| Miniproposals | ||||||||||
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| Operators | |
| Session leader(s): | Amanda Hubbard,Amanda Hubbard |
| Physics operator(s): | Dmitri Mossessian |
| Engineering operator(s): | Gary Dekow,Bill Cochran |
| Engineering Operator Run Comment |
| MP #232 Parameters. Hubbard/Mossessian/Cochran/Dekow. |
| Session Leader Plans |
| Physics Operators Plans |
| Session Leader Summaries |
| Entered: Jul 7 2004 03:49:24:570PM |
| Author: To Be Determined |
Session Leader: Amanda Hubbard Phys. Op: Dmitri Mossessian Eng. Ops: Bill Cochrane RF Ops: Rejean Boivin This run is in support of MP 232, by Greenwald et al, on "Mapping the EDA boundary", and should also be useful for MP 271 "Scaling of Pedestal Parameters". The main aim is to revisit the effect of triangularity, which in the past has been found to be critical for obtaining EDA H-modes, taking advantage of our new pedestal and fluctuation diagnostics. The main questions we hope to answer are: 1) Is the delta boundary reproduced? (delta > 0.35 for EDA) Is there an upper limit? 2) Which pedestal widths (ne, Te, impurities) scale with delta? Do they vary continuously or is there a 'jump' at the EDA-ELM-free boundary? 3) Do edge fluctuations in EDA appear suddenly or gradually near the boundary? 4) Can the EDA boundary be affected by raising density, or power? (There were indications of this on 1000616) Run Plan: 1) Start with 'standard' 1 MA, 5.3 T plasma, q95=4, delta_av=0.4. Decrease triangularity shot to shot, to ~0.2 or until clearly below EDA regime. 2) Scan upwards in delta to ~0.6, or max feasible. In the distant past, there were indications of an upper limit to the EDA regime. 3) Pick a clearly ELM-free case, and raise RF power to 3 MW, or max available. If time, repeat for an EDA case. 4) If things going really well and time remains, raise target ne to nel_01~ 1.3e20 and repeat part of delta scan, near boundary. The results: We only really covered point 1), given the small number of 'good' plasmas. Became mainly ELM-free at triangurity only slightly lower than our 'standard' shape, at delta_av = 0.36. Shots 12 and 17 are the best examples. Pedestal widths did generally get narrower, though they have yet to be examined in detail. Attempts to go lower in delta led to impurity injections and disruptions, perhaps due to the strike pt on the nose (shots 19, 20). The brief H-modes did appear ELM-free. We compromised on delta_u=0.2, delta_l=0.46 (shots 21,23) These still had injections and an early disruption, though. Conclusion: shape scans are not as easy as one might think. This should be revisited at a time when general plasma startup and robustness are better. Given the initially high LH threshold powers (up to 2.6 MW) at each new shape, I suspect wall conditioning may require multiple shots per triangularity. Shot by shot comments (of decent shots): Shot 002: Plasma was OK. H-mode seemed to start ELM-free, was EDA at high RF power, then a long period with no RF, following the trip ~0.8 secs. Looked ELM-free, but according to fluctuations was really steady ohmic EDA. nel got to 2.e20 m-2. Edge ECE was cut off during sweep to 5.1 T. For next shot, use a positive Bt ramp. Shot 004: Good H-mode, steady until ~1.04 secs when RF trips. Got good profiles on ECE and TS. nel_01 1.2-2.05 e20, delta_u=0.32, delta_l=0.52, q95=4-4.1 Use this one; try to drop delta next shot. Shot 006: Lower triangularity; delta_u=0.27, delta_l=0.45, delta_av=0.36 Good RF power, 1.9 MW as requested, but L_MODE! (why?) Good central htg, little edge htg. Shot 010: Lower triangularity; delta_u=0.27, delta_l=0.45, delta_av=0.36 H-mode transition at 3 MW. Looks ELM-free, though there may be ELMs on fast D-alpha. RF trips in H-mode; re-tune and repeat. Shot 012: 2 H-modes, First has 3.2 MW from D+E, but trips from ~0.95 secs. Later H-mode with 1.5 MW from D+J. This looks quite ELM-free, according to lack of fluctuations on reflectometry. q95 is 3.7; drop Ip slightly on next shot. Pedestal widths do seem somewhat narrower than shot 4. Shot 17: Full length plasma. 3 H-modes; look mainly ELM-free though some periods may be marginally EDA. Some RF trips, therefore several different power levels. Didn't get ECE sweep in H-mode. However, try reducing delta some more for the next shot. Shot 19: Got a brief ELM-free H-mode. (took 2.6 MW of RF) But, had some RF trips, followed by a big disruption. delta_L=0.41, delta_u=0.23. Strike pt on nose. Shot 21: delta_L=0.46, delta_u=0.2 Possibly a brief H-mode, but transition and type are not clear. Big injection at 0.8 s trips RF. |
| Physics Operator Summaries |
| Entered: Jul 7 2004 04:37:11:537PM |
| Author: To Be Determined |
| Physop summary for 1000628: MP232 EDA Parameters (triangularity scan) SL Hubbard PO Mossessian _____________________________________________________ Engineering Setup for 1000628 Overnight ECDC in D2, stopping 2 hours before run. Power system setup: Same as for 1000627001 Gas setup: B-Top 6 psi D2 Hybrid Enabled B-side lower 1 psi Argon Hybrid DISABLED B-side upper leave as is Hybrid DISABLED C-side 30 psi D2 Hybrid Enabled J-bottom leave as is Hybrid DISABLED The following Gate Valves should be ENABLED, assuming no vacuum problems: ECE, VUV DNB gate valve should be DISABLED RF setup: RF 2 MW, ramped up from 0.6 to 0.8 sec, then steady. _______________________________________________ Summary: The run was delayed by problems with edge TS CAMAC crate. We started around 9:30. Load shot 100060116 but used segment 1 from 1000627021. It was not a very successful run - out of 23 shots we had 9 fizzles, 1 power supply fault and 6 plasmas disrupted before any useful data could be taken. A series of fizzles was apparently caused by DNB addition of large amount of H2 to the prefill. The DNB was set up to fire around .45 sec and at this setting we had approx. 90% of H2 in the prefill (the D2 prefill pulse had to be dropped to 10 ms). Breakdown was unreliable under these conditions. We disabled the DNB gate valve after shot 15 and that seemed to result in a somewhat more robust startup. Upper and lower triangularity was changed several times during the run (see details). Score: 23 shots 9 fizzles 0 duds 1 OH2 fault 6 disruptions Details: ---------------------------------------------------------------------------- 1000628001 mossessian PHYSICS_OPERATOR Jun 28 2000 9:38:15:420AM Fizzle. According to Steve Wolfe, Bz is too negative. Also, G-side pressure is lower then yesterday's optimum. For next shot: Pulse_gas4 21 ms -> 24 msec, IC_EF4 -1297 -> -1280 ----------------------------------------------------------------------------- 1000628002 mossessian PHYSICS_OPERATOR Jun 28 2000 10:06:18:403AM PLasma. Startup OK. H-mode, but RF trips after reaching 2 MW. For next shot: enable Ar valve and program 40 ms Ar pulse. Change Bt sweep from positive to negative (to higher abs(Bt)) ----------------------------------------------------------------------------- 1000628003 mossessian PHYSICS_OPERATOR Jun 28 2000 10:28:49:810AM Plasma. Disrupts at 1 sec, cause unknown. For next shot: Drop target nl to 1e20. ----------------------------------------------------------------------------- 1000628004 mossessian PHYSICS_OPERATOR Jun 28 2000 10:56:38:216AM Plasma. EDA H-mode. For next shot: Try to decrease upper/lower triang. - increased RXU and RXL by 1 cm ----------------------------------------------------------------------------- 1000628005 mossessian PHYSICS_OPERATOR Jun 28 2000 11:03:52:763AM Fizzle. For next shot: Drop gas pulse 24->21 msec, drop Bz -1280 -> -1290 ----------------------------------------------------------------------------- 1000628006 mossessian PHYSICS_OPERATOR Jun 28 2000 11:30:33:263AM PLasma. Core Te rises to 2keV during RF, but there is no H-mode. Triangularity is lower by about 0.05. For next shot: Enabled DNB valve, drop prefill to 16 ms. ----------------------------------------------------------------------------- 1000628007 mossessian PHYSICS_OPERATOR Jun 28 2000 11:44:51:513AM Fizzle. Too much prefill (.09 mT) For next shot: drop prefill to 12 msec ----------------------------------------------------------------------------- 1000628008 mossessian PHYSICS_OPERATOR Jun 28 2000 12:08:02:216PM Fizzle. Too much prefill again. Bz is a little too high For next shot: drop Bz -1290 -> -1300. DNB lowered the amount of H2 they inject by about 20% ----------------------------------------------------------------------------- 1000628009 mossessian PHYSICS_OPERATOR Jun 28 2000 12:25:58:796PM Plasma. Disrupted @ .55 sec due to a large injection For next shot: Drop prefill to 10 msec ----------------------------------------------------------------------------- 1000628011 mossessian PHYSICS_OPERATOR Jun 28 2000 1:11:16:560PM Fizzle. Bz too low ? For next shot: Bz -1300 -> -1290, Bt from -148000 -> -151000, to compensate for q95 change due to delta change. ----------------------------------------------------------------------------- 1000628012 mossessian PHYSICS_OPERATOR Jun 28 2000 1:33:49:403PM Plasma. For next shot: Drop Ip to -.95e6 to compensate for q95 change. ----------------------------------------------------------------------------- 1000628013 mossessian PHYSICS_OPERATOR Jun 28 2000 1:43:23:840PM Fizzle. Bz too high For next shot: Bz -1290 -> -1300 ----------------------------------------------------------------------------- 1000628014 mossessian PHYSICS_OPERATOR Jun 28 2000 1:56:06:730PM OH2_l power supply fault at -.7 sec ----------------------------------------------------------------------------- 1000628015 mossessian PHYSICS_OPERATOR Jun 28 2000 2:20:08:293PM Fizzle. Probably too much gas + Bz is jumping around from shot to shot. For next shot: Disable DNB gate valve. Return prefill to 20 msec. ----------------------------------------------------------------------------- 1000628016 mossessian PHYSICS_OPERATOR Jun 28 2000 2:59:04:000PM Plasma. Disrupted at .57 sec - injection (?) ----------------------------------------------------------------------------- 1000628017 mossessian PHYSICS_OPERATOR Jun 28 2000 3:02:39:826PM Plasma. For next shot: shift RXL and RXU 1 cm more for lower triangularity ----------------------------------------------------------------------------- 1000628018 mossessian PHYSICS_OPERATOR Jun 28 2000 3:20:59:890PM Fizzle. No apparent reason. For next shot: drop prefill to 18 ms ----------------------------------------------------------------------------- 1000628021 mossessian PHYSICS_OPERATOR Jun 28 2000 4:42:37:593PM PLasma. Upper triang. about 0.21, lower - 0.46 For next shot: no PCS change ----------------------------------------------------------------------------- 1000628022 mossessian PHYSICS_OPERATOR Jun 28 2000 4:43:28:670PM Fizzle. No apparent reason. Bz, Br and G-side gas are same as before. For next shot: Br 0.5mT down just to do something ----------------------------------------------------------------------------- 1000628023 mossessian PHYSICS_OPERATOR Jun 28 2000 4:57:16:326PM Plasma. Disrupted at 0.82 sec. ----------------------------------------------------------------------------- |
| Session Leader Comments | |||
| Jun 28 2000 09:27:54:827AM | Amanda Hubbard | Physics run plan Session Leader: Amanda Hubbard Phys. Op: Dmitri Mossessian Eng. Ops: Bill Cochrane RF Ops: Rejean Boivin This run is in support of MP 232, by Greenwald et al, on "Mapping the EDA boundary", and should also be useful for MP 271 "Scaling of Pedestal Parameters". The main aim is to revisit the effect of triangularity, which in the past has been found to be critical for obtaining EDA H-modes, taking advantage of our new pedestal and fluctuation diagnostics. The main questions we hope to answer are: 1) Is the delta boundary reproduced? (delta > 0.35 for EDA) Is there an upper limit? 2) Which pedestal widths (ne, Te, impurities) scale with delta? Do they vary continuously or is there a 'jump' at the EDA-ELM-free boundary? 3) Do edge fluctuations in EDA appear suddenly or gradually near the boundary? 4) Can the EDA boundary be affected by raising density, or power? (There were indications of this on 1000616) Run Plan: 1) Start with 'standard' 1 MA, 5.3 T plasma, q95=4, delta_av=0.4. Decrease triangularity shot to shot, to ~0.2 or until clearly below EDA regime. 2) Scan upwards in delta to ~0.6, or max feasible. In the distant past, there were indications of an upper limit to the EDA regime. 3) Pick a clearly ELM-free case, and raise RF power to 3 MW, or max available. If time, repeat for an EDA case. 4) If things going really well and time remains, raise target ne to nel_01~ 1.3e20 and repeat part of delta scan, near boundary. | |
| Jun 28 2000 10:22:47:717AM | 1000628002 | Amanda Hubbard | Shot 002: Plasma was OK. H-mode seemed to start ELM-free, was EDA at high RF power, then a long ELM-free period with no RF, following the trip ~0.8 secs. nel got to 2.e20 m-2. Edge ECE was cut off during sweep to 5.1 T. For next shot, use a positive Bt ramp. |
| Jun 28 2000 10:55:20:730AM | 1000628003 | Amanda Hubbard | Shot 003: Disrupts 1.02 seconds; probably an injection. |
| Jun 28 2000 10:58:18:187AM | 1000628004 | Amanda Hubbard | Shot 004: Good H-mode, steady until ~1.04 secs when RF trips. Got good profiles on ECE and TS. nel_01 1.2-2.05 e20, delta_u=0.32, delta_l=0.52, q95=4-4.1 Use this one; try to drop delta next shot. |
| Jun 28 2000 11:33:52:857AM | 1000628006 | Amanda Hubbard | Shot 006: Lower triangularity; delta_u=0.27, delta_l=0.45, delta_av=0.36 Good RF power, 1.9 MW as requested, but L_MODE! (why?) Good central htg, little edge htg. |
| Jun 28 2000 01:46:33:327PM | 1000628010 | Amanda Hubbard | Shot 010: Lower triangularity; delta_u=0.27, delta_l=0.45, delta_av=0.36 H-mode transition at 3 MW. Looks ELM-free, though there may be ELMs on fast D-alpha. RF trips in H-mode; re-tune and repeat. |
| Jun 28 2000 01:50:48:340PM | 1000628012 | Amanda Hubbard | Shot 012: 2 H-modes, First has 3.2 MW from D+E, but trips from ~0.95 secs. Later H-mode with 1.5 MW from D+J. This looks quite ELM-free, according to lack of fluctuations on reflectometry. q95 is 3.7; drop Ip slightly on next shot. Pedestal widths do seem somewhat narrower than shot 4. |
| Jun 28 2000 03:13:17:153PM | 1000628017 | Amanda Hubbard | Shot 17: Full length plasma. 3 H-modes; look mainly ELM-free though some periods may be marginally EDA. Some RF trips, therefore several different power levels. DIdn't get ECE sweep in H-mode. However, try reducing delta some more for the next shot. |
| Jun 28 2000 04:12:44:933PM | 1000628019 | Amanda Hubbard | Shot 19: Got a brief ELM-free H-mode. (took 2.6 MW of RF) But, had some RF trips, followed by a big disruption. delta_L=0.41, delta_u=0.23. Strike pt on nose. |
| Jun 28 2000 04:23:38:030PM | 1000628019 | Amanda Hubbard | Shot 19: Got a brief ELM-free H-mode. (took 2.6 MW of RF) But, had some RF trips, followed by a big disruption. delta_L=0.41, delta_u=0.23. Strike pt on nose. |
| Jun 28 2000 04:27:44:547PM | 1000628021 | Amanda Hubbard | Shot 21: delta_L=0.46, delta_u=0.2 Possibly a brief H-mode, but transition and type are not clear. Big injection at 0.8 s trips RF. Retune, try one more time. |
| Physics Operator Comments | |||
| Jun 28 2000 09:24:56:217AM | Dmitri Mossessian | We were delayed by problems with edge TS crate. Starting at 9:21 Load shot 100060116 Load segment 1 from 1000627021 Coldstart OK _____________________________________________________ Engineering Setup for 1000628 MP232 EDA Parameters (triangularity scan) SL Hubbard PO Mossessian Overnight ECDC in D2, stopping 2 hours before run. Power system setup: Same as for 1000627001 Gas setup: B-Top 6 psi D2 Hybrid Enabled B-side lower 1 psi Argon Hybrid DISABLED B-side upper leave as is Hybrid DISABLED C-side 30 psi D2 Hybrid Enabled J-bottom leave as is Hybrid DISABLED The following Gate Valves should be ENABLED, assuming no vacuum problems: ECE, VUV DNB gate valve should be DISABLED RF setup: RF 2 MW, ramped up from 0.6 to 0.8 secs, then steady. | |
| Jun 28 2000 09:38:15:420AM | 1000628001 | Dmitri Mossessian | Fizzle. According to Steve Wolfe, Bz is too negative. Also, G-side pressure is lower then yesterday's optimum. For next shot: Pulse_gas4 21 ms -> 24 msec IC_EF4 -1297 -> -1280 |
| Jun 28 2000 10:06:18:403AM | 1000628002 | Dmitri Mossessian | PLasma. Startup OK. H-mode, but RF trips after reaching 2 MW. For next shot: eneble Ar valve and program 40 ms Ar pulse. Change Bt sweep from positive to negative (to higher abs(Bt)) |
| Jun 28 2000 10:28:49:810AM | 1000628003 | Dmitri Mossessian | Plasma. Disrupts at 1 sec, cause unknown. For next shot: Drop target nl to 1e20. |
| Jun 28 2000 10:56:38:217AM | 1000628004 | Dmitri Mossessian | Plasma. EDA H-mode. For next shot: Try to decrease upper/lower triang. - increased RXU and RXL by 1 cm |
| Jun 28 2000 11:03:52:763AM | 1000628005 | Dmitri Mossessian | Fizzle. For next shot: Drop gas pulse 24->21 msec, drop Bz -1280 -> -1290 |
| Jun 28 2000 11:30:33:263AM | 1000628006 | Dmitri Mossessian | PLasma. Core Te rises to 2keV during RF, but there is no H-mode. Triangularity is lower by about 0.05. For next shot: Enabled DNB valve, drop prefill to 16 ms. |
| Jun 28 2000 11:44:51:513AM | 1000628007 | Dmitri Mossessian | Fizzle. Too much prefill (.09 mT) For next shot: drop prefill to 12 msec |
| Jun 28 2000 12:08:02:217PM | 1000628008 | Dmitri Mossessian | Fizzle. Too much prefill again. Bz is a little too high For next shot: drop Bz -1290 -> -1300. DNB lowered the amount of H2 they inject by about 20% |
| Jun 28 2000 12:25:58:797PM | 1000628009 | Dmitri Mossessian | Plasma. Disrupted @ .55 sec due to a large injection For next shot: Drop prefill to 10 msec |
| Jun 28 2000 01:11:16:560PM | 1000628011 | Dmitri Mossessian | Fizzle. Bz too low ? For next shot: Bz -1300 -> -1290, Bt from -148000 -> -151000, to compensate for q95 change due to delta change. |
| Jun 28 2000 01:33:49:403PM | 1000628012 | Dmitri Mossessian | Plasma. For next shot: Drop Ip to -.95e6 to compensate for q95 change. |
| Jun 28 2000 01:43:23:840PM | 1000628013 | Dmitri Mossessian | Fizzle. Bz too high For next shot: Bz -1290 -> -1300 |
| Jun 28 2000 01:56:06:730PM | 1000628014 | Dmitri Mossessian | OH2_l power supply fault at -.7 sec |
| Jun 28 2000 02:20:08:293PM | 1000628015 | Dmitri Mossessian | Fizzle. Probably too much gas + Bz is jumping around from shot to shot. For next shot: Disable DNB gate valve. Return prefill to 20 msec. |
| Jun 28 2000 02:59:04:000PM | 1000628016 | Dmitri Mossessian | Plasma. Disrupted at .57 sec - injection (?) |
| Jun 28 2000 03:02:39:827PM | 1000628017 | Dmitri Mossessian | Plasma. For next shot: shift RXL and RXU 1 cm more for lower triangularity |
| Jun 28 2000 03:20:59:890PM | 1000628018 | Dmitri Mossessian | Fizzle. No apparent reason. For next shot: drop prefill to 18 ms |
| Jun 28 2000 03:58:35:983PM | 1000628020 | Dmitri Mossessian | PLasma. Disrupted at .53 sec - injection. The disruption are probably caused by the outer lower stike point being to high in the divertor nose. So we'll try to move RXL back in and push RXU farther out to decrease upper delta. For next shot: RXL 1 cm in, RXU 1 cm out. |
| Jun 28 2000 04:42:37:593PM | 1000628021 | Dmitri Mossessian | PLasma. Upper triang. about 0.21, lower - 0.46 For next shot: no PCS change |
| Jun 28 2000 04:43:28:670PM | 1000628022 | Dmitri Mossessian | Fizzle. No apparent reason. Bz, Br and G-side gas are same as before. For next shot: Br 0.5mT down just to do something |
| Jun 28 2000 04:57:16:327PM | 1000628023 | Dmitri Mossessian | Plasma. Disrupted at 0.82 sec. |
| Engineering Operator Comments | ||||
| Shot | Time | Type | Status | Comment |
| 1 | 09:25:41:733AM | Plasma | Ok | |
| 2 | 09:47:26:797AM | Plasma | Ok | |
| 3 | 10:06:53:530AM | Plasma | Ok | |
| 4 | 10:31:10:530AM | Plasma | Ok | |
| 5 | 10:57:28:107AM | Plasma | Ok | |
| 6 | 11:15:26:483AM | Plasma | Ok | |
| 7 | 11:37:27:670AM | Plasma | Ok | |
| 8 | 11:54:33:403AM | Plasma | Ok | |
| 9 | 12:12:54:263PM | Plasma | Ok | |
| 10 | 12:34:39:310PM | Plasma | Ok | |
| 11 | 12:55:23:890PM | Plasma | Ok | |
| 12 | 01:13:25:607PM | Plasma | Ok | |
| 13 | 01:36:56:467PM | Plasma | Ok | |
| 14 | 01:52:53:920PM | Plasma | Bad | OH2L Crowbar |
| 15 | 02:10:22:950PM | Plasma | Ok | |
| 16 | 02:27:55:153PM | Plasma | Ok | |
| 17 | 02:48:24:967PM | Plasma | Ok | |
| 18 | 03:09:46:873PM | Plasma | Ok | |
| 19 | 03:27:45:140PM | Plasma | Ok | |
| 20 | 03:50:25:547PM | Plasma | Ok | |
| 21 | 04:10:49:780PM | Plasma | Ok | |
| 22 | 04:31:52:093PM | Plasma | Ok | |
| 23 | 04:50:03:653PM | Plasma | Ok | |