| Miniproposals | ||||||||||
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| Operators | |
| Session leader(s): | Joseph Snipes |
| Physics operator(s): | Steve Wolfe |
| Engineering operator(s): | Bill Parkin,Bill Byford,Gary Dekow |
| Engineering Operator Run Comment |
| MP#494 Fast Electron-Driven Alfven modes SL: Snipes PB: MP#537 Momentum |
| Session Leader Plans |
| Entered: Feb 26 2008 02:44:35:670PM |
| Author: Joseph Snipes |
| Session Leader Plan for 1080227 MP494a Fast Electron Driven Alfven Eigenmodes
The purpose of this run is to investigate the parametric dependences of the high frequency bursting modes observed in the very early current rise (0.02 - 0.035 s) of discharges with LHCD. In particular, we would like to check the dependence of the mode frequency on density and toroidal field to see if it scales as the Alfven velocity B/sqrt(n). If time permits, we will also check the dependence of the mode amplitude on input power, LH phasing, and if possible, on changes in magnetic shear and evolution of the q profile. We will start with a standard startup and this MP is only concerned with times before 0.1 s in segment 1, so another MP can piggyback on the rest of the pulse. Since it is difficult to do a controlled scan of density at these early times in the current rise, we will start with a toroidal field scan, beginning at 5.4 T and increase in several steps to the maximum allowed field, which is 6.3 T at the moment. We will take two or three shots at 5.4 T, 5.7 T, 6.0 T, 6.3 T, and 5.1 T (10 to 15 shots) and attempt to vary the density in the startup through changes in the prepuff. LHCD will be injected from 0 to 0.05 s starting at 0.4 MW with 90 degree current drive phasing. Then, we will choose which field gives the clearest high frequency modes and do a power scan 0.6 MW, 0.8 MW, 1.0 MW, 0.2 MW (4 shots). Then, we will return to the power level that gives the clearest modes and change the LH phase to 60 degrees and then change it to 120 degrees with two to three shots at each phase (4 to 6 shots). If time permits, we will then go to lower toroidal field and take two to three shots at 4.8 T, and 4.5 T (4 to 6 shots) at the phasing and power level with the clearest modes from the previous shots. If there is still time, we will try 4.2 T. All fast fluctuation diagnostics should be setup to look at the early current rise, particularly the first 0.05 s of the discharge with fast sampling to see modes with frequencies between 200 kHz and 1 MHz. |
| Physics Operators Plans |
| Entered: Feb 26 2008 03:23:38:830PM |
| Author: Steve Wolfe |
| PO_PLAN for Wednesday, Feb 27
MP#494 Fast Electron-Driven Alfven modes SL: Snipes PB: MP#537 Momentum impulse from rapid SSEP changes PB SL: Marr PO: wolfe ----------------- Engineering Setup ----------------- Run begins at 09:00 and ends at 17:00 Power systems as on: 1080226003 EXCEPT: TF current limit to 180kA. Acoil: +Dtop -Dbot -Jtop +Jbot (standard) Hybrid Enabled Gas setup: Fill B-Top with 6 psi D2 Hybrid enabled (PG4) fill B-side lower with 1 psi Ar Hybrid ENABLED (PG1) leave B-side upper as is Hybrid DISABLED (PG2) fill B-main (C-side) with 40 psi D2 Hybrid enabled (PG3) fill NINJA with 10 psi D2 DISABLED Enable gatevalves and shutters: ECE, VUV, Z-bolo Torvac gatevalve toggle (yes/no): NO Boronization(yes/no): no Overnight ECDC (yes/no): yes ICRF(yes/no): Not at start, perhaps later in the day LH(yes/no): yes, pulse starting at 0.02sec DNB(yes/no): NO Cryopump (yes/no): no Vessel temperature: 35/35/35 ------------------------------ ECDC Parameters (if requested) ------------------------------ gas and pressure: D2 at 2e-4 Torr sweep: 44/45/103 cm scan: 20/120 s ************************************************ Physop Plan: Since the primary experiment is only concerned with the early rampup, we will use the remainder of the discharge to do discharge development and perhaps get a head start on the piggyback MP on SSEP sweep. Start with a standard startup in segment 1, such as 1080226003 At some point we may want to change to a slow current ramp startup, as on 1080221007, which requires an early crowbar (.04sec) on OH's. This will also require an adjustment in segment 2 to avoid a big lurch at seg switch (which might need to be moved to .08). For seg2, use the highly modified near DN from simulation 1080225407, starting with the ZCUR sweep removed. The programmed ZCUR is -5mm, which should be close to DN. Following the SL_PLAN for MP#494a: 1) TF scan (in seg1) (10-15-shots) start at standard 5.4 T Raise to 5.7 (158kA), 6.0 (166.7kA), 6.3 T (175kA), then lower to 5.1T (141.7kA). Take 2-3 shots at each field, attempting to vary density by changing pre-puff and very early PG3. For this scan, LH from 0 to .05sec, 400kW, 90degree phasing. 2) LH Power scan (4 shots) : at field and puff with best AE modes, scan LH 0.6, 0.8, 1.0, 0.2MW 3) LH Phase scan (4-6 shots): at best power level scan phase 60 and 120 degrees 4) If time permits Drop TF in seg1 to 4.8, 4.6, 4.2T For Piggyback development, to be done as I have time: 1) Start with near DN discharge in seg2 and check SSEP; put CLEARIN refs on wires 10 and 11 (upper and lower zxa), SSEP ref program to zero on wire 12. Leave TF at 150kA in seg2. 2) Add back the zcur sweep, starting with 10msec from -.005 to +.006 (or other center point if indicated by SSEP. NINJA and Argon puff as desired. Put switch in CLEARIN reference zxa at time in between. Monitor gaps, EF2 response during sweep. Check overshoot on zcur, ssep. 3) Depending on results of 2, speed up or slow down sweep, vary endpoints. Use rotation diags (HIREX and/or CXRS and/or probes) to determine "sweet spot", rotation reversal. 4) If sweep is satisfactory, begin current and density scan as called for in MP#537 part II A-E. |
| Session Leader Summaries |
| Entered: Feb 27 2008 05:15:43:553PM |
| Author: Joseph Snipes |
| Overall it was a good run. There were 29 plasmas out of 35 attempts. We more or less completed scans of the toroidal field, LHCD power, and LHCD phasing and excited high frequency modes for most of these conditions. However, the results do not clearly show that these modes are indeed Alfvenic in that the frequency does not increase linearly with the toroidal field. The toroidal mode numbers of the modes need to be determined to see if changing mode numbers could be responsible for the observed changes in the frequency. The power scan did indicate that higher power generally gave higher mode amplitude, but there also seemed to be a change in mode frequency with changing input power, which was unexpected. One shot at 120 degree phasing with over 0.5 MW had no modes. Two shots with 60 degree phasing had some modes, though not as many as with 90 degree phasing. More analysis still needs to be done of the hard x ray data to determine how the fast electron energy changes with different conditions. Initial looks at both the PCI and reflectometer data showed no clearly coherent modes correlated with the high frequency magnetic perturbations. There were some indications of broadband incoherent modes that were approximately at the same time and frequency range as the magnetic perturbations on channel 32 of the PCI. The shots with clear high frequency modes include 1, 3, 4, 9, 11, 12, 13, 16, 17, 18, 20, 25, 27, 28, and 34. Further analysis is required to make sense of the data.
|
| Physics Operator Summaries |
| Entered: Feb 27 2008 05:54:30:457PM |
| Author: Steve Wolfe |
Physop summary for Wednesday, Feb 27, 2008
MP: 494A Fast Electron-Driven Alfven modes
Piggyback MP#537 Momentum impulse from rapid SSEP changes
Lurker: 481A Li pellet imaging
SL: Snipes
Piggyback SL's: K Marr, J. Rice, A Ince-Cushman
We accomplished almost all the points in the SL_PLAN, although
the observed frequency of the modes did not seem to scale as
expected. Joe needs to do some further analysis, particularly
of n number, to unravel this. The plasma parameters during the
early startup proved very difficult to control. Lots of fiddling
with pg4 levels and OH voltages to try to affect the current rise
rate and the density before 25msec mostly did not have predictable
effects, although these parameters did change on their own, giving
some range for analysis. Startups at BT between 4.8 and 6.3T were
obtained; for the low field point I changed the EF1 currents by
100A, not sure if it was actually needed or helpful. Most of the
startups were actually run at 5.1T, which had given the best modes
in the field scan. For the high field case, we needed to start
the TF pulse at -1.2sec instead of the usual -1.0sec.
The piggyback development of zcur sweeps for ssep variation was
pretty successful. The HIREX_Sr guys were seeing clear changes
in the core velocity, with time constants much longer than the
typical 10msec sweep I was running. This effect seemed to be somewhat
sensitive to a density increase that accompanied the transition to
upper null. The upper null phase of all these cases had substantial
marfes, even after the target density was lowered from .8 to .7 at
shot#20. We spent most of the day running a zcur variation of 16mm
in 10msec. From shot#25 on we also did a reverse sweep of half that size
starting at 1.1sec; these were also 10msec duration until shot#34, which
was 5msec. Ken also saw velocity changes, and will need to do some
more analysis to decide on the required sweep rate and magnitude
for his experiment. No scans of current or density were performed,
beyond the one reduction in nl04 from 8 to 7e19.
I spent some time playing with the timing and reference for the clearin
observer in the upper null configuration, but did not get anything that
obviously improved the thrash in the inner and outer gaps during
the transitions. If it turns out to be critical, this will need more
work.
I tried to symmetrize the x-points as requested by Brian, setting the
RXU to zero on shots#29 and 30, but both disrupted. #29 seemed to
have a problem at crossover, but 30 went verticaly unstable after
the sweep to upper null. This configuration will need further development.
Brock got permission to fire pellets from shot#23 on, at 1.4sec,
and got a good fraction in. Some led to disruptions early in rampdown,
some didn't.
The last shot (#35) was a locked mode shot from 1080215001 (seg3),
for HIREX calibration. This was sort of successful, but was only
locked from .75 to 1.0sec, judging from the ece.
Scorecard:
-----------
No power shots 1
Duds 1 (NO TF)
Fizzles 5
Plasmas 28 (2 flattop disruptions)
========= ==
Shots 35
|
| Session Leader Comments | |||
| Feb 27 2008 09:37:55:760AM | 1080227001 | Joseph Snipes | Shot 1: Good shot. PLH = 0.4 - 0.5 MW with 90 degree current drive phasing. Three bands of fast electron driven modes at 180 kHz, 280 kHz, and 390 kHz from 0.024 to 0.028 s. |
| Feb 27 2008 09:48:35:803AM | 1080227002 | Joseph Snipes | Shot 2: Very weak modes around 400 kHz with only one evident band at 0.024 - 0.026 s. There was 3 ms added gas in the prepuff for this shot. |
| Feb 27 2008 10:02:33:383AM | 1080227003 | Joseph Snipes | Shot 3: Good shot. Three bands of modes from 200 to 400 kHz bursting from 0.024 to 0.029 s. This shot had 4 ms less gas prepuff than shot 1 and somewhat lower density. |
| Feb 27 2008 10:16:48:900AM | 1080227004 | Joseph Snipes | Shot 4: Try reducing OH1 voltage to slow down the early current rise. Got two clear bands of modes and a rather weak lower frequency band. There is one burst out as far as 0.03 s at 352 kHz. |
| Feb 27 2008 11:06:02:253AM | 1080227007 | Joseph Snipes | Shot 7: Modes are almost gone. Current rise is somewhat faster than on shot 4. |
| Feb 27 2008 11:12:37:383AM | 1080227008 | Joseph Snipes | Shot 8: Density is higher and the current rise is faster. No high frequency modes. |
| Feb 27 2008 11:26:17:963AM | 1080227009 | Joseph Snipes | Shot 9: Return to the current rise from shot 4 and raise Bt to 5.7 T. Disrupted at 1.03 s. Good high frequency modes with somewhat higher frequencies than at 5.4 T as expected for Alfven eigenmodes. |
| Feb 27 2008 11:44:43:140AM | 1080227010 | Joseph Snipes | Shot 10: No modes. The gas prepuff was dropped by 2 ms down to 20 ms. Perhaps, the current profile and mode stability is very sensitive to the prepuff. |
| Feb 27 2008 11:49:02:240AM | 1080227011 | Joseph Snipes | Shot 11: Returned prepuff to 22 ms duration. There are a few very weak modes around 400 kHz between 0.024 and 0.030 s. |
| Feb 27 2008 12:14:01:097PM | 1080227012 | Joseph Snipes | Shot 12: Try increasing the prepuff. There are two bands of modes around 300 and 400 kHz. |
| Feb 27 2008 12:28:01:050PM | 1080227013 | Joseph Snipes | Shot 13: Increase prepuff to 31 ms. Two clear bands of modes and a weak lower frequency band at 178 kHz, 275 kHz, and 378 kHz. The frequencies are lower at higher field, but we need to check the n numbers to see if there is a problem with the Alfven scaling. No HXR data for this shot. |
| Feb 27 2008 12:33:50:963PM | 1080227014 | Joseph Snipes | Shot 14: Increase prepuff to 34 ms. Fizzle. Too much prepuff. There are nonetheless four clear bands of modes starting at 0.01 s until 0.028 s, but they do not burst as the LH driven modes do. |
| Feb 27 2008 12:51:27:077PM | 1080227015 | Joseph Snipes | Shot 15: TF up to 5.95 T. TF is ramping a fair amount during the time when the modes are expected, but there are no modes present. |
| Feb 27 2008 01:08:05:203PM | 1080227016 | Joseph Snipes | Shot 16: TF up to 6.05 T. TF is still ramping during the modes due to a physop error. LHCD assisted startup. Very strange startup shifted the current rise, density rise, and mode onset timing. There are two clear bands of modes from 0.031 to 0.036 s in the range from 200 to 400 kHz. |
| Feb 27 2008 01:18:40:030PM | 1080227017 | Joseph Snipes | Shot 17: Started TF 0.2 s earlier to reach flattop in time for the LH pulse. Reached 6.25 T. There were three bands of modes though the lower frequency band is delayed and somewhat weaker with frequencies in the range of 200 to 400 kHz. |
| Feb 27 2008 01:28:22:900PM | 1080227018 | Joseph Snipes | Shot 18: Reduced prepuff to 25 ms. Still a slow current rise with delayed modes starting at 0.03 and going to 0.034 s in the range of 170 to 400 kHz. |
| Feb 27 2008 02:11:37:013PM | 1080227019 | Joseph Snipes | Shot 19: Reduced prepuff to 20 ms. Faster current rise. Modes have gone away, though there are some modes present before the LH pulse and even what looks like an Alfven cascade at breakdown at 0.005 s. |
| Feb 27 2008 02:11:53:340PM | 1080227020 | Joseph Snipes | Shot 20: Go to 5.1 T with 22 ms prepuff. Good shot with three very clear bands of modes from about 150 kHz to 400 kHz. |
| Feb 27 2008 02:12:00:530PM | 1080227021 | Joseph Snipes | Shot 21: Try 4.8 T. Fizzle! |
| Feb 27 2008 02:26:17:670PM | 1080227022 | Joseph Snipes | Shot 22: Try 4.8 T again. Two bursts between 0.024 and 0.026 s at 300 kHz. |
| Feb 27 2008 02:31:21:600PM | 1080227023 | Joseph Snipes | Shot 23: Try 4.8 T again with a 22 ms prepuff. Fizzle again. |
| Feb 27 2008 03:00:22:553PM | 1080227024 | Joseph Snipes | Shot 24: Reload segment 1 from shot 20 at 5.1 T and increase PLH to 0.75 MW. Only got 0.6 MW ramping up from 0.02 s so that it only reaches max power by 0.024 s. Two bursts at 300 kHz between 0.026 and 0.028 s. |
| Feb 27 2008 03:07:56:797PM | 1080227025 | Joseph Snipes | Shot 25: Increase LH power and start it at 0.015 s to reach peak power sooner. Good shot. Reached 0.8 MW. Three bands of modes from 100 kHz to 300 kHz. Frequency appears to decrease with increasing LH power compared to shot 20 at the same toroidal field!?
|
| Feb 27 2008 03:15:59:663PM | 1080227026 | Joseph Snipes | Shot 26: Fizzle. |
| Feb 27 2008 03:33:19:187PM | 1080227027 | Joseph Snipes | Shot 27: Increase LH power to maximum. Good shot up to about 1 MW. Three bands of modes between 150 and 400 kHz from 0.018 to 0.026 s. |
| Feb 27 2008 03:46:44:530PM | 1080227028 | Joseph Snipes | Shot 28: Decrease LH power. Good shot. Got 0.375 MW. Two bands of modes from 200 to 370 kHz from 0.02 to 0.027 s. |
| Feb 27 2008 03:56:57:167PM | 1080227029 | Joseph Snipes | Shot 29: Decrease LH power some more. Got just under 0.2 MW and no modes. |
| Feb 27 2008 04:07:01:927PM | 1080227030 | Joseph Snipes | Shot 30: LH set to 60 degree phasing. A few modes between 0.026 and 0.03 s between 300 and 500 kHz with just over 0.4 MW of LH power. |
| Feb 27 2008 04:13:22:403PM | 1080227031 | Joseph Snipes | Shot 31: Fizzle! |
| Feb 27 2008 04:30:43:407PM | 1080227032 | Joseph Snipes | Shot 32: Reduced prepuff. LH again set to 60 degree phasing. Increase LH power to 0.5 MW. LH tripped. No modes. |
| Feb 27 2008 04:42:34:657PM | 1080227033 | Joseph Snipes | Shot 33: LH tripped again. No modes. |
| Feb 27 2008 05:00:26:847PM | 1080227034 | Joseph Snipes | Shot 34: Try again with 60 degree phasing starting the LH pulse at 0.017 s. Good shot. There are two bands of modes from 200 to 350 kHz from 0.024 s to 0.032 s though the upper frequency band is rather weak. There are also some weak modes around 600 kHz. |
| Feb 27 2008 05:15:31:740PM | 1080227035 | Joseph Snipes | Shot 35: 120 degree phasing. Got 0.6 MW. No modes. |
| Physics Operator Comments | |||
| Feb 27 2008 07:27:29:310AM | Steve Wolfe | Settting up for 1080227 MP#494 Snipes MP#537 (Piggyback) Marr Load from 1080226003 Import seg2 from 1080225407 (simulation shot) Seg1 setup: leave as is PG4=26msec Rcur offset=1000 Br_0=0 IC_EF4u=-1340 Seg2 (for piggyback): Go ahead and start with a slow sweep, contrary to plan written yesterday. slow down zcur step from 5msec to 20msec (.8 to .82),[-.005,.006] zcur back down to 0 between 1.3,1.5 Add initial row in CLEARIN observer, -3sec; call it change second row to .805, zxa=0.39; call it change third row to 2.802, No zxa spec; Call it Ok the screen. Change wire 11 from ssep to clearin, zero gains, (load wire from wire 10, remove zxa keywords) Use wire 10,11 for monitor of clearin, 12 for ssep. Note that 9-12 is on Ip ref. Just for the hell of it, call the nl04 Load at 27-Feb-2008 07:25:24.00 Open tree /home/wolfe/pcs_scratch -1 Open tree done | |
| Feb 27 2008 09:30:02:893AM | 1080227001 | Steve Wolfe | Shot#1: First plasma attempt ~09:20 (TF cooling slow because of O2 alarms in cell this AM). plasma full length, early non- thermals. LH claims to have worked. SSEP steps from 0 to +6mm, probably need to back initial zcur down a little. Left gap has a small step from 1.4 to 1.65cm SSEP sweep seems to be right on 20msec Joe has modes between .024 and .028sec At 30msec we have 150kA, 1.2e19. Next: increase pg4 to slow down current rise |
| Feb 27 2008 09:43:45:250AM | 1080227002 | Steve Wolfe | Shot#2: increase pg4 from 26ms to 29ms Argon puff from 50 to 150ms. No time to adjust sweep; will do it next time. plasma full length, big marfe after zcur sweep. current rise and density look almost identical IP=141, nl04=1.15e19 Next: reduce pg4 from 29 to 22ms |
| Feb 27 2008 10:01:28:977AM | 1080227003 | Steve Wolfe | Shot#3: decrease pg4 from 29ms to 22ms drag zcur trace down by ~3mm (.000785 to +.003147) still 20msec plasma full length, flashes of marfe? later in pulse. Bouncy startup. Modes are there At 30ms Ip=132, nl04=1.06, p0(t=0)=.06 SSEp excursion from -1.5mm to +4.5mm Next: play with Oh voltage to slow current rise. |
| Feb 27 2008 10:13:37:600AM | 1080227004 | Steve Wolfe | Shot#4: play with Oh voltage to slow current rise. oh1 point @.015 and .02 from 150 to 100V oh2 points @.017 and .026 from 10,15 to 5, 10V No change to pg4 or seg2. plasma full length. Still bounces, but less. Current is lower at time of mode, catches up at .03 Modes a bit longer. Next: reduce gap from 1.4,1.7 to 1cm, reduce OH voltages a bit more. |
| Feb 27 2008 10:27:35:583AM | 1080227005 | Steve Wolfe | Shot#5: oh1_volt at [.01,.015,.02] to [50,50,50] from [90,100,100] oh2_volt at [.012,.017,.026] to [0,0,0] reduce pg4 from 22 to 20 Argon puff to 200msec (MR request) clearin from, .003 to 0 (KMarr request on gap) rcur from .6585 to .657 Need to do a no-power shot, Critical init failure on buslv cpci (I think) |
| Feb 27 2008 10:45:38:433AM | 1080227006 | Steve Wolfe | Shot#6: oh1_volt at [.01,.015,.02] to [50,50,50] from [90,100,100] oh2_volt at [.012,.017,.026] to [0,0,0] reduce pg4 from 22 to 20 Argon puff to 200msec (MR request) clearin from, .003 to 0 (KMarr request on gap) rcur from .6585 to .657 No TF. No plasma. Apparently wouldn't have gotten LH anyway, something wrong with LH computer. Probably associated with restarting the cycle? |
| Feb 27 2008 10:59:58:213AM | 1080227007 | Steve Wolfe | Shot#7: oh1_volt at [.01,.015,.02] to [50,50,50] from [90,100,100] oh2_volt at [.012,.017,.026] to [0,0,0] reduce pg4 from 22 to 20 Argon puff to 200msec (MR request) clearin from, .003 to 0 (KMarr request on gap) rcur from .6585 to .657 plasma full length current rise is faster than shot#4, p0 down to .053, Modes look worse. Almost no bounce. Density is down. Left gap is 1.2cm before sweep, could come down in. Next: Drop voltage another 50V on OH1 |
| Feb 27 2008 11:12:05:337AM | 1080227008 | Steve Wolfe | Shot#8: oh1_volt at [.01,.015,.02,.035] to [0 0 0 0] from [90,100,100,?] oh2_volt at [.012,.017,.026] to [-10,-10,-10] Argon puff to 200msec (MR request) clearin from, 0 to -.002 (leave rcur) plasma full length, still flashing during upper null phase. Current rise still fast, no modes at all. There is a small cIII increase at .022 that seems to raise the density a little. Next: Back to shot#4 for startup. |
| Feb 27 2008 11:24:34:757AM | 1080227009 | Steve Wolfe | Shot#9: Back to shot#4 for startup. Raise TF from 150 to 158ka (5.7) PG4 is at 22msec. Could decrease the EF1 currents a few amps, but leave it. The clearin error seems to be nearly constant across the sweep, but it's no-zero (~2500). Don't understand why. Try speeding up the sweep to 10msec Raise Argon to 300msec plasma disrupts at 1.04sec. Marfes at 0.5sec Joe's modes are clearer, and frequency is higher. But he complains the current rise is fast again. Next: drop zcur another 3mm and increase Bt to 6.0T |
| Feb 27 2008 11:41:12:747AM | 1080227010 | Steve Wolfe | Shot#10: increase Bt to 6.0T (TF to 166.7kA), decrease final zcur to 0 (from ~.003) drag it all down. Decrease pg4 from 22 to 20 (disruption recovery) Disruption at 0.89sec, persistent runaways after the LH. Reduce Argon back to 200msec. Move rcur in by another 1mm There is a vertical thrash at 0.8sec Modes are gone. Repeat this shot (in seg1) |
| Feb 27 2008 11:53:21:510AM | 1080227011 | Steve Wolfe | Shot#11: Reduce Argon back to 200msec. Move rcur in by another 1mm PG4 back to 22msec. Probably should have moved the zxa change time from .805 to .810, but too late. There was a thrash in clearin on #10. plasma full length. Next: speed up the sweep to 10msec raise pg4 |
| Feb 27 2008 12:03:03:630PM | 1080227012 | Steve Wolfe | Shot#12: speed up the sweep to 10msec .810sec, leave zxa at .805 raise pg4 from 22 to 26msec, still at 6.0T, trying to slow current rise. Plasma full length, current rise same, maybe a little slower Modes almost gone. SSEP change is ok in 10msec Next: decrease pg4 or maybe increase it. SL is waffling |
| Feb 27 2008 12:18:30:807PM | 1080227013 | Steve Wolfe | Shot#13: Increazse pg4. 26-> 31msec No seg2 changes this time. plasma full length. current rise may be slower. Mode frequensies are lower. Next: Up to 6.3T May need to raise the upper value on zcur, JR says they've stopped seeing the rotation change. |
| Feb 27 2008 12:32:01:227PM | 1080227014 | Steve Wolfe | Shot#14: Up to 6.3T (175kA), pg4 from 31 to 34msec Increase upper value of zcur ramp from 4.5e-5 to .005 (total sweep will be -.011 to +.005 in 10msec) No change in zxa timing. Fizzle. Maybe 34msec was too much. P0=.095mTorr On the other hand, Joe sees 4 sets of modes. |
| Feb 27 2008 12:51:28:810PM | 1080227015 | Steve Wolfe | Shot#15: Up to 6.3T (175kA), pg4 from 34 to 31msec Increase upper value of zcur ramp from 4.5e-5 to .005 (total sweep will be -.011 to +.005 in 10msec) No change in zxa timing. plasma full length (survived the sweep, assuming I loaded it). Some hash on the halpha during the upper null phase. Modes have gone away. SSEP excursion seems to be from -2.5 to +7mm (oversjoot) then back to +4mm or so. Next: Start TF at -1.2sec instead of -1.0 (we aren't getting to flattop at time of Joe's interest) |
| Feb 27 2008 01:03:07:450PM | 1080227016 | Steve Wolfe | Shot#16: Start TF at -1.2sec instead of -1.0 (we aren't getting to flattop at time of Joe's interest) Reload seg2 from shot 3, trying to reproduce the shot when Hirex saw velocity change Forgot to move the TF waveform in seg1 earlier (Looked at the seg2 one that starts at -1.5 for some reason). Operator error. Bad startup, but got modes. Current very slow, seems to hit inside around 0.22, then takes off with the LH. Velocity change is back, as is the marfe. Next: Program TF up from -1.2, decrease pg4, decrease inner gap. |
| Feb 27 2008 01:15:09:120PM | 1080227017 | Steve Wolfe | Shot#17: Start TF at -1.2sec instead of -1.0 PG4 from 31 to 29msec Decrease inner gap, per KMarr Clearin from .003 to -.002 rcur to .656 from .6585 plasma full length. Still marfes while upper null. Still a slow current rise in startup. I think the LHCD is saving these from dying inside. Current at .02sec is only 65kA. Inner gap goes from 1cm to 1.4cm after zcur Joe sees modes, frequencies did not go up. Next: lower pre-puff again. |
| Feb 27 2008 01:26:43:413PM | 1080227018 | Steve Wolfe | Shot#18: lower pre-puff again. pg4 form 29 to 25msec Sweep in 10msec instead of 20ms (-7.85 to +3.15mm ZCUR) plasma full length, Still very slow current rise. Modes are there after .03sec Next: reduce pg4 again to 20msec. |
| Feb 27 2008 01:43:39:713PM | 1080227019 | Steve Wolfe | Shot#19: lower pre-puff again. pg4 form 25 to 20msec Start zcur at -.013 (from -7.853e-3), leave upper at +.003147 Faster current rise, higher density, modes are gone. SSEp goes -5mm to +5mm, then slides up some more Next: 5.1T, TF start time back to -1.0sec, pg4=22msec |
| Feb 27 2008 01:56:38:293PM | 1080227020 | Steve Wolfe | Shot#20: 5.1T (141.7kA), TF start time back to -1.0sec, pg4=22msec Decrease seg 2 density from 8 to 7e19. Plasma full length. So-so current rise, aided by LHCD. Joe sees "very nice" modes. Density didn't come down much, marfe is still there, but smaller. Next: decrease Bt again to 4.8T |
| Feb 27 2008 02:09:06:993PM | 1080227021 | Steve Wolfe | Shot 21: decrease Bt again to 4.8T (133kA) Move clearin observer switch time from .805 to .810, see if gap is better. Fizzle. Moves in, doesn't make it to LH time. Next: drop pg4 from 22 to 20msec, increase EF1 current by 100A |
| Feb 27 2008 02:25:41:013PM | 1080227022 | Steve Wolfe | Shot 22: drop pg4 from 22 to 19msec, increase EF1 current by 100A 5900 -> 6000A (if we go back up in TF remember to put this back) Go back to 150V on OH1 at 15,20msec, leave OH2's as is. Still trying for 4.8T with clearin observer switch time from .805 to .810, see if gap is better. Plasma full length. Clean current rise. There's a spike on H-alpha at .8sec, EFC current gets a spike near floor. Nothing very different on the actual gap thrash, Next: Brock will inject at 1.4sec, raise pre-puff back to 22msec |
| Feb 27 2008 02:33:02:960PM | 1080227023 | Steve Wolfe | Shot 23: Brock will inject at 1.4sec, raise pre-puff back to 22msec Move clearin observer switch to .80 just to test. Fizzle. Give up on higher gas at this point Next: import seg1 from shot#20 (5.1T) |
| Feb 27 2008 02:49:47:697PM | 1080227024 | Steve Wolfe | Shot 24: import seg1 from shot#20 (5.1T). Begin power scan (step 2) Still going for pellet at 1.4sec, clearin observer switch at .800sec plasma, with pellet, full length Still marfe's in upper null. No obvious improvement in gap thrash. Short weak modes. Smooth current rise. Next: repeat seg1 with higher LH, try the reverse sweep in zcur? |
| Feb 27 2008 03:03:25:243PM | 1080227025 | Steve Wolfe | Shot 25: import seg1 from shot#20 (5.1T). Begin power scan (step 2) Still go repeat seg1 with higher LH, try the reverse sweep in zcur from 1.1 to 1.110 down to -.005 only. No reverse clearin switch yet. Move third fast efit burst to 1.09sec Plasma, LH fires earlier, big spike on CIII. Marfe goes away when it swings back down at 1.1sec Brock's pellet shows up on schedule at 1.4sec SSEP going down is from 1.100 to 1.110 with little overshoot, goes from +7.2mm to +1.6mm, never goes negative. Both gaps drop. Joe has modes, although rf tripped Next: LH to higher power. |
| Feb 27 2008 03:26:32:147PM | 1080227027 | Steve Wolfe | Shot 27: Decrease pg4 from 22 to 20msec Import seg3 from seg3 of 1080215001 for locked mode calibration shot. Don't turn it on yet. plasma full length. Next: Change ref rxa for second Clearin from .564 to .544 (closer to actual) (timing is still at .800) LH at low power. |
| Feb 27 2008 03:41:46:850PM | 1080227028 | Steve Wolfe | Shot 28: Change ref rxa for second Clearin from .564 to .544 (closer to actual) (timing is still at .800); same change for wire 10. LH to low power. plasma full length. No pellet Gap still gets bigger going up, smaller going down. Next: Move RXU program to zero, put ref rxa back to nominal |
| Feb 27 2008 03:53:14:630PM | 1080227029 | Steve Wolfe | Shot 29: Move RXU program to zero from -.015, put ref rxa back to nominal on second row of wire 4 and on wire 10. Trying to symmetrize upper and lower, per Brian. LH to lower power for Joe. Disrupts at .43sec at crossover. Was it the RXU change? Looks like it touches on the outside. OH1 crowbarred. Joe got no modes. Next: Move rcur in at .37sec |
| Feb 27 2008 04:10:32:023PM | 1080227030 | Steve Wolfe | Shot 30: Drop pg4 from 20 to 19msec Move rcur in at .37sec from .6585 to .656, Try to avoid outer thrash at crossover. If this disrupts I'll put RXU back Begining phase scan, no seg1 change except pg4 Disrupted at .87sec; doesn't seem to like the lower triangularity upper null? Seems to be going vertically unstable. We're getting a a big excursion on EF2L voltage at 0.80 Next: repeat seg1 with more power. reload seg2 from #28. |
| Feb 27 2008 04:13:08:870PM | 1080227031 | Steve Wolfe | Shot 31: repeat seg1 with more power, same phase reload seg2 from #28 and hope it doesn't disrupt fizzle. Next: reduce pg4 again |
| Feb 27 2008 04:29:21:797PM | 1080227032 | Steve Wolfe | Shot 32:pg4 from 19 to 17msec repeat seg1 with more power, same phase reload seg2 from #28 and hope it doesn't disrupt There is a loud buzzing coming from the PEI (or something) in the power room. Gary and Bill will investigate (later). plasma full length, with pellet Got the zcur sweeps back. LH seems to have faulted. |
| Feb 27 2008 04:43:43:983PM | 1080227033 | Steve Wolfe | Shot 33: repeat. Holding off on locked mode shot until Joe gets closer to finishing the run plan (On next to last phase point now). plasma to 1.6sec, with pellet; may have been unhappy after the pellet. Marfe looks bigger this time, no good reason. LH seems to have faulted again. Next: repeat again, LH will try turning on at 17msec instead of 0 |
| Feb 27 2008 04:59:44:580PM | 1080227034 | Steve Wolfe | Shot 34: repeat. Holding off on locked mode shot until Joe gets closer to finishing the run plan (On next to last phase point now). Change down zcur sweep to 5msec long, +3 to -5mm Reduce pg4 from 17 to 16msec plasma disrupted at 1.55 again. LH stayed on. ZCUR -8mm in 5msec seems to have worked, maybe a little slower than programmed. EFC does not seem to rail Next: 120degree, do locked mode shot |
| Feb 27 2008 05:09:14:687PM | 1080227035 | Steve Wolfe | Shot 35:Go to 120degree, do locked mode shot PG4 from 16 to 15msec, seg2 off, seg3 (lm shot) on. Plasma full length with pellet. Not sure we got the locked mode. Seems to have locked from .75 to 1.0, then unlocked again. Density didn't fall as much as usual. LH stayed on, but no modes. Maybe it means something? Not many fast electrons. END OF RUN. |
| Engineering Operator Comments | ||||
| Shot | Time | Type | Status | Comment |
| 1 | 09:19:49:980AM | Plasma | Ok | |
| 2 | 09:36:53:243AM | Plasma | Ok | |
| 3 | 09:54:42:437AM | Plasma | Ok | |
| 4 | 10:09:04:623AM | Plasma | Ok | |
| 5 | 10:25:19:737AM | Plasma | Bad | No Power shot, critical failure during init |
| 6 | 10:40:53:647AM | Plasma | Bad | TF did not fire |
| 7 | 10:53:14:097AM | Plasma | Ok | |
| 8 | 11:06:40:003AM | Plasma | Ok | |
| 9 | 11:19:30:877AM | Plasma | Ok | |
| 10 | 11:32:12:627AM | Plasma | Ok | |
| 11 | 11:44:56:453AM | Plasma | Ok | |
| 12 | 11:57:30:513AM | Plasma | Ok | |
| 13 | 12:14:32:143PM | Plasma | Ok | |
| 14 | 12:27:06:190PM | Plasma | Ok | |
| 15 | 12:42:45:893PM | Plasma | Ok | |
| 16 | 12:55:17:143PM | Plasma | Ok | |
| 17 | 01:08:14:533PM | Plasma | Ok | |
| 18 | 01:20:45:080PM | Plasma | Ok | |
| 19 | 01:36:02:503PM | Plasma | Ok | |
| 20 | 01:50:11:550PM | Plasma | Ok | |
| 21 | 02:04:23:723PM | Plasma | Ok | |
| 22 | 02:16:57:143PM | Plasma | Ok | |
| 23 | 02:29:22:910PM | Plasma | Ok | |
| 24 | 02:41:50:703PM | Plasma | Ok | |
| 25 | 02:54:57:453PM | Plasma | Ok | |
| 26 | 03:07:25:437PM | Plasma | Ok | |
| 27 | 03:19:52:340PM | Plasma | Ok | |
| 28 | 03:32:51:793PM | Plasma | Ok | |
| 29 | 03:45:49:510PM | Plasma | Ok | OH1 Self Power Circuit Fired Generated by Plasma Disruption |
| 30 | 03:58:18:963PM | Plasma | Ok | |
| 31 | 04:11:00:323PM | Plasma | Ok | |
| 32 | 04:23:27:260PM | Plasma | Ok | |
| 33 | 04:37:08:557PM | Plasma | Ok | |
| 34 | 04:49:59:163PM | Plasma | Ok | |
| 35 | 05:02:25:240PM | Plasma | Ok | |
| System Availability | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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