| Miniproposals | ||||||||||
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| Operators | |
| Session leader(s): | Martin Greenwald |
| Physics operator(s): | Earl Marmar |
| Engineering operator(s): | Bill Cochran |
| Engineering Operator Run Comment |
| MP 232 EDA parameter scans.Greenwald/Marmar/Cochran. |
| Session Leader Plans |
| Physics Operators Plans |
| Session Leader Summaries |
| Entered: Jul 7 2004 03:49:23:600PM |
| Author: To Be Determined |
| Run Summary for 1000524 mp 232 Mapping EDA/ELMfree boundary - kappa scans Session Leader - Greenwald Phys Op - Marmar ============================ Plan: The purpose of these experiments is to continue the investigations into the scaling of the EDA/ELMfree boundary with the ultimate goal of understanding the physics of EDA. We will also take the opportunity to look for type I ELMs. So far, we have determined that EDA is most likely at lower plasma current ($q_{95} \ge 3.7$), for moderate plasma shaping ($\delta \sim 0.35 - 0.55$) and at high neutral pressures. The degradation in particle confinement that accompanies EDA is correlated with changes in impurity density profiles which are steeper in ELMfree and scale with the parameters listed above. Increased edge fluctuations also accompany EDA. [4] It is worth noting, that theories for ELMs involve the MHD stability of the transport barrier region. Plasma shape - particularly triangularity - is predicted to have a strong effect on that stability. The edge safety factor is also predicted to influence stability[5]. The dependencies that we have observed are superficially consistent with these predictions, but only if we identify EDA as the more stable state. This seems to be contradicted by the edge fluctuations and lower particle confinement that is observed in that regime. We will begin with a kappa scan. Starting at 1.65 and Ip = 1 MA we will scan down to kappa=1.55 and Ip = 0.94 (q ~const). The current will be adjusted up or down in search of the EDA/ELMfree boundary. When this is complete we will reverse the process scanning to higher kappa (~1.75). An excursion in Bt was used to help GPC get edge profiles ============================== Results: At first glance, there was no obvious effects of elongation on the EDA/ELMfree boundary. The EDA or ELMfree character did not change markedly throughout the scans. There were differences due to impurity injections, RF power changes, radiated power build-up etc, but nothing obviously systematic with kappa. Of course we only scan +/-6% from a nominal kappa=1.65. However, if the dependence were as strong as that for q, the result would be clear. We need to take a closer look at the pedestal widths - it might be possible to pull a more subtle trend from those signals. We were fairly successful in obtaining shots at constant q and triangularity while scanning kappa and Ip. The RF had some difficulty in coupling, but there was probably enough power to trust our conclusions. ================================ Shots suitable for further analysis include: 1000524006 1000524007 start scan to lower kappas 1000524008 1000524009 1000524010 1000524011 1000524012 1000524013 1000524015 1000524016 start scan to higher kappas 1000524017 1000524018 1000524019 1000524020 1000524021 1000524022 |
| Physics Operator Summaries |
| Entered: Jul 7 2004 04:37:11:003PM |
| Author: To Be Determined |
| Physop run summary 1000524: SL Greenwald PO Marmar EO Cochrane MP 232 EDA parameter scans Engineering setup: Overnight ECDC in D2, stopping at 7:30am. Power system setup as on 1000523008 Gas setup - fill B-top 6 psi of D2 Hybrid enabled fill B-side lower 1 psi of Ar Hybrid enabled leave B-side upper as is Hybrid DISABLED fill C-side 30 psi of D2 Hybrid enabled leave J-bottom as is Hybrid DISABLED Main goal for today -- kappa scans at fixed q Results We had many shots with kappa scans and a small range of q95. The range in kappa covered was from 1.5 to 1.78. The machine ran well today. All shots ran through to the end with the exceptions of: 4 -- early disruption after a big injection 5 -- dud (PF breaker pulled before t=0) 14 -- fizzle due to huge gas prepuff from DNB 19 -- Li-Ag-Li pellet at 1.75 sec --> disrupt shortly thereafter The RF started running from shot 6. Scorecard: 1 dud 1 fizzle 20 plasmas ___________ 22 shot cycles |
| Session Leader Comments | |||
| May 24 2000 09:07:03:640AM | Martin Greenwald | PLAN MP 232 Mapping EDA/ELMfree Boundary The purpose of these experiments is to continue the investigations into the scaling of the EDA/ELMfree boundary with the ultimate goal of understanding the physics of EDA. We will also take the opportunity to look for type I ELMs. So far, we have determined that EDA is most likely at lower plasma current ($q_{95} \ge 3.7$), for moderate plasma shaping ($\delta \sim 0.35 - 0.55$) and at high neutral pressures. The degradation in particle confinement that accompanies EDA is correlated with changes in impurity density profiles which are steeper in ELMfree and scale with the parameters listed above. Increased edge fluctuations also accompany EDA. [4] It is worth noting, that theories for ELMs involve the MHD stability of the transport barrier region. Plasma shape - particularly triangularity - is predicted to have a strong effect on that stability. The edge safety factor is also predicted to influence stability[5]. The dependencies that we have observed are superficially consistent with these predictions, but only if we identify EDA as the more stable state. This seems to be contradicted by the edge fluctuations and lower particle confinement that is observed in that regime. We will begin with a kappa scan. Starting at 1.65 and Ip = 1 MA we will scan down to kappa=1.55 and Ip = 0.94 (q ~const). The current will be adjusted up or down in search of the EDA/ELMfree boundary. When this is complete we will reverse the process scanning to higher kappa (~1.75). As time permits, we will begin triangularity scans, following up on 990922 (which had very limited RF power). | |
| May 24 2000 09:24:29:280AM | 1000524001 | Martin Greenwald | No RF (still vacuum conditioning) Decent shot - a few dithers |
| May 24 2000 09:56:02:217AM | 1000524002 | Martin Greenwald | Similar to 001, slightly lower current and kappa still no RF |
| May 24 2000 10:09:16:170AM | 1000524003 | Martin Greenwald | Similar again RF "almost" ready |
| May 24 2000 10:25:15:170AM | 1000524004 | Martin Greenwald | Disruption at 0.5 sec ~ big injection? |
| May 24 2000 10:39:45:700AM | 1000524005 | Martin Greenwald | nil, nada, nothing |
| May 24 2000 11:07:57:623AM | 1000524006 | Martin Greenwald | First shot with RF Decent EDA shape scans not quite what we wanted upper triangularity scanned up to far outer gap went to 0 |
| May 24 2000 11:41:15:827AM | 1000524007 | Martin Greenwald | Substantial kappa scan Halpha drops with kappa but apparently no effect on widths or fluctuations - still in EDA? next shot we go up in current to lower q toward ELMfree |
| May 24 2000 12:00:36:577PM | 1000524008 | Martin Greenwald | lowered q95 a bit some sign of dithering to ELMfree at lower kappa but nothing clear yet |
| May 24 2000 12:18:22:983PM | 1000524009 | Martin Greenwald | The RF power dropped at 1.2 Before that Halpha was dropping and dithering to ELMfree at 1 kHz Pedestal widths don't show that trend |
| May 24 2000 12:39:10:967PM | 1000524010 | Martin Greenwald | three distinct h-modes all seem EDA though radiation rises rapidly raise the current to look for ELMfree |
| May 24 2000 12:57:15:297PM | 1000524011 | Martin Greenwald | big injection early lots of radiation lost one transmitter early |
| May 24 2000 01:25:11:497PM | 1000524012 | Martin Greenwald | ELMfree too much radiation RF has trouble coupling |
| May 24 2000 01:45:56:263PM | 1000524013 | Martin Greenwald | moved rf start time later H-mode only brief again lots of impurity accumulation basically ELMfree with dithers to EDA |
| May 24 2000 01:59:23:780PM | 1000524014 | Martin Greenwald | fizzle |
| May 24 2000 02:24:53:843PM | 1000524015 | Martin Greenwald | Slightly higher q ~ 3.8 Starts EDA, becomes more ELMfree as kappa is scanned down (or as impurities accumulate) |
| May 24 2000 03:01:36:750PM | 1000524016 | Martin Greenwald | start scan to higher kappas constant ip on this shot fairly steady eda vb widths narrow, xrays broader |
| May 24 2000 03:32:16:000PM | 1000524017 | Martin Greenwald | Starting to flatten out q time history multiple h-modes eda seen w/reflectometer |
| May 24 2000 03:30:52:107PM | 1000524018 | Martin Greenwald | q a bit flatter marginal eda elmfree many rf trips, low power |
| May 24 2000 03:50:18:280PM | 1000524019 | Martin Greenwald | Good control of q, delta 3 H-mode phases, each eda good eda/elmfree dithering 1.3-1.35 sec |
| May 24 2000 04:16:29:450PM | 1000524020 | Martin Greenwald | right gap bigger - oops try for smaller gap next time marginally eda/elmfree again - no sign of change with kappa |
| May 24 2000 04:33:40:840PM | 1000524021 | Martin Greenwald | smaller gap helped rf still marginal eda/elmfree multiple h-modes |
| May 24 2000 04:56:07:030PM | 1000524022 | Martin Greenwald | slightly lower current q95 slightly greater than 1 clear EDA throughout - lousy confinement no obvious effect of elongation |
| Physics Operator Comments | |||
| May 24 2000 08:51:20:717AM | Earl Marmar | Run plan for 1000524: SL Greenwald PO Marmar MP 232 EDA parameter scans Engineering setup: Overnight ECDC stopping at 7:30am. Power system setup as on 1000523008 Gas setup - fill B-top 6 psi of D2 Hybrid enabled fill B-side lower 1 psi of Ar Hybrid enabled leave B-side upper as is Hybrid DISABLED fill C-side 30 psi of D2 Hybrid enabled leave J-bottom as is Hybrid DISABLED | |
| May 24 2000 08:51:40:843AM | Earl Marmar | coldstart; all matrices respond; no errors | |
| May 24 2000 09:33:10:763AM | 1000524001 | Earl Marmar | reload 1000523008 increase TF to 5.4 from 5.3 T no RF for this shot plasma |
| May 24 2000 09:51:06:357AM | 1000524002 | Earl Marmar | reduce clearin, zxu and rcur to reduce kappa, reduce I_p to keep q95 roughly constant plasma not aggressive enough; got q95~1.6 |
| May 24 2000 10:08:01:577AM | 1000524003 | Earl Marmar | scan kappa during shot (0.7 to 1.5) plasma kappa was constant (RCUR needs to increase during scan) |
| May 24 2000 10:32:52:843AM | 1000524004 | Earl Marmar | more aggressive on ZXU Ramp RCUR out during shot (5 mm) plasma big injection at 0.51, then disrupt |
| May 24 2000 10:42:23:950AM | 1000524005 | Earl Marmar | no PCS changes Should be some RF on this one Dud PF breaker pulled before the shot |
| May 24 2000 11:17:15:967AM | 1000524006 | Earl Marmar | no PCS changes plasma outer gap got a bit too small (0 according to efit) Kappa did get below 1.55 q_95 increased and upper triangularity also increased |
| May 24 2000 11:38:28:107AM | 1000524007 | Earl Marmar | Increase ZXU, increase RXU, eliminate Ip scan, decrease ZCUR during shot decrease argon pulse width plasma close on the kappa scan; overcompensated on upper triangularity; outer gap looks ok q_95 is scanning some |
| May 24 2000 12:03:19:547PM | 1000524008 | Earl Marmar | B_R offset decreased by .0005 Tesla tweak RXU decrease RCUR at 0.7 seconds to increase early kappa I_p up to 1.03 from 1.00 MA RF programmed to stay on at 2 MW until 1.5 seconds plasma |
| May 24 2000 12:23:31:200PM | 1000524009 | Earl Marmar | extend current flattop to 1.6 seconds increase I_p during TF waggle, to keep q_95 more constant plasma some RF trips |
| May 24 2000 12:50:57:077PM | 1000524010 | Earl Marmar | slight tweaks to I_p and RXU plasma |
| May 24 2000 01:08:38:670PM | 1000524011 | Earl Marmar | increase I_p by 5% plasma RF down to 1 MW at .88 seconds looks like we're hitting the PLC limit on EF1U at end of flat-top |
| May 24 2000 01:38:29:357PM | 1000524012 | Earl Marmar | no PCS changes plasma |
| May 24 2000 01:38:52:433PM | 1000524013 | Earl Marmar | no PCS changes delay RF turn-on plasma |
| May 24 2000 02:08:08:123PM | 1000524014 | Earl Marmar | reload shot 10 fizzle very high fill pressure something puffed before -4 seconds (DNB?) |
| May 24 2000 02:34:08:250PM | 1000524015 | Earl Marmar | add 2 msec to prepuff close DNB gate valve plasma; slight hesitation during current rise |
| May 24 2000 03:01:00:980PM | 1000524016 | Earl Marmar | try for increasing elongation move plasma up instead of down keep outer gap roughly constant; grow inner gap a little add 2msec to prepuff plasma got the elongation to 1.75 at 1.6 seconds |
| May 24 2000 03:32:56:250PM | 1000524017 | Earl Marmar | tweak I_p to keep q_95 steadier move RXU out to reduce upper triangularity plasma |
| May 24 2000 03:33:51:153PM | 1000524018 | Earl Marmar | RXU further out plasma better control of upper triangularity |
| May 24 2000 03:55:54:200PM | 1000524019 | Earl Marmar | Reduce I_p by 5% RXU a little further out plasma |
| May 24 2000 04:13:26:013PM | 1000524020 | Earl Marmar | B_R offset increased by 0.5 mT increase clearin 5 mm to increase left gap increased right gap as well plasma |
| May 24 2000 04:40:56:373PM | 1000524021 | Earl Marmar | increase RCUR 4 mm to shrink right gap plasma |
| May 24 2000 04:56:00:577PM | 1000524022 | Earl Marmar | reduce I_p 5% reduce outer gap 2 mm plasma |
| Engineering Operator Comments | ||||
| Shot | Time | Type | Status | Comment |
| 1 | 09:08:21:170AM | Plasma | Ok | |
| 2 | 09:33:00:047AM | Plasma | Ok | |
| 3 | 09:54:09:797AM | Plasma | Ok | |
| 4 | 10:15:15:513AM | Plasma | Ok | |
| 5 | 10:37:00:200AM | Plasma | Bad | Comm fault OH2L |
| 6 | 10:55:32:763AM | Plasma | Ok | |
| 7 | 11:18:20:077AM | Plasma | Ok | |
| 8 | 11:41:47:403AM | Plasma | Ok | |
| 9 | 12:04:11:310PM | Plasma | Ok | |
| 10 | 12:26:34:797PM | Plasma | Ok | |
| 11 | 12:50:04:030PM | Plasma | Ok | |
| 12 | 01:11:33:263PM | Plasma | Ok | |
| 13 | 01:34:45:280PM | Plasma | Ok | |
| 14 | 01:56:53:873PM | Plasma | Ok | |
| 15 | 02:15:59:030PM | Plasma | Ok | |
| 16 | 02:40:48:187PM | Plasma | Ok | |
| 17 | 03:01:45:467PM | Plasma | Ok | |
| 18 | 03:21:52:920PM | Plasma | Ok | |
| 19 | 03:43:48:750PM | Plasma | Ok | |
| 20 | 04:04:55:890PM | Plasma | Ok | |
| 21 | 04:25:29:717PM | Plasma | Ok | |
| 22 | 04:47:47:310PM | Plasma | Ok | |