| Miniproposals | ||||||||||
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| Operators | |
| Session leader(s): | Jim Terry |
| Physics operator(s): | Robert Granetz |
| Engineering operator(s): | Sam Pierson,Bill Byford,Bill Parkin |
| Engineering Operator Run Comment |
| MP #426 Large ELM's study EO Pierson PO Granetz SL Terry |
| Session Leader Plans |
| Entered: Jun 28 2005 08:45:32:137AM |
| Author: Jim Terry |
| This experiment (part of MP #426) aims to study large ELMs on C-Mod in terms of their access
conditions and their spatial structure in order to gain a physical understanding of the responsible instability and connect to results on other experiments. It has recently become clear through improved imaging diagnostics that ELMs can have a complicated 3-D structure and that one ELM is actually multiple filaments of enhanced energy and density, eg. as seen on MAST, ASDEX Upgrade. ELMs are thus similar in some respects to blobs seen in the SOL. Although large discrete ELMS have been rare in C-Mod, large, discrete, ELMs did appear in two experiments in the 2004 campaign. One example was the JFT2M comparison experiment, with a shape matching that of JFT2M (eg. Shots 1040416024, 26). The other was a threshold vs configuration experiment in which discharges were limited on the inner nose (eg. 1040325033). The JFT2M type shots were reproduced on 1050623 (e.g. 1050623033) with discrete ELMs appearing soon after the transition to H-mode. Images of the ELM effect on edge D_alpha were captured with the PSI5 camera. We will attempt more imaging of the ELMs in this run, using both the PSI5 300-frame fast camera (imaging the outboard edge) and the PSI4 28-frame fast camera (imaging the wide-angle view from B-side). Setup: No overnight ECDC NINJA fill with 12 psi D2 Load shot 1040325033 - limited on the inner nose RF 0N at 0.7s with 1MW ramping to 3 MW by 1.2 s, OFF at 1.2 s. NINJA puff at A-B lim Run Plan: 1. After loading limited shot 1040325033, observe H-mode type and (hopefully) ELMs. (2 shots) 2. Scan target nel slightly downward (3-4e19 m-2) to see if ELMs appear, change or disappear. (2 shots). 3. Repeat with slightly higher nel (6-7e19 m-2). (2 shots) 4. CONTINGENCY: If ELMs are smaller than those produced on 1050623033, then return to shot conditions of 1050623033. 5. Assuming large ELMs have been seen on one or more of above, go to condition which produced largest, most distinct ELMs, remove RF power ramp and repeat several times, until fast GPI cameras and Edge TS have sufficient data. (10 shots). 6. Start shape scan, progressively moving x-point down and out. Monitor ELM behaviour. If time permits, also increase elongation. (How close to "normal" X-pt location and shape can we get and still see large ELMs?). (8 shots). Key Diagnostics: GPI cameras (PSI5 and PSI4), ECE, Edge TS, D_alpha arrays, edge SXR, PCI, reflectometry, divertor probes, in "fixed" mode, fast magnetics. |
| Physics Operators Plans |
| Entered: Jun 27 2005 10:38:12:270PM |
| Author: Robert Granetz |
| Engineering setup for Tuesday, 28 June 2005
MP #426 -- Study large ELMs Session leader: J. Terry Physics operator: R. Granetz No overnight ECDC, but bake at 60 C. Run begins at 09:00 and ends at 17:00. Power systems as on 1040325033 (0.8 MA, 5.4 T, inboard nose limited) A-coil configuration: normal [+Dtop -Dbot -Jtop +Jbot] and enabled. 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 with whatever Hybrid disabled fill B-main (C-side) with 30 psi He Hybrid enabled (PG3) fill NINJA with 12 psi D2 Enabled Enable the following gate valves and shutters, assuming no vacuum problems: ECE, VUV, Z-bolo shutters Important Diagnostics: GPI cameras, ECE, Edge TS, D_alpha arrays, edge SXR, PCI, reflectometry, divertor probes (in fixed mode), fast magnetics ------------------------------------------------------------------------------- ICRF Setup: RF ready to go on first shot. RF to turn on at t=0.7 s with 1 MW, ramping to 3 MW by 1.2 s. Turn of at t=1.2 s. ------------------------------------------------------------------------------- Run plan: Run inboard-nose-limited plasmas, which exhibited large ELM's in a past run. Use fast cameras and other edge diagnostics to get detailed information on spatial structure in order to understand the instability responsible. |
| Session Leader Summaries |
| Entered: Nov 2 2005 01:56:54:617PM |
| Author: Jim Terry |
| 1050628 Run Summary (part of MP #426)
We accomplished most of what we set out to do. The major results are: 1) the JFT2M shape was better than the "inner nose limited" shape for obtaining discrete ELMs. (See MP 426 for a figure showing these shapes.) Although we hoped to create large ELMs, these were not really large, but were discrete and repetitive. 2) A complicated ELM structure is seen in the fast-diode array data as well as in the outboard edge movie images, although the movie images are not as bright as desired and do not have the desired spatial resolution. In the SOL the ELM looks like a large blob with fine structure. Fast-diodes see a coherent ELM precursor on the views inboard of the separatrix (e.g. 014 at 0.9284 and 0.955 s) 3) There was no large scale spatial structure (i.e. filaments) observed with the wide-angle-view movies. Nonetheless, with this view changes on a ~2 microsec timescale were observed in the emission coming from the lower inner wall/divertor region. 4) When the X-pt was moved outboard in steps from its optimal (for ELMs) location of (R_L,Z_L)=(51.1,-36.7)cm to a more typical (55.0,-37.5) cm, then "ELM" duration increased from ~60 microsec to ~4 msec. The long duration "ELMs" are better described as H-to-L back transitions. (shots 024-026). This raises the question: Why is the ELM nature so shape dependent? Is triangularity the key parameter? 5)The ELMs were most apparent when the density was just above the low density H-mode threshold. In fact, on shot 017 no H-mode was produced. On that shot the pre-RF density was nl_04=4e19 m-2, while the target densities for the H-mode shots were typically 5e19 m-2. 6)Edge TS reported very hot edge pedestal temperatures ~1 keV which decayed relatively quickly, possibly due to the density increase due to the H-mode. The H-mode density typically reached nl_04=1e20 m-2. (The NINJA gas puff used for the GPI increased the density by ~1e19, see shot 017 at .68 s.) 7)The outermost channel of the GPC observed a ~15% temperature perturbation from the ELM. GPC2 was not operational. Shot list: 001 - High current disruption, not what was desired. 002 - ELMs after 1.1 s - PSI5 trigger probably at 1.19 s, not ELM triggered; PSI4 images are black 003 - ELMs after 0.79 s - PSI5 triggered at 0.72 s on noise, not ELM triggered; PSI4 images are black 004 - ELMs after 0.827 s - PSI5 triggered at 0.827s on ELM ; PSI4 images are black 005 - H-modes but no ELMs - neither camera triggered 006 - dud 007 - H-mode but no ELMs - PSI5 triggered at 0.85s on back transition; PSI4 images are black 008 - H-mode but no ELMs - PSI5 triggered at 0.783s on back transition; PSI4 images are black 009 - disrupted early (brick) 010 - long duration ELMs or dithers after 0.996 s - PSI5 triggered at 0.75s on noise; PSI4 images are black 011 - dud 012 - limit plasma hard on inner nose; long duration ELMs or dithers - PSI5 triggered at 0.906s on "ELM"; PSI4 no data 013 - limit plasma harder on inner nose; still long duration ELMs or dithers - PSI5 triggered at 0.905s on noise; PSI4 saturated at 1 ms/frame 014 - changed to JFT2M shape; PSI5 and PSI4 (4 microsec) triggered at 0.727s, but not really on an ELM; ELMs much better in this shape; great data on fast-diodes see coherent precursor 015 - PSI4 (10 microsec - 4 post trigger samples) triggered at 0.953 s on 1st ELM ; PSI5 didn't trigger 016 - PSI5 and PSI4 triggered at 0.997 s on ELM ; great data on fast-diodes see coherent precursor see 1.012 s. 017 - no H-mode - probably below low density threshold, cameras triggered at 0.905s 018 - PSI5 and PSI4 triggered at 0.9125 s on second of a pair of ELMs; clear change in PSI4 images; clear ELM propagation on diodes 019 - PSI5 and PSI4 triggered at 1.07 s a single ELM; clear change in PSI4 images -very good 020 - dud 021 - PSI5 and PSI4 triggered at 0.938 s a single ELM; clear change in PSI4 (4 microsec) images 022 - PSI5 and PSI4 triggered at 0.908 s a single ELM; clear change in PSI4 (2 microsec) images 023 - PSI5 and PSI4 triggered at 0.918 s a single ELM; clear change in PSI4 (2 microsec) images - outer gap changed from 1.5 to 1.8 cm for this and all following shots 024 - PSI5 and PSI4 triggered at 0.925 s a single ELM; clear change in PSI4 (4 microsec) images 025 - moved RXL out by 2 cm; big change in the ELMs which are now longer and are not sharp spikes, but are flat on top; PSI5 and PSI4 triggered at 0.920 s during an "ELM" or back transition, both missed the "ELM" crash; PSI4 is saturated 026 - moved RXL out by another 2 cm to 55.0 cm; change in the "ELMs" which are now back transitions that last ~5 ms; PSI5 and PSI4 triggered at 0.913 s during a back transition, both missed the transition. 027 - moved RXL 0.5 cm inside of JFT2M position 50.5cm; PSI5 and PSI4 triggered at 0.909 s on a single ELM 028 - moved RXL back to JFT2M position 51.1cm; PSI5 and PSI4 triggered at 0.905 s during multiple ELMs; no distinct ELM 029 - PSI5 and PSI4 triggered at 0.929 s on single ELM 030 - ELMs appear to be degrading; PSI5 and PSI4 triggered at 0.915 s on noise 031 - PSI5 triggered at 0.923 s on the second of an ELM pair; PSI4 didn't trigger |
| Physics Operator Summaries |
| Entered: Jun 28 2005 09:05:15:433PM |
| Author: Robert Granetz |
| Physop summary for Tuesday 28 June 2005: MP #426 -- Study large ELMs Session leader: J. Terry Physics operator: R. Granetz The tokamak ran very well today, and so did the RF when is was programmed to ramp power from 1 to 3 MW (E and J). For the first half of the day we ran an inboard-nose-limited plasma, but these did not exhibit clear ELMs (unlike last year). The 2nd half of the day was spent running the recent JFT-2M equilibrium, with some variation of x-point location, density, and RF waveforms. These were basically ELMy, but read Jim Terry's session summary to learn more of the details. We had lots of new data from fast framing cameras and from an IR camera, along with probe data, edge TS, etc. Startup reliability was very good. There were no computer problems or power supply problems. There were a number of cell accesses, mostly to work on triggering issues with the IR camera. Scorecard: 28 plasmas 0 fizzles 3 duds 0 tests or no-power shot cycles ---------- 31 total shot cycles |
| Session Leader Comments | |||
| Jun 28 2005 09:36:36:420AM | 1050628001 | Jim Terry | No NINJA puff on this shot
6810 digitization freq is to 500 kHz triggering at 0.7 s Setup to trigger the PSI5 and PSI4 with the ELM trigger. ELM trigger gate is 0.705 to 1.2 s Hard trigger at 1.19 s 6 microsec integration time on PSI5 60 post-trigger samples PSI5 10 microsec integration time on PSI4 2 post-trigger samples PSI4 Both cameras triggered. PSI4 is setup to view B-side with F/16 aperture and an ND 1.0 filter in the view. The filter is D_alpha. |
| Jun 29 2005 10:45:57:437AM | 1050628002 | Jim Terry | H-mode at 1.015 s, 1st small ELM at 1.094 s
Setup to puff NINJA (A-B limiter) with 563 torr D2 at 0.58 s for 0.2 s Should hit the plasma at 0.68 sec. 6810 digitization freq is to 500 kHz triggering at 0.7 s Setup to trigger the PSI5 and PSI4 with the ELM trigger (0.5 v ref). ELM trigger gate is 0.705 to 1.2 s Hard trigger at 1.19 s (PSI5) and 1.7 s (PSI4) 6 microsec integration time on PSI5 60 post-trigger samples PSI5 10 microsec integration time on PSI4 2 post-trigger samples PSI4 Probably triggered on hard triggers. NINJA puff OK - only d7 (view 40) is saturated. PSI4 images are black. |
| Jun 29 2005 11:06:13:957AM | 1050628003 | Jim Terry | Remove ramp on RF, go to 3 MW step
Actual is intermittant at 1 MW H-mode at 0.75 s, small ELMs ELM later J Hughes reports 1 keV pedestal temperature NINJA puff (A-B limiter) with 563 torr D2 at 0.58 s for 0.2 s Should hit the plasma at 0.68 sec. 6810 digitization freq is to 500 kHz triggering at 0.7 s Setup to trigger the PSI5 and PSI4 with the ELM trigger (threshold 0.3) ELM trigger gate is 0.705 to 1.2 s Hard trigger at 0.95 s (PSI5 and PSI4) 6 microsec integration time on PSI5 60 post-trigger samples PSI5 10 microsec integration time on PSI4 2 post-trigger samples PSI4 triggered on dithers See nothing on PSI4????? NINJA puff OK - only d7 (view 40) is saturated. |
| Jun 29 2005 11:07:37:393AM | 1050628004 | Jim Terry | Remove ramp on RF, go to 3 MW step
Actual is intermittant at 1 MW H-mode at 0.75 s, small ELMs ELM later J Hughes reports 1 keV pedestal temperature NINJA puff (A-B limiter) with 563 torr D2 at 0.58 s for 0.2 s Should hit the plasma at 0.68 sec. 6810 digitization freq is to 500 kHz triggering at 0.7 s Setup to trigger the PSI5 and PSI4 with the ELM trigger (threshold 0.3) ELM trigger gate is 0.705 to 1.2 s Hard trigger at 0.95 s (PSI5) and 0.95 s (PSI5) 4 microsec integration time on PSI5 60 post-trigger samples PSI5 10 microsec integration time on PSI4 2 post-trigger samples PSI4 triggered on ELM at 0.827 s - good See nothing on PSI4????? NINJA puff OK - only d7 (view 40) is saturated. |
| Jun 29 2005 11:20:23:707AM | 1050628004 | Jim Terry | Actual RF is intermittant to 3 MW
H-mode at 0.72 s, small ELMs later NINJA puff (A-B limiter) with 563 torr D2 at 0.58 s for 0.2 s Should hit the plasma at 0.68 sec. 6810 digitization freq is to 500 kHz triggering at 0.7 s Setup to trigger the PSI5 and PSI4 with the ELM trigger (threshold 0.3) ELM trigger gate is 0.705 to 1.2 s Hard trigger at 0.95 s (PSI5) and 0.95 s (PSI4) 4 microsec integration time on PSI5 60 post-trigger samples PSI5 10 microsec integration time on PSI4 2 post-trigger samples PSI4 triggered on ELM at 0.827 s - good See nothing on PSI4????? NINJA puff OK - only d7 (view 40) is saturated. |
| Jun 29 2005 11:26:17:770AM | 1050628005 | Jim Terry | Actual RF is intermittant with 3 MW max
H-modes, but no clear ELMs NINJA puff (A-B limiter) with 563 torr D2 at 0.58 s for 0.2 s Should hit the plasma at 0.68 sec. 6810 digitization freq is to 500 kHz triggering at 0.7 s Setup to trigger the PSI5 and PSI4 with the ELM trigger (threshold 0.3) ELM trigger gate is 0.705 to 1.2 s Hard trigger at 0.95s (PSI5 & PSI4) 4 microsec integration time (PSI5) 60 post-trigger samples PSI5 10 microsec integration time (PSI4) 2 post-trigger samples PSI4 Neither camera triggered |
| Jun 29 2005 11:33:22:877AM | 1050628007 | Jim Terry | Actual RF is intermittant with 3 MW max
H-modes, but no clear ELMs NINJA puff (A-B limiter) with 563 torr D2 at 0.58 s for 0.2 s Should hit the plasma at 0.68 sec. 6810 digitization freq is to 500 kHz triggering at 0.7 s Setup to trigger the PSI5 and PSI4 with the ELM trigger (threshold 0.3) ELM trigger gate is 0.705 to 1.2 s Hard trigger at 0.95s (PSI5 & PSI4) 4 microsec integration time (PSI5) 60 post-trigger samples (PSI5) 10 microsec integration time (PSI4) 2 post-trigger samples PSI4 PSI5 triggered at 0.85s, but not on ELM (probably a back transition) No PSI4 images |
| Jun 28 2005 12:09:09:763PM | 1050628008 | Jim Terry | Actual RF is 3 MW max
H-modes, but no clear ELMs NINJA puff (A-B limiter) with 563 torr D2 at 0.58 s for 0.2 s Should hit the plasma at 0.68 sec. 6810 digitization freq is to 500 kHz triggering at 0.7 s Setup to trigger the PSI5 and PSI4 with the ELM trigger (threshold 0.3) ELM trigger gate is 0.705 to 1.2 s Hard trigger at 0.95s (PSI5 & PSI4) 6 microsec integration time (PSI5) 60 post-trigger samples (PSI5) 30 msec integration time (PSI4) !!!! 2 post-trigger samples PSI4 PSI5 triggered at 0.783 s, but not on ELM (appears to be noise) PSI4 imges are black even though 30 ms frame time ?? |
| Jun 29 2005 11:46:53:770AM | 1050628010 | Jim Terry | Actual RF is good, ramped from 1 to 3 MW max
H-modes, but no good ELMs (Type 3 or dithers NINJA puff (A-B limiter) with 563 torr D2 at 0.58 s for 0.2 s Should hit the plasma at 0.68 sec. 6810 digitization freq is to 500 kHz triggering at 0.7 s Setup to trigger the PSI5 and PSI4 with the ELM trigger (threshold 0.3) ELM trigger gate is 0.705 to 1.2 s Hard trigger at 0.95s (PSI5 & PSI4) 6 microsec integration time (PSI5) 60 post-trigger samples PSI5 30 msec integration time (PSI4) 2 post-trigger samples PSI4 PSI5 triggered at 0.75 s, but not on ELM PSI4 images @ 30msec/frame!!!! Clear effect of L to H transition on fast-diodes |
| Jun 29 2005 12:06:02:077PM | 1050628012 | Jim Terry | Actual RF is good, ramped from 1 to 3 MW max
H-modes, but no good ELMs (long duration ELMS or dithers) NINJA puff (A-B limiter) with 563 torr D2 at 0.58 s for 0.2 s Should hit the plasma at 0.68 sec. 6810 digitization freq is to 500 kHz triggering at 0.7 s Setup to trigger the PSI5 and PSI4 with the ELM trigger (threshold 0.3) ELM trigger gate is 0.705 to 1.2 s Hard trigger at 0.95s (PSI5 & PSI4) 6 microsec integration time (PSI5) 60 post-trigger samples PSI5 30 msec integration time (PSI4) !!!! 2 post-trigger samples PSI4 PSI5 triggered at 0.906 s, but on ELM or dither |
| Jun 28 2005 12:55:29:560PM | 1050628013 | Jim Terry | Removed the ND 1.0 filter from the PSI4 view and increased the aperture from
F/16 to F/5.6. More limited on inner nose. Actual RF is good, ramped from 1 to 3 MW max H-modes, but no good ELMs (Type 3 or dithers) NINJA puff (A-B limiter) with 563 torr D2 at 0.58 s for 0.2 s Should hit the plasma at 0.68 sec. 6810 digitization freq is to 500 kHz triggering at 0.7 s Setup to trigger the PSI5 and PSI4 with the ELM trigger (threshold 0.3) ELM trigger gate is 0.905 to 1.2 s Hard trigger at 0.95s (PSI5 & PSI4) 6 microsec integration time (PSI5) 60 post-trigger samples PSI5 1 msec integration time (PSI4) 4 post-trigger samples PSI4 PSI5 triggered at 0.95 s, but not on ELM saturated PSI4 images @ 1msec/frame |
| Apr 6 2006 11:28:41:133AM | 1050628014 | Jim Terry | Going to JFT2M shape (load shot 1050623033) since
we are not getting the ELMs we want. PSI4 view is F/5.6 with no ND filter. Actual RF is good, ramped from 1 to 3 MW max H-modes, good Type I ELMs much better than with limited shape. NINJA puff (A-B limiter) with 563 torr D2 at 0.58 s for 0.2 s Should hit the plasma at 0.68 sec. 6810 digitization freq is to 500 kHz triggering at 0.7 s Setup to trigger the PSI5 and PSI4 with the ELM trigger (threshold 0.3) ELM trigger gate is 0.705 to 1.005 s Hard trigger at 0.95s (PSI5 & PSI4) 6 microsec integration time (PSI5) 60 post-trigger samples PSI5 4 microsec integration time (PSI4) 4 post-trigger samples PSI4 PSI5 and PSI4 triggered on the oscillation (but not an ELM) at 0.727 s PSI4 signal could be brighter Great fast-diode data coherent precursor oscillations on inboard views (e.g. at 0.9284 and 0.955 s) |
| Jun 28 2005 01:24:57:077PM | 1050628015 | Jim Terry | JFT2M shape
PSI4 view is F/5.6 with no ND filter. Actual RF is good, ramped from 1 to 3 MW max H-modes, good Type I ELMs NINJA puff (A-B limiter) with 563 torr D2 at 0.58 s for 0.2 s Should hit the plasma at 0.68 sec. 6810 digitization freq is to 500 kHz triggering at 0.7 s Setup to trigger the PSI5 and PSI4 with the ELM trigger (threshold 0.3) ELM trigger gate is 0.705 to 1.005 s Hard trigger at 0.95s (PSI5 & PSI4) 6 microsec integration time (PSI5) 60 post-trigger samples PSI5 10 microsec integration time (PSI4) 4 post-trigger samples PSI4 PSI5 did not trigger PSI4 triggered on the 1st ELM at 0.95 s PSI4 signal could be brighter |
| Apr 6 2006 11:43:27:680AM | 1050628016 | Jim Terry | JFT2M shape
PSI4 view is F/5.6 with no ND filter. Actual RF is good, ramped from 1 to 3 MW max H-modes, good Type I ELMs much better than with limited shape. NINJA puff (A-B limiter) with 563 torr D2 at 0.78 s for 0.2 s Should hit the plasma at 0.88 sec. 6810 digitization freq is to 500 kHz triggering at 0.9 s Setup to trigger the PSI5 and PSI4 with the ELM trigger (threshold 0.5) ELM trigger gate is 0.905 to 1.205 s Hard trigger at 1.15s (PSI5 & PSI4) 6 microsec integration time (PSI5) 60 post-trigger samples PSI5 10 microsec integration time (PSI4) 4 post-trigger samples PSI4 NOTE that the strobes show up only for the post trigger samples! PSI5 and PSI4 triggered on the 1st ELM at 0.997 s - movie is OK, not great Great - see change in the PSI4 images great data on fast-diodes see coherent precursor see 1.012 s. |
| Apr 6 2006 11:48:32:993AM | 1050628017 | Jim Terry | JFT2M shape
PSI4 view has aperture enlarged to F/4 with no ND filter. Actual RF is good, ramped from 1 to 3 MW max no H-modes - probably density is below the threshold. NINJA puff (A-B limiter) with 563 torr D2 at 0.78 s for 0.2 s Should hit the plasma at 0.88 sec. 6810 digitization freq is to 500 kHz triggering at 0.7 s Setup to trigger the PSI5 and PSI4 with the ELM trigger (threshold 0.5) ELM trigger gate is 0.905 to 1.205 s Hard trigger at 1.15s (PSI5 & PSI4) 6 microsec integration time (PSI5) 60 post-trigger samples PSI5 10 microsec integration time (PSI4) 4 post-trigger samples PSI4 PSI5 and PSI4 triggered at 0.905 s, not on an ELM. PSI movie is poor. |
| Apr 6 2006 11:49:15:540AM | 1050628018 | Jim Terry | JFT2M shape
PSI4 view has aperture enlarged to F/4 with no ND filter. Actual RF is good, ramped from 1 to 3 MW max H-modes with good ELMs NINJA puff (A-B limiter) with 563 torr D2 at 0.78 s for 0.2 s Should hit the plasma at 0.88 sec. 6810 digitization freq is to 500 kHz triggering at 0.7 s Setup to trigger the PSI5 and PSI4 with the ELM trigger (threshold 0.5) ELM trigger gate is 0.905 to 1.205 s Hard trigger at 1.15s (PSI5 & PSI4) 6 microsec integration time (PSI5) 60 post-trigger samples PSI5 10 microsec integration time (PSI4) 4 post-trigger samples PSI4 PSI5 and PSI4 triggered at 0.9125 s on second of a pair of ELMs. PSI5 movie is poor. Clear change in PSI4 images Clear ELM propagation on diodes - complex structure in single ELM |
| Apr 6 2006 11:56:53:290AM | 1050628019 | Jim Terry | JFT2M shape
PSI4 view has aperture enlarged to F/4 with no ND filter. Actual RF is good, ramped from 1 to 3 MW max H-modes with good ELMs NINJA puff (A-B limiter) with 563 torr D2 at 0.78 s for 0.2 s Should hit the plasma at 0.88 sec. 6810 digitization freq is to 500 kHz triggering at 0.7 s Setup to trigger the PSI5 and PSI4 with the ELM trigger (threshold 0.5) ELM trigger gate is 0.905 to 1.205 s Hard trigger at 1.15s (PSI5 & PSI4) 6 microsec integration time (PSI5) 60 post-trigger samples PSI5 10 microsec integration time (PSI4) 4 post-trigger samples PSI4 PSI5 and PSI4 triggered at 1.07 s a single ELM. PSI5 movie is the best yet - start of ELM effect is frame 229 Clear change in PSI4 images -very good - should see something from ELM around frame 18. Too late for most of the diodes - complex structure in single ELM |
| Jun 28 2005 02:58:39:810PM | 1050628021 | Jim Terry | JFT2M shape
PSI4 view has aperture enlarged to F/4 with no ND filter. Actual RF is good, ramped from 1 to 3 MW max H-modes with good ELMs NINJA puff (A-B limiter) upped to 603 torr D2 at 0.78 s for 0.2 s Should hit the plasma at 0.88 sec. 6810 digitization freq is to 500 kHz triggering at 0.7 s Setup to trigger the PSI5 and PSI4 with the ELM trigger (threshold 0.5) ELM trigger gate is 0.905 to 1.205 s Hard trigger at 1.15s (PSI5 & PSI4) 6 microsec integration time (PSI5) 60 post-trigger samples PSI5 4 microsec integration time (PSI4) 4 post-trigger samples PSI4 PSI5 and PSI4 triggered at 0.938 s a single ELM - very good Clear change in PSI4 images -very good Very good on the diodes - complex sturcture in single ELM |
| Jun 29 2005 01:12:08:450PM | 1050628022 | Jim Terry | JFT2M shape
PSI4 view has aperture enlarged to F/4 with no ND filter. Actual RF is good, ramped from 1 to 3 MW max H-modes with good ELMs NINJA puff (A-B limiter) upped to 603 torr D2 at 0.78 s for 0.2 s Should hit the plasma at 0.88 sec. 6810 digitization freq is to 500 kHz triggering at 0.7 s Setup to trigger the PSI5 and PSI4 with the ELM trigger (threshold 0.5) ELM trigger gate is 0.905 to 1.205 s Hard trigger at 1.15s (PSI5 & PSI4) 6 microsec integration time (PSI5) 60 post-trigger samples PSI5 2 microsec integration time (PSI4)(isn't resolved on digitizer) 8 post-trigger samples PSI4 PSI5 and PSI4 triggered at 0.908 s a single ELM - very good Clear change in PSI4 images -very good Very good on the diodes - complex structure in single ELM |
| Jun 28 2005 03:30:52:903PM | 1050628023 | Jim Terry | JFT2M shape
PSI4 view has aperture enlarged to F/4 with no ND filter. Increase outer gap to 2.0 cm - saw outer gap change Actual RF is good, ramped from 1 to 3 MW max H-modes with good ELMs NINJA puff (A-B limiter) upped to 603 torr D2 at 0.78 s for 0.2 s Should hit the plasma at 0.88 sec. 6810 digitization freq is upped to 1000 kHz triggering at 0.904 s Setup to trigger the PSI5 and PSI4 with the ELM trigger (threshold 0.5) ELM trigger gate is 0.905 to 1.205 s Hard trigger at 1.15s (PSI5 & PSI4) 6 microsec integration time (PSI5) 156 post-trigger samples PSI5 2 microsec integration time (PSI4) 18 post-trigger samples PSI4 PSI5 and PSI4 triggered at 0.918 s a single ELM - very good Clear change in PSI4 images - very good Very good on the diodes - complex sturcture in single ELM |
| Jun 28 2005 03:47:27:467PM | 1050628024 | Jim Terry | JFT2M shape
PSI4 view has aperture enlarged to F/4 with no ND filter. outer gap at 1.8 cm Actual RF is good, ramped from 1 to 3 MW max H-modes with good ELMs NINJA puff (A-B limiter) upped to 603 torr D2 at 0.78 s for 0.2 s Should hit the plasma at 0.88 sec. 6810 digitization freq is upped to 1000 kHz triggering at 0.904 s Setup to trigger the PSI5 and PSI4 with the ELM trigger (threshold 0.5) ELM trigger gate is 0.905 to 1.205 s Hard trigger at 1.15s (PSI5 & PSI4) 6 microsec integration time (PSI5) 156 post-trigger samples PSI5 4 microsec integration time (PSI4) 20 post-trigger samples PSI4 PSI5 and PSI4 triggered at 0.925 s a single ELM - very good Clear change in PSI4 images - very good Very good on the diodes - complex sturcture in single ELM duration of ELM effect on diodes is ~210 microsec with trigger about 130 microsec after start. This means to see to entire ELM with 28 frames, I should put the frame exposure to 8 microsec and use 11 post trigger frames. |
| Jun 28 2005 03:57:58:183PM | 1050628025 | Jim Terry | moved X-pt out in R by 2 cm
This made a big change in the ELMs which are now longer and are not sharp spikes, but are flat on top. PSI4 view has aperture enlarged to F/4 with no ND filter. outer gap at 1.8 cm Actual RF is good, ramped from 1 to 3 MW max H-modes with good ELMs NINJA puff (A-B limiter) upped to 603 torr D2 at 0.78 s for 0.2 s Should hit the plasma at 0.88 sec. 6810 digitization freq is 1000 kHz triggering at 0.904 s Setup to trigger the PSI5 and PSI4 with the ELM trigger (threshold 0.5) ELM trigger gate is 0.905 to 1.205 s Hard trigger at 1.15s (PSI5 & PSI4) 6 microsec integration time (PSI5) 156 post-trigger samples PSI5 4 microsec integration time (PSI4) 20 post-trigger samples PSI4 PSI5 and PSI4 triggered at 0.920 s a single ELM - very good PSI4 is saturated Very good on the diodes - complex sturcture in single ELM duration of ELM effect on diodes is ~5000 microsec |
| Jun 28 2005 04:27:21:623PM | 1050628026 | Jim Terry | moved X-pt out in R by another 2 cm
This made an additional change in the "ELMs" which now should probably be called back transitions PSI4 view has aperture enlarged to F/4 with no ND filter. outer gap at 1.8 cm Actual RF is good, ramped from 1 to 3 MW max H-modes with good ELMs NINJA puff (A-B limiter) upped to 603 torr D2 at 0.78 s for 0.2 s Should hit the plasma at 0.88 sec. 6810 digitization freq is 1000 kHz triggering at 0.904 s Setup to trigger the PSI5 and PSI4 with the ELM trigger (threshold 0.5) ELM trigger gate is 0.905 to 1.205 s Hard trigger at 1.15s (PSI5 & PSI4) 6 microsec integration time (PSI5) 156 post-trigger samples PSI5 4 microsec integration time (PSI4) 20 post-trigger samples PSI4 PSI5 and PSI4 triggered at 0.913 s a single event - good, but I probably just missed the back transition PSI4 is probably a little saturated Very good on the diodes - complex sturcture in single "dither" duration of "dither" effect on diodes is >5000 microsec |
| Jun 29 2005 01:45:56:920PM | 1050628027 | Jim Terry | moved X-pt back in to -0.5 cm inside of where we were on shot 024
ELMs reappeared, but are od less distinct quality than 024 and before. PSI4 view has aperture enlarged to F/4 with no ND filter. outer gap at 1.8 cm Actual RF is good, ramped from 1 to 3 MW max H-modes with good ELMs NINJA puff (A-B limiter) at 686 torr D2 at 0.78 s for 0.2 s Should hit the plasma at 0.88 sec. 6810 digitization freq is 1000 kHz triggering at 0.904 s Setup to trigger the PSI5 and PSI4 with the ELM trigger (threshold 0.5) ELM trigger gate is 0.905 to 1.205 s Hard trigger at 1.15s (PSI5 & PSI4) 4 microsec integration time (PSI5) !!! 156 post-trigger samples PSI5 2 microsec integration time (PSI4) 20 post-trigger samples PSI4 PSI5 and PSI4 triggered at 0.909 s on a single ELM Good images and diode data |
| Jun 29 2005 01:45:38:357PM | 1050628028 | Jim Terry | X-pt back to where we were on shot 024
PSI4 view has aperture enlarged to F/4 with no ND filter. outer gap at 1.8 cm Actual RF is good, ramped from 1 to 3 MW max H-modes with good ELMs NINJA puff (A-B limiter) at 686 torr D2 at 0.78 s for 0.2 s Should hit the plasma at 0.88 sec. 6810 digitization freq is 1000 kHz triggering at 0.904 s Setup to trigger the PSI5 and PSI4 with the ELM trigger (threshold 0.5) ELM trigger gate is 0.905 to 1.205 s Hard trigger at 1.15s (PSI5 & PSI4) 4 microsec integration time (PSI5) !!! 156 post-trigger samples PSI5 2 microsec integration time (PSI4) 20 post-trigger samples PSI4 PSI5 and PSI4 triggered at 0.905 s during multiple ELMs Images and diode data show no distinct ELM |
| Jun 28 2005 05:00:54:280PM | 1050628029 | Jim Terry | X-pt back to where we were on shot 024
Move RF waveform later by 0.1 s, since ELMs are better early in the pulse PSI4 view has aperture enlarged to F/4 with no ND filter. outer gap at 1.8 cm Actual RF is good, ramped from 1 to 3 MW max H-modes with good ELMs NINJA puff (A-B limiter) at 686 torr D2 at 0.78 s for 0.2 s Should hit the plasma at 0.88 sec. 6810 digitization freq is 1000 kHz triggering at 0.904 s Setup to trigger the PSI5 and PSI4 with the ELM trigger (threshold 0.5) ELM trigger gate is 0.905 to 1.205 s Hard trigger at 1.15s (PSI5 & PSI4) 4 microsec integration time (PSI5) !!! 156 post-trigger samples PSI5 2 microsec integration time (PSI4) 16 post-trigger samples PSI4 PSI5 and PSI4 triggered at 0.929 s during single ELM Images and diode data OK looks like the ELMs are degrading |
| Jun 29 2005 01:49:45:077PM | 1050628030 | Jim Terry | X-pt back to where we were on shot 024
Make RF waveform Step to 3 MW instead of ramp PSI4 view has aperture enlarged to F/4 with no ND filter. outer gap at 1.8 cm Actual RF is good H-modes with good ELMs NINJA puff (A-B limiter) at 686 torr D2 at 0.78 s for 0.2 s Should hit the plasma at 0.88 sec. 6810 digitization freq is 1000 kHz triggering at 0.904 s Setup to trigger the PSI5 and PSI4 with the ELM trigger (threshold 0.5) ELM trigger gate is 0.905 to 1.205 s Hard trigger at 1.15s (PSI5 & PSI4) 6 microsec integration time (PSI5) !!! 156 post-trigger samples PSI5 2 microsec integration time (PSI4) 4 post-trigger samples PSI4 PSI5 and PSI4 triggered at 0.914 s triggered, but not on ELM Images and diode data OK, but not ELM diagnostic |
| Jun 28 2005 05:36:41:840PM | 1050628031 | Jim Terry | Try to elongate the plasma, keeping the lower X-pt fixed.
Go back to a ramped RF waveform 1 to 3 MW Actual RF is good, but elongation didn't change much, certainly not in the way we wanted. PSI4 view has aperture enlarged to F/4 with no ND filter. outer gap at 1.8 cm H-modes with some odd ELMs NINJA puff (A-B limiter) at 686 torr D2 at 0.78 s for 0.2 s Should hit the plasma at 0.88 sec. 6810 digitization freq is 1000 kHz triggering at 0.904 s Setup to trigger the PSI5 and PSI4 with the ELM trigger (threshold 0.5) ELM trigger gate is 0.905 to 1.205 s Hard trigger at 1.15s (PSI5 & PSI4) 6 microsec integration time (PSI5) !!! 156 post-trigger samples PSI5 2 microsec integration time (PSI4) 4 post-trigger samples PSI4 PSI5 triggered at 0.923 s triggered on the second of an ELM pair PSI4 didn't trigger PSI5 Images and diode data OK |
| Physics Operator Comments | |||
| Jun 28 2005 09:09:20:967AM | Robert Granetz | GPC2 is not working, GPC is. There is some question though about which B-field the GPC is set up for, since the last shot from last week was at 6 T, and Amanda is away at the EPS meeting today. Frank Shefton is pumping out GPC2 and may be able to do a helium fill and get it back online. | |
| Jun 28 2005 09:28:54:857AM | 1050628001 | Robert Granetz | Plasma. High current disruption. My mistake. I copied the baseline shot from last Friday and substituted the desired segment 2. But last Friday we were running with segment 3, and this was still the active one after I loaded segment 2. Next shot: turn off seg 3, turn on seg 2. Also increase pre-fill pulse to 20 ms. |
| Jun 28 2005 09:47:16:230AM | 1050628002 | Robert Granetz | Plasma. Good shot. This is what the session leader wanted. The equilibrium is very close to limiting on the inboard nose, but actually remains just barely diverted. All discharge parameters are as desired. Prf = 1 -> 2+ MW. Next shot: move RXL in by 0.5 cm. More RF power. |
| Jun 28 2005 10:02:39:873AM | 1050628003 | Robert Granetz | Plasma. Good shot. Still remains just barely diverted. J-port RF didn't stay on. Next shot: repeat to get the RF. |
| Jun 28 2005 10:20:54:340AM | 1050628004 | Robert Granetz | Plasma. Good shot. A few EFIT reconstructions are limited on the inboard nose, but most remain diverted, so it's really close. Prf=2+ MW, and flat. (JT asked them to remove the ramp.) Next shot: repeat, no PCS changes |
| Jun 28 2005 10:44:25:623AM | 1050628005 | Robert Granetz | Plasma. Good shot. Prf=2-3 MW. I still don't see any Type-I ELM's. Cell access after this shot in order to work on the trigger for the LASL IR camera. Next shot: no PCS changes |
| Jun 28 2005 10:55:54:513AM | 1050628006 | Robert Granetz | Dud. Next shot: add 2 ms to pre-fill pulse and increase Bz by adding 10 amps to IC_EF4U. |
| Jun 28 2005 11:18:18:997AM | 1050628007 | Robert Granetz | Plasma. Good shot. Prf=3 MW. No big ELMs by my eye. Next shot: move RXL back out by 0.5 cm (same as at beginning of the run). |
| Jun 28 2005 11:32:28:950AM | 1050628008 | Robert Granetz | Plasma. Good shot. Prf=3 MW. RXL moved out, as requested. Some spikes on the H-alpha may be big ELMs. Nope, JT says they aren't big ELMs. Next shot: lower the RF power. Also tweak Bz0. |
| Jun 28 2005 11:45:41:560AM | 1050628009 | Robert Granetz | Plasma. Disrupted very early. Looks like a big impurity injection. Next shot: try again, no PCS changes. |
| Jun 28 2005 11:58:28:873AM | 1050628010 | Robert Granetz | Plasma. Good shot. Prf linearly ramps from 1 to 3 MW cleanly. Small ELMs. Next shot: Move RXL in by 1 cm to solidly limit on the inboard nose. |
| Jun 28 2005 12:03:34:310PM | 1050628011 | Robert Granetz | Dud. Next shot: increase pre-fill another 2 ms. |
| Jun 28 2005 12:45:29:840PM | 1050628012 | Robert Granetz | Plasma. Good shot. Nice RF power ramp again, 1 -> 3 MW. Quoting JT, "These are not Type I ELMs". Cell access after this shot. Next shot: Reduce RXL another 1 cm to limit harder. (This required changing the estimator factor and the controller time constant.) |
| Jun 28 2005 01:14:20:730PM | 1050628013 | Robert Granetz | Plasma. Good shot. Hard-limited on inboard nose, but no big ELMs. There was a very bright hot spot on the girdle at F-port (wide2 view). This probably led to the disruption at t=0.92 s. Next shot: switch gears and load in the recent JFT-2M equilibrium from 1050623033. Keep the RF ramp. |
| Jun 28 2005 01:08:29:840PM | 1050628014 | Robert Granetz | Plasma. Good shot. JFT-2M shape. Prf ramps 1 -> 3 MW. JT: "Those are real ELMs". This was the nicest startup today by far. Next shot: no PCS changes |
| Jun 28 2005 01:17:21:433PM | 1050628015 | Robert Granetz | Plasma. Good shot. JFT-2M shape. ELMs (but not large ones). Prf ramped 1 -> 3 MW. This startup went back to the crappy ones we've been having all day long (with the exception of shot 14). Next shot: enable argon puff, set it at 50 ms. |
| Jun 28 2005 01:55:43:810PM | 1050628016 | Robert Granetz | Plasma. Good shot. Some ELMs. Nice RF ramp 1 -> 3 MW. Good startup except for the late breakdown. Cell access. Next shot: no PCS changes. |
| Jun 28 2005 02:03:50:310PM | 1050628017 | Robert Granetz | Plasma. Good shot. Disrupted in rampdown. Prf ramp, 1 -> 3 MW, but no H-modes. Are we below the low-density threshold limit? Next shot: raise nl_04 to 0.5e20 m-2 (from 0.35) |
| Jun 28 2005 02:19:22:340PM | 1050628018 | Robert Granetz | Plasma. Good shot. Prf ramp, 1 -> 3 MW. Lots of (small) ELMs. Nice startup. Next shot: decrease density slightly to nl_04=0.45e20 m-2 (from 0.5) |
| Jun 28 2005 02:34:40:857PM | 1050628019 | Robert Granetz | Plasma. Good shot. Prf ramp, 1 -> 3 MW. Some ELMs. Next shot: no PCS changes |
| Jun 28 2005 02:37:31:293PM | 1050628020 | Robert Granetz | Dud. Next shot: increase pre-fill by 2 more ms. |
| Jun 28 2005 04:04:54:513PM | 1050628021 | Robert Granetz | Plasma. Good shot. Lots of ELMs. Prf ramp 1 -> 3 MW. Startup bashed into something. Next shot: no PCS changes. |
| Jun 28 2005 03:12:19:497PM | 1050628022 | Robert Granetz | Plasma. Good shot. Lots of small ELMs. RF ramp 1 -> 3 MW. Next shot: increase outer gap from 15 mm to 20 mm by moving RCUR in by 2.5 mm. |
| Jun 28 2005 03:29:59:497PM | 1050628023 | Robert Granetz | Plasma. Good shot. Prf ramp 1 -> 3 MW. Next shot: at Ian's request (he's looking at RCUR control) increase RCUR derivative gain to 10 (full scale) after t=1.0 s. |
| Jun 28 2005 03:37:25:560PM | 1050628024 | Robert Granetz | Plasma. Good shot. Prf ramp, 1 -> 3 MW. Lots of small ELMs. Next shot: move RXL out by 2 cm. Also increase pre-fill by 1 ms. |
| Jun 28 2005 03:52:39:577PM | 1050628025 | Robert Granetz | Plasma. Good shot. RXL moved out, as requested. ELM character changed dramatically. Outer leg still goes to the floor, just missing the outboard diverter vertical face. Next shot: move RXL out another 2 cm. Will the ELMs/dithers go away completely? |
| Jun 28 2005 04:07:02:543PM | 1050628026 | Robert Granetz | Plasma. Good shot. Lots of large H/L back transitions. Prf ramp, 1 -> 3 MW. The outer leg is now striking the outboard divertor vertical face. Next shot: put RXL 0.5 cm inside of where we started from (i.e. 4.5 cm inside of where we are now). |
| Jun 28 2005 04:20:09:530PM | 1050628027 | Robert Granetz | Plasma. Good shot. RXL moved in, DOUTL=0.80. Prf ramp, 1 -> 3 MW. Small ELMs. Next shot: move RXL out by 0.5 cm. |
| Jun 28 2005 04:33:50:717PM | 1050628028 | Robert Granetz | Plasma. Good shot. ELMy. Prf ramp 1 -> 3 MW. Next shot: no PCS changes. Move RF later by 100 ms. |
| Jun 28 2005 04:46:51:730PM | 1050628029 | Robert Granetz | Plasma. Good shot. Prf ramp 1 -> 3 MW, delayed by 100 ms compared to all preceding shots today. ELMy. Next shot: no PCS changes. Program RF for 3 MW flattop instead of a ramp. |
| Jun 28 2005 04:59:59:737PM | 1050628030 | Robert Granetz | Plasma. Good shot. RF flattop wasn't too good. Neither were the ELMs. Next shot: decrease ZXU by 5 cm to increase upper elongation. Go back to an RF ramp. |
| Jun 28 2005 05:09:42:577PM | 1050628031 | Robert Granetz | Plasma. Good shot. Upper elongation didn't change much, if at all. Prf ramp 1 -> 3 MW. Somewhat ELMy. End of run. Boronization tonight. |
| Engineering Operator Comments | ||||
| Shot | Time | Type | Status | Comment |
| 1 | 09:21:34:077AM | Plasma | Ok | |
| 2 | 09:34:36:310AM | Plasma | Ok | |
| 3 | 09:48:25:543AM | Plasma | Ok | |
| 4 | 10:03:29:560AM | Plasma | Ok | |
| 5 | 10:21:59:670AM | Plasma | Ok | |
| 6 | 10:48:58:700AM | Plasma | Ok | |
| 7 | 11:04:13:247AM | Plasma | Ok | |
| 8 | 11:18:39:577AM | Plasma | Ok | |
| 9 | 11:33:44:467AM | Plasma | Ok | |
| 10 | 11:46:37:170AM | Plasma | Ok | |
| 11 | 12:01:49:577PM | Plasma | Ok | |
| 12 | 12:14:30:903PM | Plasma | Ok | |
| 13 | 12:45:38:387PM | Plasma | Ok | |
| 14 | 12:59:06:107PM | Plasma | Ok | |
| 15 | 01:11:48:730PM | Plasma | Ok | |
| 16 | 01:25:31:027PM | Plasma | Ok | |
| 17 | 01:56:34:480PM | Plasma | Ok | |
| 18 | 02:09:17:010PM | Plasma | Ok | |
| 19 | 02:21:47:137PM | Plasma | Ok | |
| 20 | 02:35:22:340PM | Plasma | Ok | |
| 21 | 02:48:06:387PM | Plasma | Ok | |
| 22 | 03:00:52:357PM | Plasma | Ok | |
| 23 | 03:17:03:717PM | Plasma | Ok | |
| 24 | 03:30:53:653PM | Plasma | Ok | |
| 25 | 03:43:28:997PM | Plasma | Ok | |
| 26 | 03:58:03:230PM | Plasma | Ok | |
| 27 | 04:11:51:263PM | Plasma | Ok | |
| 28 | 04:24:35:420PM | Plasma | Ok | |
| 29 | 04:38:21:623PM | Plasma | Ok | |
| 30 | 04:50:56:963PM | Plasma | Ok | |
| 31 | 05:03:46:920PM | Plasma | Ok | |