmitri Mossessian | Fizzle. For next shot: Load shot 2, lower gas to 20 msec, add .5mT Br offset |
| Nov 3 2000 10:50:15:230AM | 1001103006 | Dmitri Mossessian | Fizzle. Fields look fine. Current rises slow. For next shot: Lower gas to 19 msec |
| Nov 3 2000 11:21:11:980AM | 1001103007 | Dmitri Mossessian | Fizzle. Lost some magnetics data (Magnetics TRAQ_1 data corrupted), so we don't know how it moves, but it looks like it hit something (too much CII). For next shot: Following Steve Wolfe's suggestion, drop EF1 both lower and upper by 100A to make it more vertically stable. No other changes. |
| Nov 3 2000 11:58:19:763AM | 1001103008 | Dmitri Mossessian | Dud. Bz is too negative (as it should be because of EF1 change) For next shot: EF4 1315 -> 1335 |
| Nov 3 2000 11:53:30:327AM | 1001103009 | Dmitri Mossessian | Fizzle. Bz still looks too low. For next shot: EF4 1335 -> 1350 |
| Nov 3 2000 12:16:13:683PM | 1001103010 | Dmitri Mossessian | Plasma. Nice breakdown but hesitation after 0.01. For next shot: Drop EF4 1350 ->1345 to get slightly more negative Bz. target nl -> 7e19, right gap to 1.5 cm (was about 1 cm) - RCUR down by 0.25 cm |
| Nov 3 2000 12:36:24:903PM | 1001103011 | Dmitri Mossessian | Plasma. Bad hesitation. For next shot: Increase gas a little trying to slow current rise. Also tweak RCUR a little around .7 sec to make right gap more steady |
| Nov 3 2000 12:54:50:793PM | 1001103012 | Dmitri Mossessian | Plasma. Same as shot 11. For next shot: Lower Bz EF4 1345 -> 1340 Target nl to 1e20 |
| Nov 3 2000 01:22:43:687PM | 1001103013 | Dmitri Mossessian | Plasma. For next shot: no changes |
| Nov 3 2000 01:44:17:153PM | 1001103014 | Dmitri Mossessian | Plasma. For next shot: target to 1.2e20 |
| Nov 3 2000 02:10:35:763PM | 1001103015 | Dmitri Mossessian | Plasma. For next shot: no changes |
| Nov 3 2000 02:35:15:967PM | 1001103016 | Dmitri Mossessian | Plasma. Plasma is being killed by a vertical instability that develops after 1 sec For next shot: Set EFC limit to 900 V (was 800) to help stabilize things. target back to 1.oe20 |
| Nov 3 2000 03:01:38:483PM | 1001103017 | Dmitri Mossessian | Fizzle. Bz seems to be a little low For next shot: Bz up, EF4 1340 -> 1345 |
| Nov 3 2000 03:18:42:780PM | 1001103018 | Dmitri Mossessian | Fizzle. Bz still too low - plasma's on the wall For next shot: EF4 1345 -> 1360 (Bz up) |
| Nov 3 2000 03:45:57:297PM | 1001103019 | Dmitri Mossessian | Fizzle. Plasma starts up real nice, and then something hits it at 0.015 sec. For next shot: Add 1 mT to Br offset to push plasma down |
| Nov 3 2000 03:56:34:403PM | 1001103020 | Dmitri Mossessian | Fizzle. May be it's too far out. For next shot: Drop EF4 1360 -> 1350, and return Br back to level of shot 19 |
| Nov 3 2000 04:19:24:967PM | 1001103021 | Dmitri Mossessian | Plasma. Early breakdown, but then it hits outer wall again. For next shot: Drop Bz EF4 1350 -> 1345, gas to 21 msec, target nl to 7e19 |
| Nov 3 2000 04:45:59:327PM | 1001103022 | Dmitri Mossessian | Plasma. Massive injection at .95 sec and disruption at 1.25 For next shot: Set target nl to 5e19 |
| Nov 3 2000 05:07:46:577PM | 1001103023 | Dmitri Mossessian | Fizzle. Br too low ? |
| Engineering Operator Comments | ||||
| Shot | Time | Type | Status | Comment |
| 1 | 09:06:59:530AM | Plasma | Ok | |
| 2 | 09:26:58:890AM | Plasma | Ok | |
| 3 | 09:43:00:327AM | Plasma | Ok | |
| 4 | 10:01:54:327AM | Plasma | Ok | |
| 5 | 10:18:58:670AM | Plasma | Ok | |
| 6 | 10:38:32:077AM | Plasma | Ok | |
| 7 | 11:03:02:123AM | Plasma | Ok | |
| 8 | 11:23:05:640AM | Plasma | Ok | |
| 9 | 11:40:13:123AM | Plasma | Ok | |
| 10 | 11:58:33:107AM | Plasma | Ok | |
| 11 | 12:24:24:780PM | Plasma | Ok | |
| 12 | 12:45:54:810PM | Plasma | Ok | |
| 13 | 01:14:57:590PM | Plasma | Ok | |
| 14 | 01:36:12:780PM | Plasma | Ok | |
| 15 | 01:58:04:293PM | Plasma | Ok | |
| 16 | 02:23:16:857PM | Plasma | Ok | |
| 17 | 02:48:31:903PM | Plasma | Ok | |
| 18 | 03:08:16:827PM | Plasma | Ok | |
| 19 | 03:30:43:047PM | Plasma | Ok | |
| 20 | 03:51:27:593PM | Plasma | Ok | |
| 21 | 04:12:39:733PM | Plasma | Ok | |
| 22 | 04:37:26:030PM | Plasma | Ok | |
| 23 | 05:04:01:153PM | Plasma | Ok | |