| Miniproposals | ||||||||||
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| Operators | |
| Session leader(s): | Dennis Whyte |
| Physics operator(s): | Robert Granetz |
| Engineering operator(s): | Andy Pfeiffer,Bill Byford |
| Engineering Operator Run Comment |
| MP484: Development of discharges that minimize boron erosion Session lea |
| Session Leader Plans |
| Entered: Jan 22 2008 09:19:15:780AM |
| Author: Dennis Whyte |
| Objectives:
--------------- Develop discharges that optimize recovery ICRH recovery after boronizations, while minimizing boron film erosion. The basic strategy is to use "atypical" plasma shapes post boronization in order to avoid eroding boron in the important locations for Mo sources in typical H-mode plasmas. The plasma shape will be LSN with high triangularity and ~ 1 cm outer gaps: this sets flux surfaces that are connected to ICRH down on the horizontal target in the outer divertor. Hopefully we will also learn something about erosion locations, since we have the capability S3 to measure the boron deposition profile. Machine requirements: ------------------------------- - between shot boronization available with following parameters: foreline pressure 50 mTorr, 10% diborane, vertical field at 10% of Bt (I_EF ~ 200 A), EC resonance location R=70 cm (fixed). - heating: up to 3.5 MW of ICRH - plasma shots: 0.9 - 1 MA, B=5.4 T, D2 Reference discharges: ------------------------------- Ref. A: Standard triangularity LSN H-mode shots: 1080103019 + 2.5 MW ICRH 0.75 - 1.4 s Ref B: High-triangularity JFT2M shape: 1080108013 + 2.5 MW ICRH 0.75 - 1.4 s Ref C: USN 1 MA 1080116003 + 2.5 MW ICRH 0.75 - 1.4 s Diagnostics ---------------- Standard diagnostics, with emphasis on Mcpherson and Chromex S3 will have it gate valve open and park the head near the vessel entrance. Will be used in some BZN's to document deposition rate pattern. Probe to be kept in Isat at all times to inhibit film growth on probe. Shot plan -------------- 1. Establish fiducial shots for 2 reference discharges without BZN + develop ICRH tuning. Diborane bottle closed in case cell access required for ICRH or diagnostics Minimum 2 shots. 2. Perform first between shot boronization (open diborane bottle) Insert S3 for diagnosis of depostion profile. Run 2 Ref. A discharges to document the evolution of Mo and plasma performance, dPrad/dt, etc. 3. Repeat between shot boronization Run 2 Ref. B discharges with approx. same RF energy throughput as in part 2. Run 1 Ref. A discharges and document evolution. 4. Repeat between shot boronization 2 Ref B 2 Ref A 4. Repeat 2-3 with R_EC at 80 cm and/or change boronization pressure to optimize deposition rate or try USN auxiliary plan ------- If we find type I ELMs affecting the Ref. B shots, we may attempt to turn on error field correction coils to modify or eliminate ELMs. This may be worth a try since the ELMs were limiting RF throughput in th 1080108 run. |
| Physics Operators Plans |
| Entered: Jan 21 2008 01:40:54:620PM |
| Author: Robert Granetz |
Engineering setup for Tuesday 22 Jan 2008
MP484: Development of discharges that minimize boron erosion
Session leader: Whyte
Physics operator: Granetz
ECDC overnight in D2 and bake at 60 C.
Run will start at 09:00 and end at 17:00.
Power systems as on 1080108006.
*** NOTE: WE WILL WANT TO DO BETWEEN-SHOT BORONIZATION DURING THIS RUN,
POSSIBLY STARTING IMMEDIATELY AFTER THE FIRST SHOT ***
A-coil configuration: +Dtop -Dbot -Jtop +Jbot; Enabled (standard
configuration)
Gas Setup:
fill B-Top with 6 psi D2 Hybrid enabled (PG4)
fill B-side lower with 1 psi Ar Hybrid DISABLED (PG1)
leave B-side upper as is Hybrid DISABLED (PG2)
fill B-main (C-side) with 40 psi D2 Hybrid enabled (PG3)
leave NINJA as is DISABLED
Enable the following gate valves and shutters, assuming no vacuum problems:
ECE, VUV, Z-bolo, DNB
Torvac setup: keep gate valves open
Specific diagnostics: surface science station (S3)
-------------------------------------------------------------------------------
ICRF Setup: all transmitters in run-on by 08:30
LH Setup: no
DNB: yes, 7 x (100 ms on / 100 ms off)
Cryopump: yes, although it may not be needed for the first shot
-------------------------------------------------------------------------------
Run plan: Load all segments, including the startup segment, from
1080108006, which had the outer separatrix leg going down the
slot to the horizontal plate, a la JFT-2M. (The startup from the
most recent run was not a normal one, so I don't want to use it.)
We will want to do between-shot boronization during this run,
possibly starting immediately after the first shot.
|
| Session Leader Summaries |
| Entered: Jan 22 2008 05:29:31:670PM |
| Author: Dennis Whyte |
| Off to a slow start this morning. Computer problems stopped
us from getting plasma until about noon, and ICRH data acq. glitch slowed us down for another hour in the afternoon. On the positive side we got through the first part of our run plan. We established fiducial shots without BZN and we got nice S3 data on the BZN profile (~0.7 nm/s peak deposition rate 5-10 cm outboard of the R=70 cm resonance). We then got two between shot boronizations. Post BZN#1: In the standard LSN shape the BZN effect lasted less than one shot, with very "discrete" radiation increases (uncertain what all of these are). Second shot had ELM-free H-modes with high radiation Post BZN#2: We ran JFT2m shape. The performance of those H-mode also degraded in ~1 shot. The first shot had a decent quiescent H-mode, but the second post-BZN shot was nearly identical to the non-BZN fiducial. Last shot of the day, we went back to standard LSN shape to see if our two JFT2M shots "saved" the BZN film in the important spots. The definite answer is no. Shot 17 (3rd shot after 2nd BZN) had multiple ELM-free H-modes and marginal to no improvement compared to non-BZN fiducial. Based on this preliminary assessment, the technique to save BZN films by using non-standard shapes did not work. This must be telling us something important about the critical erosion/Mo source regions, but still not clear what the message is. |
| Physics Operator Summaries |
| Entered: Jan 22 2008 04:47:42:827PM |
| Author: Robert Granetz |
| Run summary for Tuesday 22 Jan 2008 MP484: Development of discharges that minimize boron erosion Session leader: D. Whyte Physics operator: R. Granetz We lost the entire morning to problems with node CMODA (old VMS node), which Josh had to eventually get the MDS cycle to work around. The first plasma shot occurred around noontime. We also lost a significant amount of time to getting the first between-shot boronization going, due to a problem with the diborane piezo valve. And there were also a few fizzles as the startup conditions changed due to boronizations. There was also an IOC fault on EF1 on shot 15, and ICRF data acquisition failed on shots 12 and 16. Due to all of these difficulties, we only got 9 plasmas, some in the JFT-2M configuration, and some in the standard 1 MA LSN configuration. ICRF power was 2.5 MW on all shots, with some shots having more faults than others. See the session leader's run summary for results on the boronization issues. Scorecard: 9 plasmas 0 duds 3 fizzles 0 power supply tests 6 no-power MDS shot cycles -------------- Total: 18 shot cycles; The total number of shot cycles doesn't match the final shot number on the big board (17) because shot 4 occurred twice. |
| Session Leader Comments | |||
| Jan 22 2008 11:59:24:573AM | 1080122006 | Dennis Whyte | First plasma shot of day.
1 MA, LSN, 2.5 MW RF (some trips) 7 ELM free H-modes (as expected far away from last BZN) L-mode dPrad/dt: 1.2 MW/s H-mode init dPrad/dt: 7 MW/s Peak Prad ~ 1.9 MW Peak Wtot ~ 114 MJ Will tweak tuning for ICRH in next shot. |
| Jan 22 2008 12:12:22:777PM | 1080122007 | Dennis Whyte | 1 MA, LSN, 2.5 MW RF better tuning than last shot
7 ELM free H-modes L-mode dPrad/dt: 1.2 MW/s L-mode Prad ~ 0.64 MW H-mode init dPrad/dt: 8 MW/s Peak Prad ~ 2.6 MW Peak Wtot ~ 114 MJ |
| Jan 22 2008 12:19:26:427PM | 1080122008 | Dennis Whyte | Dud because cryopump burped before shot and fill
was too strong. Will heat up cryo for rest of day for better repeatability. |
| Jan 22 2008 12:54:31:433PM | 1080122009 | Dennis Whyte | 1 MA, JFT2M shape, 2.5 MW RF for ICRH tuning
some trips in ICRH, will repeat for ~ 12 ELM free H-modes L-mode dPrad/dt: 5.3 MW/s L-mode Prad ~ 0.34 MW H-mode init dPrad/dt: 8.9 MW/s Peak Prad ~ 2.8 MW Peak Wtot ~ 107 MJ |
| Jan 22 2008 12:58:22:080PM | 1080122010 | Dennis Whyte | 1 MA, JFT2M shape, 2.5 MW RF for ICRH tuning
ICRH tuning improved from last shot with relatively steady 2.5 MW ICRH trips not clearly related with ELMs? ~ 12 ELM free H-modes L-mode dPrad/dt: N/A since H-mode comes in so fast L-mode Prad N/A H-mode init dPrad/dt: 10 MW/s Peak Prad ~ 2.8 MW Peak Wtot ~ 110 MJ |
| Jan 22 2008 01:57:13:070PM | 1080122011 | Dennis Whyte | 1 MA, standard LSN shape, 2.5 MW RF for ICRH tuning
following 10 minute BZN, Rec=70cm, P=50 mTorr S3 inserted for radial BZN scan showing peak deposition rate ~ 0.7 nm/min Fizzle |
| Jan 22 2008 03:24:21:217PM | 1080122012 | Dennis Whyte | 1 MA, standard LSN shape, 2.5 MW RF
following 10 minute BZN, Rec=70cm, P=50 mTorr S3 inserted for radial BZN scan showing peak deposition rate ~ 0.7 nm/min + 1 fizzle 2 EDA H-modes ICRH did well ~ 2.5 MW L-mode dPrad/dt: ~ 0 L-mode Prad: 0.23 H-mode init dPrad/dt: 4.1 MW/s Peak Prad ~ 2.8 MW Peak Wtot ~ 143 MJ *** Peak Prad is so high because at 0.836 s (in the first EDA) there is a step-wise increase in radiate power according to 2pi diode (and a slightly smaller step at .695 s in the first EDA and a smaller step yet at 1.143 s in the second EDA). This is a very funny "injection" since there is no immediate response in density or central SXR. Is this the sign that the B film is being removed in a discrete event? The Mo signal starts to increase after this event. |
| Jan 22 2008 03:33:04:460PM | 1080122013 | Dennis Whyte | 1 MA, standard LSN shape, 2.5 MW RF
2nd shot following 10 minute BZN, Rec=70cm, P=50 mTorr 3 ELM free H-modes ICRH 2,5 MW L-mode dPrad/dt: ~ 1.2 L-mode Prad: 0.347 H-mode init dPrad/dt: 5.3 MW/s Peak Prad ~ 2.8 MW Peak Wtot ~ 133 MJ *** Despite Mo source being "worse" there were no steps in Prad. Also, QC-mode seems to appear in magnetic fluctuations. |
| Jan 22 2008 04:14:04:900PM | 1080122015 | Dennis Whyte | 1 MA, JFT2M shape, 2.5 MW RF
ICRH tuning on J was not optimal so we dropped a few MW. Disrpution in current rampdown ~ What appears to be EDA H-mode, however get the low (50 kHz) and high (800 kHz) poorly coherent fluctuations that dont' look exaclty like QC mode. L-mode dPrad/dt: N/A since H-mode comes in so fast L-mode Prad N/A H-mode init dPrad/dt: N/A due to discrete steps in diode Peak Prad ~ 1.4 MW Peak Wtot ~ 115 MJ Prad had steps as in previous post-BZN (shot 12) but of much smaller magnitude. |
| Jan 22 2008 04:54:28:380PM | 1080122016 | Dennis Whyte | 1 MA, JFT2M shape,
We lost data acq. on D and E. J did not work. BAsed on radiated power comparisons with #10 I'd guess we got D and E at full power. 2nd shot after BZN. ~10 ELM-free H-modes L-mode dPrad/dt: N/A since H-mode comes in so fast L-mode Prad N/A H-mode init dPrad/dt: ~5 (many discrete steps) Peak Prad ~ 2.0 MW Peak Wtot ~ 85 MJ |
| Jan 22 2008 05:18:48:267PM | 1080122017 | Dennis Whyte | 1 MA, LSN standard shape, 2.5 MW ICRH.
3rd shot after BZN, but after 2 shots with high-tri shape. ~7 ELM-free H-modes L-mode dPrad/dt: 2 L-mode Prad: 0.405 H-mode init dPrad/dt: 7 Peak Prad ~ 2.5 MW Peak Wtot ~ 119 MJ |
| Physics Operator Comments | |||
| Jan 22 2008 09:13:37:133AM | Robert Granetz | Load seg 1, 2, 4 from 1080108006 (JFT-2M shape). Load seg 3 from seg 2 of 1080103019 (a typical 1 MA, 5.4 T, LSN). Reload seg 2 from seg 2 of 1080108013 (JFT-2M shape), as per SL's run plan. Reload seg 4 from seg 4 of 1080116003 (USN), as per SL's request. | |
| Jan 22 2008 09:20:25:953AM | 1080122001 | Robert Granetz | Shot 01 -- Aborted. There is a problem with cryopump valve. It will be on for the first shot, and maybe for all the shots, since the valve can't be closed for some reason. I have therefore added 15 ms to pre-fill (to 34 ms) to compensate for cryopumping. Power room access for ICRF. Next shot: normal 1 MA, 5.4 T, LSN with ICRF |
| Jan 22 2008 09:47:17:500AM | 1080122001 | Robert Granetz | We're having a long hold while Josh works on something. |
| Jan 22 2008 09:48:40:487AM | 1080122002 | Robert Granetz | Shot 2 -- No-power shot due to MDS problems. Next shot: try again for standard 1 MA LSN w/ICRF. |
| Jan 22 2008 10:17:37:567AM | 1080122002 | Robert Granetz | Another long delay for Josh to sort out MDS problems. |
| Jan 22 2008 10:35:50:760AM | 1080122003 | Robert Granetz | Shot 03 -- No-power shot due to MDS problems. Josh is still working on it. Next shot: keeping my fingers crossed |
| Jan 22 2008 10:57:49:987AM | 1080122004 | Robert Granetz | Shot 04 -- No-power shot due to MDS problems. Josh is still working on it. Next shot: who knows? |
| Jan 22 2008 11:17:15:697AM | 1080122004 | Robert Granetz | Shot 04 (again) -- No-power shot...how surprising. This is the 2nd ""shot 04"". Actually, it came up on the big board as shot 03. Next shot: I don't even know what the shot number will be. |
| Jan 22 2008 11:39:11:613AM | 1080122005 | Robert Granetz | Shot 05 -- No-power shot. Next shot: plasma, according to Josh |
| Jan 22 2008 11:54:21:710AM | 1080122006 | Robert Granetz | Shot 06 -- Plasma. Good shot. Typical 1 MA, 5.4 T, LSN. Prf=2.5 MW. Lots of short ELM-free H-modes. Interesting particulate injection late in the shot. Next shot: repeat to better tune the RF |
| Jan 22 2008 12:05:50:207PM | 1080122007 | Robert Granetz | Shot 07 -- Plasma. Good shot. Standard 1 MA LSN. 2.5 MW of RF, similar performance as on the previous shot. Not a very good startup because the pre-fill pressure dropped by a factor of 2 for some reason. Next shot: Switch to JFT-2M shape (outer strikepoint down the slot on the floor). Also add 4 ms to pre-fill. The cryopump will continue to stay on for the remainder of the day because their shutoff valve won't close. |
| Jan 22 2008 12:17:28:703PM | 1080122008 | Robert Granetz | Shot 08 -- Fizzle because the cryopump wasn't pumping well before the shot. Sine the pump apparently is not going to be reproducible we'll have sort of turn it off by bleeding helium gas through it continously for the remainder of the day. Next shot: try again with cryopump effectively disabled this time |
| Jan 22 2008 12:35:14:507PM | 1080122009 | Robert Granetz | Shot 09 -- Plasma. Good shot. 0.9 MA, JFT-2M shape. Prf=2.5 MW. Good startup. Next shot: Repeat for RF. Also reduce pre-fill by 5 ms. |
| Jan 22 2008 01:09:51:123PM | 1080122010 | Robert Granetz | Shot 10 -- Plasma. Good shot. 0.9 MA, JFT-2M shape. Prf=2.5 MW with only a few faults. Pause for between-shot boronization (first one today) with the following parameters: 10% diborane Foreline pressure: 50 mTorr Vertical field at 10% of Bt (I_EF ~ 200 A) EC resonance located at R=70 cm (fixed) Next shot: back to standard 1 MA LSN. Also reduce pre-fill by 6 ms (27 ms) |
| Jan 22 2008 01:26:46:503PM | 1080122010 | Robert Granetz | The piezo valve on the boronization system is not opening for some reason. We'll have to close the diborane bottle and check it out. |
| Jan 22 2008 01:36:25:450PM | 1080122010 | Robert Granetz | Okay, the engineers finally got the valve to open by remote control, so no cell access is required. We're doing the first between-shot boronization now. |
| Jan 22 2008 01:57:17:443PM | 1080122011 | Robert Granetz | Shot 11 -- Fizzle. Pre-fill pressure was 0.08 mTorr, so it should have been okay. Next shot: decrease pre-fill another 4 ms. |
| Jan 22 2008 02:31:06:450PM | 1080122012 | Robert Granetz | Shot 12 -- Plasma. Good shot...just as a large tour group came through. Standard 1 MA LSN. Two long H-modes. ICRF data is missing...may be recoverable. Good startup. Next shot: repeat, no changes except turn on 100 ms argon puff. |
| Jan 22 2008 03:03:49:567PM | 1080122012 | Robert Granetz | We're having a long break while Josh tries to get the ICRF cPCI systems working again. |
| Jan 22 2008 03:24:47:373PM | 1080122013 | Robert Granetz | Shot 13 -- Plasma. Good shot. Standard 1 MA LSN w/ 2.5 MW of ICRF. Three H-modes. Between-shot boronization being done after this shot. 10 minutes, w/EF4. Next shot: switch back to the JFT-2M equilibrium |
| Jan 22 2008 03:48:38:887PM | 1080122014 | Robert Granetz | Shot 14 -- Fizzle. Next shot: reduce pre-fill another 2 ms. |
| Jan 22 2008 04:15:49:637PM | 1080122015 | Robert Granetz | Shot 15 -- Plasma. JFT-2M shape. Disrupted at t=1.5 s during the current rampdown. Prf=2.5 MW with some faulting. One long steady (EDA?) H-mode. I think the disruption was due to a vertical instability. We got an IOC fault on EF1, and we'll close the diborane bottle so that the fuses can be checked out. This means that we won't be doing any more between-shot boronizations today. Next shot: repeat |
| Jan 22 2008 04:46:59:607PM | 1080122016 | Robert Granetz | Shot 16 -- Plasma. Good shot. JFT-2M shape. RF data acquisition failed again. Next shot: switch back to the standard 1 MA LSN configuration. Also switch argon puff to PG2 (B-side-upper) because no sign of argon is being seen by our spectroscopists. |
| Jan 22 2008 04:45:03:933PM | 1080122017 | Robert Granetz | Shot 17 -- Plasma. Good shot. Standard 1 MA LSN configuration. Prf=2.5 MW. End of run. |
| Engineering Operator Comments | ||||
| Shot | Time | Type | Status | Comment |
| 1 | 09:14:16:010AM | Plasma | Bad | camac server failure |
| 2 | 09:51:04:800AM | Test | Bad | |
| 3 | 10:32:35:677AM | Test | Bad | |
| 4 | 11:27:41:757AM | Test | Ok | |
| 5 | 11:34:29:513AM | Test | Ok | No Power test |
| 6 | 11:46:14:577AM | Plasma | Ok | |
| 7 | 11:59:53:387AM | Plasma | Ok | |
| 8 | 12:13:05:997PM | Plasma | Ok | |
| 9 | 12:27:14:327PM | Plasma | Ok | |
| 10 | 12:39:50:387PM | Plasma | Ok | |
| 11 | 01:54:26:800PM | Plasma | Ok | |
| 12 | 02:08:07:817PM | Plasma | Ok | |
| 13 | 03:18:15:693PM | Plasma | Ok | |
| 14 | 03:45:04:380PM | Plasma | Ok | |
| 15 | 03:57:31:833PM | Plasma | Ok | |
| 16 | 04:38:36:663PM | Plasma | Ok | |
| 17 | 04:59:04:777PM | Plasma | Ok | |
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