| Miniproposals | ||||||||||
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| Operators | |
| Session leader(s): | Amanda Hubbard |
| Physics operator(s): | Steve Wolfe |
| Engineering operator(s): | Bill Parkin,Ed Fitzgerald,Gary Dekow |
| Engineering Operator Run Comment |
| automatically entered by signon - please replace with real comment |
| Session Leader Plans |
| Entered: Sep 9 2010 02:35:42:580PM |
| Author: Amanda Hubbard |
| Run plan for 1100910. MP 613: LHCD into higher Te, high confinement plasmas
aka "LHCD into I-mode or bust." *** RUN WILL START AT 8 AND END AT 3 *** Session Leader Amanda Hubbard Physics Operator Steve Wolfe Required: cryopump, ICRF, LHCD, DNB. ETS (possibly will need change in fibre positions), ECE. Neon available for puffing in case of tile heating or ICRF difficulties. Desired: MSE, CXRS This run will follow up on 1100813, in which we coupled LH into ICRF heated L-modes, but failed to make an I-mode at the chosen conditions (1.1 MA). A large part of the reason was unexpected difficulty combining LHCD with E-port ICRF, severely restricting the power to that from J-port. We also tried to cover several configurations in one run day. The next attempt will be informed by recent runs 1100817, which made I-modes at 0.8 and 1.1 MW, and 1100912, which showed a consistent increase in non-thermal emission with small inner gap. To maximize chances of success, we will first make a suitable I-mode target, then take the time needed to couple LHCD to it (proceeding somewhat in parallel). Then try to move to higher Ip, hotter, I-modes. Step 1. Optimize 800 kA I-modes for LHCD Start by reproducing a good, moderate ne and power I-mode 1100817019 (USN, 5.65 T, 0.8 MA). Got prompt I-mode with 3 MW ICRF at nebar 1.4e20m-3 (programmed target was a little lower). This time ramp ICRF 2-3.5 MW. Once I-mode is achieved, reduce target density shot to shot to find minimum for I-mode density, and reduce ICRF power to minimum needed (ideally all J-port). Step 2. Inject LHCD into steady I-mode. May well require few shots to adjust launcher position, puff gas etc (we will use edge reflectometer and probes as a guide). Monitor non-thermal ECE, HXR etc. Step 3: Try to increase ICRF power, for a hotter I-mode while maintaining LH coupling (will depend on whether we succeed in combining with E-port. Also try D-port for short period, to see the effect on coupling. Step 4: Shot to shot, decrease inner gap to 3-4 mm, checking I-mode is maintained. Do non-thermals increase as in ohmic target cases? Increase Ip to 0.9 or 1.0 MA. How high will depend on how much success we've had in combinging with E-port, and therefore how much headroom we have on threshold power (which we know increases with Ip). The advantage of higher Ip is that edge and core Te are significantly higher. Repeat some of above steps to optimize I-mode and LHCD, ideally making a significant change to loop voltage. This should bring us to Ron's party... |
| Physics Operators Plans |
| Entered: Sep 10 2010 07:50:51:807AM |
| Author: Steve Wolfe |
| Physop Plan and Engineering setup for Friday, Sept. 10, 2010
MP#613 LHCD Effectiveness in high Te and confinement plasmas SL: Hubbard PO: Wolfe Run begins at 08:00 and ends at 15:00 NOTE: unusual start and ending times! ----------------- Engineering Setup ----------------- Power systems as on: 1100817019 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 DISABLED (PG1) leave B-side upper as is Hybrid DISABLED (PG2) fill B-main with 40 psi D2 Hybrid enabled (PG3) fill H-bottom with 2psi Neon Hybrid DISABLED (PG5) fill NINJA with 10 psi D2 DISABLED Enable gate-valves and shutters: ECE, VUV, HiREX Sr, Xeus Leave z-bolo shutter as is (should be open) Torvac gatevalve toggle (yes/no): no Boronization(yes/no): no Overnight ECDC (yes/no): YES ICRF(yes/no): YES LH(yes/no): YES Cryopump (yes/no): YES - Required for first shot DNB (yes/no): YES Vessel temperature: 50/50/50 ------------------------------ ECDC Parameters (if requested) ------------------------------ gas and pressure: D2 at 2e-4 Torr sweep: 44/45/103 cm scan: 20/120 s Physics Operator Plan: ----------------------- Start from an 800kA shot 1100817019 1) Establish I-mode, bringing up neon puff as indicated (cf #20) According to SL plan, decrease nl04 looking for minimum consistent with I-mode and reduce ICRF to minimum required for I-mode, preferably all power from J-port. 2) Turn on LHCD, monitor non-thermals with the usual tools 3) If there is headroom with J, or we can use E or D along with the LH, try increasing ICRF to get a hotter I-mode 4) Decrease inner gap to ~4mm, as demonstrated to improve LH last week. 5) Increase current (0.9 or 1MA) and adjust ICRF to maintain I-mode |
| Session Leader Summaries |
| Entered: Sep 13 2010 11:02:00:387AM |
| Author: Amanda Hubbard |
| Run summary for 1100910. MP 613: LHCD into higher Te, high confinement plasmas
aka "LHCD into I-mode or bust." Note: easier to read in session summary page Session Leader Amanda Hubbard Physics Operator Steve Wolfe This was a very successful run day and accomplished much of what was hoped for. We coupled LHCD into high Te USN plasmas with ICRF powers up to the L-H threshold, at two currents: 800 kA and 900 kA. It was found that LHCD could be combined with ICRF from J and E port, at N//=1.9. However, reflections increased, and became more noisy, particularly with E-port. Does this reflect increase density fluctuations, and could these be related to SOL losses?? A single attempt late in the run at N//=2.3 had high reflections and trips. LHCD performed well. As on run 1100813, when power was increased about about 0.6 MW we saw tungsten injections(eg shot 10) ; it is conjectured that in conditions of lower core absorption, SOL power is heating the divertor shelf. We therefore limited power to 0.5-0.6 MW, below the max available. Shots 1-16 were at 800 kA. ICRF was progressively increased to the H-mode threshold, which was at about 2.6 MW (eg shots 5, 9). It was noted that the extra power from LHCD often triggered an H-mode, so we started reducing E-port power by the amount of the LH power when it was applied at 1 second. Minor changes were made to density, impurity puffing etc. A good example is shot 11, which had no H-mode transition, and 0.6 MW LH added at 1 second. Core Te reached 4 keV and edge Te about 0.5 keV. It is not clear whether the confinement was L or I-mode; there is a modest edge Te gradient in the edge, but no evident changes in turbulence. Shots 16 and 17 were reference discharges with no ICRF and much colder Te (Te0 1.9 keV, Tedge ~100 eV). Shoty 16 had ICRF, and the inner gap was scanned to smaller values to see the effect on non-thermals, which did not appear large. The remainder of the discharges were at 0.9 MA, scanning ICRF power. At this condition the H-mode transition occurred at 4 MW ICRF (see shot 20) and very hot plasmas were achieved at powers just below this. Best examples are shots 21 and 22, with Te0 > 5 keV, clear edge Te pedestal up to about 0.8 keV (r/a 0.9). Energy confinement was high, with H98 ~ 1.1. In these discharges there was a clear decrease in edge turbulence, (eg reflectometer 75 GHz channel), when ICRF was turned on, indicating a thermal transport barrier and I-mode. However the usual 'weakly coherent mode' at higher frequency was not evident at least on this diagnostic; others remain to be examined. This will be of interest for I-mode physics. The high input power and low densities led to high temps on K-limiter, though no apparent injections. RF and LH pulse lengths were reduced from shot 22 to minimize this. Shot 23 was an attempt at N//=2.3, to ensure full accessibility (though calculations show that N//=1.9 should also be accessible); we got excessive trips due to high R. Shot 24 was an ohmic reference comparison shot, with several LH trips. Shot 25 was at N//=1.9 with ICRF and a small inner gap. This had slightly higher density and was L-mode, with no decrease in turbulence and lower edge Te (about 0.4 keV) and no gradient change. This contrast makes clearer that prior shots were indeed I-mode. Perhaps due to the higher n and/or lower Te, non-thermal emission was reduced. Shot 26 was a locked mode shot for calibration of HIREX rotation, which apparently showed interesting and unusual changes duirng LHCD. To summarize, we obtained a good dataset with which to compare LH effects at different core and pedestal Te, up to values approaching the highest feasible on C-Mod, adding to the 1.1 MA L-mode dataset from 1100813. This will require processing of HXR spectra and careful comparison of achieved densities given the known nonlinear dependence. However, preliminary control room comparison of non-thermal ECE signatures during LHCD (eg GPC2 Ch 6) indicates that any increase in the hotter plasmas is modest. There was also little if any change in loop voltage with LHCD. If borne up by more complete analysis, this would dimish the prospects for advanced scenarios using LHCD. I will add and circulate a more complete list of good shots and time windows soon. |
| Physics Operator Summaries |
| Entered: Sep 13 2010 11:53:56:183AM |
| Author: Steve Wolfe |
Physics Operator Summary for Friday, Sep 10, 2010
MP#613: LHCD in high Te (I-mode)
SL: Hubbard
PO: wolfe
EO: Parkin,
Run time 08:00 to 15:00
The machine ran well today, although cooling was a little slow, and
there were a few delays in cell access because of O2 alarms.
Startups were pretty good. I did the usual amount of fiddling to try to
get rid of bounces and runaways. The bounce seemed to be unusually sensitive
to the IC_EF4 current. Best results, relatively robust, were achieved with
a setting of -1270Amps, used successfully for the last 9 shots as well as some
earlier in the day.
Disruptions in rampdown seemed to be associated with vertical instability
related to increasing li, and were partially ameliorated by running lower
elongation limited rampdowns. The damaged inner wall tile between F and G port
was lighting up on essentially all ramp-ups, and on the limiter ramp-downs,
but did not cause any disruptions and didn't even seem to be sourcing much Mo
during the discharges. We also ran an inner gap scan down to ~zero gap (#16)
and a small gap case (#25).
The final shot of the day (and the FY10 campaign) was a locked mode
calibration shot for the Hirex_SR diagnostic, which disrupted in flattop.
Aside from this shot, the only shot which did not make it into ramp-down was
#2, which was shut down by the dpcs_xjump procedure because of a big runaway
burst in ramp-up.
The main PO difficulty on this run was keeping the density constant from shot
to shot, to better than 1e19, since small changes in nebar seem to have more
of an impact on the LH than major changes in Te, which was supposed to be the
knob being investigated today. Changes in ICRF power and in gap led to
variation in the actual density with identical programming. Setting the
Integral gain on nl04 to 2 (from 1) after 0.6sec seemed to be useful earlier
in the run, but led to some instability later on in the day and was removed on
shot#17. It may actually be useful to do a system id study on the particle
feedback with the cryopump operating to try to come up with a set of PID
gains, using a Zeigler-Nichols sort of method. The problem is that the gain
settings are probably going to be dependent on the target density as well as
the equilibrium (through the connection to the pumping duct), even for
L-mode plasmas.
Cooling was rather slow today, which Gary believes is due to partial blockage
of the sump filters, probably by ice. This will be helped by the warm-up over
the next 3 weeks, one way or another. There were also problems with low oxygen
in the cell which delayed the run a couple of times for cell access, followed
by longer magnet cooling.
The data system was pretty robust, although there was some confusion early in
the day over the status of the HXR system. This turned out to be due to the LH
tree having been left as /NOINCLUDE, further obfuscated by the presence of
test shots which had inadvertantly been given C-Mod shot numbers
(i.e. 1100910001 and 1100910002).
RF ran well up to the 3MW level (E and J only, since the D-antenna is known to
be problematic with LH). The LH ran very reliably at 90degree phasing, but
faulted repeatedly on the one attempt to vary the n||.
We managed some very hot L- and/or I-mode discharges
at 800 and 900kA with H98 in the vicinity of 1.0. There is some controversy
over whether these were "really" I-mode because the fluctuation signatures
were not clearly present, especially at 800kA. At any rate, the temperatures
required for the experiment were obtained. See the SL_SUMMARY for the physics
results.
At the higher RF power and lower densities (nl04 6 to 7e19), one tile on the K-port
limiter reported high temperature and energy flux, into the red on the
display color scale. We reduced the RF pulse length for the last several
shots to try to prevent melt damage. The GH limiter temps did not show any signs of distress,
although the camera view was showing the usual
signature of heating of loosely bound boron films.
Scorecard:
----------
Test/No Power 0
Duds 0
Fizzles 0
Plasmas 26 (one dpcs_xjump abort)
======== ==
Shots 26
Total plasma duration: 45.75 sec
|
| Session Leader Comments | |||
| Sep 10 2010 08:14:27:710AM | 1100910001 | Amanda Hubbard | Good plasma. 5.64 T, 818 kA.
Got ICRF ramp from J, to 1.6 MW, but not E. Not surprisingly, looks like an L-mode. Retune and retry. |
| Sep 10 2010 08:15:10:933AM | 1100910002 | Amanda Hubbard | Short (0.2 s) and non-thermal. |
| Sep 10 2010 08:40:12:173AM | 1100910003 | Amanda Hubbard | Good plasma. RF ramp to near 3 MW, with a trip near the end. Not an obvious I-mode, though there were hints it was heading in that direction after 1 s (2 MW). Went straight to H-mode 1.3 s after the RF trip.
Next shot, square up ICRF at 2.5 MW, might make transients more obvious. |
| Sep 10 2010 09:03:39:503AM | 1100910004 | Amanda Hubbard | Good plasma. Constant ICRF 2.5 MW. Looks like a pretty warm L-mode, not an evident I-mode. Te_95 is about 500 eV, so this might be an I-mode; hard to tell since the transient at the beginning follows an RF trip.
Next shot: Increase ICRF to 3 MW. |
| Sep 10 2010 09:26:04:687AM | 1100910005 | Amanda Hubbard | Good plasma. Programmed 3 MW (J+E). But J is tripping a lot. Yijun reports a big change in coupling, as though it were H-mode, though there isn't a clear H-mode until nearly 0.9 s. Gradual increase in edge Te until the H-mode, but the transition value is about the Te we got on shot 4. This indicates we were about at the limit.
Next shot: Go back to power of shot 4 (2.5 MW). And add some LH (or try to) late in the flat top. |
| Sep 10 2010 09:46:01:263AM | 1100910006 | Amanda Hubbard | Good plasma. RF stays on, until a late H-mode (> 1.2 s) which is likely triggered by the lower hybrid.
I think this is I-mode or as close as we are going to get at this target condition. Edge Te 500 eV, H98 only 0.8 (and H89 only 1.17). Good news is LH stays on even with 1 MW E-port. Bad news is it inconveniently causes an H-mode (which presumably means that power is getting in). Next shot try to use more J and less E, and turn E off earlier to see effect on LH coupling. |
| Sep 10 2010 09:55:12:280AM | 1100910007 | Amanda Hubbard | J-port tripped a lot at the higher power. Plasma was a little cooler generally; no H-mode. LH stayed on at 0.3 MW level, Greg reports R is lower without E, but acceptable.
next shot: Move LH earlier, go back to 1.5 J + 1 E, reduce target density. |
| Sep 10 2010 10:18:10:053AM | 1100910008 | Amanda Hubbard | Good. RF steady, LH on at 1.0 secs and couples OK, until it makes an H-mode.
Getting clear increase in ECE, including some non-thermal (see eg GPC2 Ch 6 today). Maybe also an inrease in Te, which is likely triggering the H-mode. Next shot: reduce E-port by 1 MW when LH turns on, hopefully avoiding the H-mode. Also modifying shape. |
| Sep 10 2010 10:30:07:770AM | 1100910009 | Amanda Hubbard | Good. An early H-mode with ICRF only, but L or I mode before LHCD comes on.
Good news is significant non-thermals with LH, at nebar=1.3 s. Repeat with more LH power. |
| Sep 10 2010 10:55:12:103AM | 1100910010 | Amanda Hubbard | LH coupled up to 0.8 MW. But we got a big W injection (perhaps due to unabsorbed power hitting shelf? Or was it the shape tweak? Also got an H-mode, and lower non-thermals.
Back off to about 0.6 MW LHCD. And reduce ICRF by 0.6 when it comes on. We will also reduce the inner gap a little. |
| Sep 10 2010 11:09:46:123AM | 1100910011 | Amanda Hubbard | Good reference shot for this run: Power and target plasmas stayed nice and steady. Edge Te was about 500 eV before LH, similar to prior shots. Not a really clear I-mode, unfortunately.
Did get non-thermal ECE when LH on, about 1 keV. Not as strong as shot 9. Note nebar rises a little with LH, to nebar =1.35. For those monitoring edge Te, note that the channels at r/a =0.95 (eg FRCECE ch 4, GPC Ch 9) are getting a non-thermal contribution. Ones further in (eg GPC ch 8) appear to be thermal. |
| Sep 10 2010 11:28:52:443AM | 1100910012 | Amanda Hubbard | Reduced target density. Edge Te is actually lower now, looks less like an I-mode.
Go back to ne of shot 11, turn off argon. After that we may want to increase ne, see if a classic I-mode appears. |
| Sep 10 2010 11:42:13:163AM | 1100910013 | Amanda Hubbard |
Basically a repeat of shot 11. Reducing Argon did not raise edge Te (if anything a little colder). Got nice steady density, nebar about 1.3. non-thermal Trad 1.5 keV. I think this is high for the density. Next shot we will turn off LHCD to get a reference for comparison. And reenable Argon. |
| Sep 10 2010 12:04:26:083PM | 1100910014 | Amanda Hubbard | Ohmic target reference. Trad up to 2 keV (higher) but nel dropped to 1.2e20. Transiently was 1.34, when Trad was 0.5 keV; lower than shots 11 (about the same as shot 13, which for some reason was lower).
Given it is so ne-sensitive, repeat with higher target ne. |
| Sep 10 2010 12:16:53:057PM | 1100910015 | Amanda Hubbard | Ohmic target. Got a lot of MARFEing at the higher ne. LH on part of the time, nebar 1.4e20 and higher. Essentially no non-thermals.
Go back to ICRF, move LH a bit earlier (0.95) and program an inner gap scan as per Greg's run to see if non-thermals increase. |
| Sep 10 2010 12:41:13:533PM | 1100910016 | Amanda Hubbard | ICRF target. Edge Te again 500 eV (L or I-mode?). Not very high non-thermals in gap scan, perhaps due to higher (and rising) density at the same time. A lot of shot to shot variation unfortunately. But if there is a gap effect it is not large.
Next: Increase Ip to 0.9 MA in the hopes of a clearer I-mode. |
| Sep 10 2010 12:52:15:593PM | 1100910017 | Amanda Hubbard | 0.9 MA. 2.5 MW ICRF, 0.6 MW LH. Looks like L-mode, big injection at 1 sec (from LH launcher?)
Significant non-thermals (0.8 keV on GPC2_6) at nebar 1.38 Repeat with higher ICRF. |
| Sep 10 2010 01:11:30:427PM | 1100910018 | Amanda Hubbard | 0.9 MA. 3 MW ICRF, 0.6 MW LH. Much cleaner.
Still not an evident I-mode (or H-mode). So increase power. Edge Te about 500 eV. Non-thermals 1.4 keV @ nebar 1.27. Note H98 is close to 1 before LHCD, and there is some Te barrier. But no fluctuation signature. |
| Sep 10 2010 01:18:24:933PM | 1100910019 | Amanda Hubbard | 0.9 MA. 3.5 MW ICRF, 0.6 MW LH. Much cleaner.
Good shot, but still not an evident I-mode (or H-mode). So increase power. Edge Te about 500 eV. Non-thermals 1.8 keV @ nebar 1.29, an increase. Increase ICRF, and nel a little; have a feeling we are close to I-mode now. Edge Te is about 700 eV, with a clear gradient. |
| Sep 13 2010 09:20:34:233AM | 1100910020 | Amanda Hubbard | Good 900 kA shot, with some short H-mode phases and also some hot L or I mode phases. 3.8 MW ICRF, tripping during H-modes. Appears we have found the upper limit for I-mode. |
| Sep 10 2010 01:56:06:987PM | 1100910021 | Amanda Hubbard | 0.9 MA. 4.0 MW ICRF, 0.6 MW LH.
Very good shot. I'd call it an I-mode. H98 > 1, turbulence drops, though no WCM appears. And edge Te is roughtly 1 keV (broad "pedestal"; Te9 is 580 eV) K limiter is also smoking, unfortunately. So we will shorten up LH and ICRF pulses for the next shot. |
| Sep 10 2010 02:14:06:287PM | 1100910022 | Amanda Hubbard | 0.9 MA. 4.0 MW ICRF, 0.6 MW LH.
Well, we have succeeded in coupling LHCD into a hot, high confinement plasma. Te0 5.5 keV, edge Te roughly 1 keV. And H98=1.1 ; whether or not we call this an I-mode (I tentatively do) it is a good LH target. The non-thermal signatures are there but not large; Te6 1.3 keV at nebar 1.37. Next shot LH will increase N// to make sure it is accessible. |
| Sep 10 2010 02:43:42:053PM | 1100910023 | Amanda Hubbard | 0.9 MA. 4.0 MW ICRF,
Tried N//=2.3 but it tripped out pretty badly. Possibly due to E-port but we don't have enough shots left to explore. |
| Sep 10 2010 02:47:38:083PM | 1100910024 | Amanda Hubbard | 0.9 MA. LH only. N// 1.9
LH tripped a lot, but I think there are periods long enough to be usable. And an overlapping ne range; nebar 1.25 to 1.32. First order result is Te6 up to 1 keV. Not very different from the hot plasmas. But we need to analyse properly since it is so ne-dependent. |
| Sep 10 2010 03:06:28:840PM | 1100910025 | Amanda Hubbard | 0.9 MA. LH only + 4 MW ICRF. N// 1.9
Tried small inner gap, 2-4 mm. Ran well, but nebar ended up higher, up to 1.6e20. Likely as a result, non-thermals were lower, 0nly 0.3 keV. And edge Te is also much lower. about 0.5 keV. This shot has a much different fluctuation spectrum, standard L-mode turbulence. And H98 down to 0.7. So we indavertly got our L-mode comparison. Though not very definitive a comparison of LHCD vs gap. Next shot: Locked mode calibration shot for HIREX guys. Everyone else can go to the party now. |
| Sep 10 2010 03:18:52:347PM | 1100910026 | Amanda Hubbard | Got the locked mode shot - though it disrupted a bit after LM.
That's all for the FY10 campaign, thanks, everyone! |
| Physics Operator Comments | |||
| Sep 10 2010 07:33:04:177AM | Steve Wolfe |
Setting up for MP#613:LHCD in I-mode
SL: Hubbard
PO: wolfe
Startup from yesterday looks ok, except pg4=40msec seems too low.
Import seg 2 from 1100817019 seg2
change title to 800kA upper null
note: nl04 programmed 8e19,
zcur=-.005, may want to raise back to 0
RXU -.015, ZXU=+.015
Turn on seg2, off seg3 !
Changes:
Seg1: Pg4 from 40 to 45msec
Leave rcur offset 3500, BR_0=0, EF4=-1280
Seg2: Acoil_cur last point from 30A to 0 (??)
dpcs_piezo_chopper OUTPUTS to ["pulse_gas3","H-bot"] (prepare for adding neon)
Load at 10-Sep-2010 07:32:09.00
| |
| Sep 10 2010 08:07:50:080AM | 1100910001 | Steve Wolfe | Shot#1: Enable bside-lower for first shot (75msec Argon) plasma full length, early marfe no runaways, startup ok, bz looks positive, br negative J ramps to 1.6MW, with a couple of dropouts nl04 drops to 7e19, after overshoot, gas is on through EOF, may need more gain. Next: BR_0 from 0 to .0005 EF4 from -1280 to -1290 Increase I gain on nl04 from 1 to 2 after 0.6sec |
| Sep 10 2010 08:19:34:693AM | 1100910002 | Steve Wolfe | Shot#2: BR_0 from 0 to .0005 EF4 from -1280 to -1290 Increase I gain on nl04 from 1 to 2 after 0.6sec Leave early pg3 alone, see if marfe changes on its own Big runaway burst early. Xjump shutdown looks like some early injections, current got to 600kA, first bounce may be at .01sec, then a big one after .03sec Next: ef4 back to -1280 |
| Sep 10 2010 08:36:23:043AM | 1100910003 | Steve Wolfe | Shot#3: EF4 from -1290 to -1280 Drop pg3 in seg1 from 60 to 40 after .01sec probably should have increased pg4, but maybe the disruption will take care of it plasma full length, nice and quiet, no marfe, looks like one rf fault, one h-mode (not necessarily in that order) E-port ran this time, rf gets to 2.8MW, with some faulting We're diverting around .31sec, inner wall tile is lighting up, but not exploding. RF is coming on .6sec, just into flattop. Next: square up the rf power |
| Sep 10 2010 08:44:44:173AM | 1100910004 | Steve Wolfe | Shot#4:square up the rf power No dpcs changes, although I'm tempted to raise pg4 some more Result: plasma full length, some early runaways, big bounce no h-mode this time, possible I-mode ? Next: increase pg4 from 45 to 50msec |
| Sep 10 2010 09:21:47:830AM | 1100910005 | Steve Wolfe | Shot#5:increase pg4 from 45 to 50msec Reduce clearin sweep to wall in rampdown, since inner wall lights up again Increasing RF to 3MW Cell access for Greg, Jerry, the polar bears, etc. Also lab access for Amanda Low Oxy alarm in cell again, pump turned off; there seems to be an exhaust problem this week? TF cooling after cell access takes to 27minutes in recool then cryo had to cool down again; INIT at 30 minutes Result: plasma full length, couple of h-modes no runaways, rf highly variable Stays diverted to 1.76sec Next: reduce rf, fire LH late in discharge, no dpcs changes |
| Sep 10 2010 09:33:34:363AM | 1100910006 | Steve Wolfe | Shot#6: reduce rf, fire LH late in discharge, no dpcs changes Result: plasam full length, some early runaways, bounce H-mode around 1.25 during LH Bit of a marfe or injection just after RF comes on, otherwise pretty quiet; some rf trips early and late. LH trippy as well. Possible I-mode (?) Next: increase pg4, 10Amps positive on ef4 SL directing RF changes |
| Sep 10 2010 09:50:56:477AM | 1100910007 | Steve Wolfe | Shot#7: increase pg4 from 5to 55msec, EF4 from -1280 to -1270 Try ICRF from J only, no seg2 changes yet. plasma to 1.6sec, disrupts in rampdown, looks like it went vertically unstable injection at 1.15sec Actually had both J and E, J faulting at 2MW; LH stays on Next: reduce nl04 from 8 to 7e19 |
| Sep 10 2010 10:09:44:083AM | 1100910008 | Steve Wolfe | Shot#8: reduce nl04 from 8 to 7e19 slow down rise of zxl in rampdown, Changes to rf and LH Result: plasma to 1.6sec, 2 h-modes, 1.01 and 1.46sec ICRF steady until H-modes. LH trippy around 500kW Very late breakdown, 9msec, slow current rise. Next: ef4 back to -1280, drop clearin again in rampdown. |
| Sep 10 2010 10:21:03:880AM | 1100910009 | Steve Wolfe | Shot#9: ef4 back to -1280, drop clearin again in rampdown. pg4 from 55 to 50msec; leave br0 for now, although it's drifting +ve Increase triangularity: RXU from -.015 to -.005 plasma full length, early runaways, bounce is back breakdown time is back to normal. H-mode at .8sec or so, Moved the xpoint the wrong way, oprator error. Next: rxu from -.005 to -.025! |
| Sep 10 2010 10:43:23:637AM | 1100910010 | Steve Wolfe | shot#10: rxu from -.005 to -.025, really increase triangularity this time. No startup changes, see if it gases up with no rampdown disruption, before I add the pg4 back. plasma to 1.35sec, injection/marfe kills it Still had early runaways, bounce. LH power was up. Triang was up as intended, Injection at 1.04 and then an H=mode at 1.15sec Matt claims both are W. Could be a probe tip from the top, but it seems to correlate with LH rather than ICRF. Next: raise ef4 and br0, not sure what SL will want for flattop changes |
| Sep 10 2010 11:02:08:140AM | 1100910011 | Steve Wolfe | shot#11: raise ef4 from -1280 to -1275 and br0 down from .0005 to 0, Reduce inner gap 3mm: Clearin from -.0025 to -.0055,Rcur from .6545 to .6530 Less RF power. Result: plasma full length, no runaways, no h-mode, RF clean, LH clean, no obvious CD but SL says there are non-thermals on the ECE Breakdown is a little late again, 7msec Next: EF4 back to -1280 |
| Sep 10 2010 11:17:21:473AM | 1100910012 | Steve Wolfe | shot#12: EF4 back to -1280 NL04 from 7e19 to 6e19 per SL request Result: plasma full length, some early runaways, bounce, bd time back to 5msec Some non-thermals during LH. Next: raise pg4, put nl04 back to 7e19 |
| Sep 10 2010 11:34:18:467AM | 1100910013 | Steve Wolfe | shot#13: pg4 from 50 to 55msec, nl04 from 6 to 7e19 (as on #11) disable bside-lower (no argon this shot) result: plasma full length, still has early runaways and bounce Shot looks very similar, very small drop in Vloop during LH, but there are some non-thermals. Next: one more step in PG4 Ref shot with ICRF off |
| Sep 10 2010 11:55:19:917AM | 1100910014 | Steve Wolfe | shot#14: pg4 from 55 to 60msec, Ref shot with ICRF off, turn argon back on Result: plasma full length, no runaways, no bounce, bd at 6msec Bit of a hesitation between 10 and 15msec. Still getting non-thermals during LH, doesn't seem to notice that Te is down a factor of 2? nl04 is just a tad low before LH, then rises, then sags. All this is within 1e19, but the LH is very sensitive. Next: leave startup alone, raise nl04 target. |
| Sep 10 2010 12:09:55:717PM | 1100910015 | Steve Wolfe | shot#15:leave startup alone, raise nl04 target from 7 to 8e19 plasma full length, marfes Bad bounce but no runaways. Something initiates a marfe at .8sec, but the density feedback doesn't turn off. Looks like it went unstable on the Integral gain? Next: back to density of #14 (7e19) put in a gap scan |
| Sep 10 2010 12:35:12:413PM | 1100910016 | Steve Wolfe | shot#16: back to density of #14 (7e19) put in a gap scan 1cm to 0 between 1.1 and 1.4sec CLEARIN from -.0025 to -.0125 RCUR from .6545 to .6495 raise pg4 from 60 to 65msec Result: early runaways, plasma full length Magnetics errors on f13,f27,bp07jk, bp11jk. May be a real problem? Seems to have gotten the sweep, density is higher by 1e19, up to 8e19 during LH. Next: reduce nl04 Int gain to 1 Remove gap scan, raise Ip to 900kA |
| Sep 10 2010 12:51:58:653PM | 1100910017 | Steve Wolfe | shot#17: reduce nl04 Int gain to 1, increase D from 6 to 10 Remove gap scan: clearin to -.0025, Rcur to .6545 raise Ip to 900kA Leave startup alone, see if it gets better on its own. plasma to 1.65sec, still bounces in startup, runaway dump at .35sec Big Prad increase starts at 1sec, possibly associated with LH. Takes a big bite out of Te, current. mlr claims tungsten. Next: EF4 to -1270 |
| Sep 10 2010 01:04:26:123PM | 1100910018 | Steve Wolfe | shot#18: EF4 to -1270, no seg2 changes plasma to 1.68sec, no bounce no runaways, bd is a little later again A few RF faults, but pretty clean at 3MW before LH, 2.5 during Still seems to be going vertically unstable in rampdown K limiter is getting orange. Next: ramp rcur in more in rampdown |
| Sep 10 2010 01:14:46:003PM | 1100910019 | Steve Wolfe | shot#18: ramp rcur in more in rampdown, No startup changes, no flattop changes. plasma to 1.6sec, marfe in the middle, around .45sec Neuts are up, still no runaways Rampdown is worse, so undo the RCUR move |
| Sep 10 2010 01:43:37:707PM | 1100910020 | Steve Wolfe | shot#20: undo the RCUR move in rampdown; ramp clearin -ve faster raise nl04 from 7 to 8e19 No seg1 changes Result: plasma full length, h-modes during ICRF, Got f13 and f27 warnings again, both 1e-3Wb level No runaways, startup looks ok, a tad late bd. Klim still showing orange/red Inner wall tile is lighting up in rampdown again Nl04 back down to 7e19 |
| Sep 10 2010 01:54:49:993PM | 1100910021 | Steve Wolfe | shot#21: Nl04 back down to 7e19 from 8e19 No startup or rampdown changes Result: plasma full length, no runaways, f27 and f13 warnings up to 1.1e-3 E faults at around .8sec, causing a drop in density and stored energy, but overall hot and not too radiative L/I-mode K limiter is now into the red, we need to back off on RF energy (pulse length) Next drop RF and LH on-times, keep RF at 4MW from .6 to 1.1sec, LH from .8 to 1.1sec |
| Sep 10 2010 02:11:37:277PM | 1100910022 | Steve Wolfe | shot#22: drop RF and LH on-times, keep RF at 4MW from .6 to 1.1sec, LH from .8 to 1.1sec No PCS changes plasma to 1.7sec, Prad is a little higher, gets to H98~1.1, signatures of I-mode not all present (no WCM). Not much in nonthermals K-limiter is still red! Matt's claiming it does drop. Next: Change n||, leave everything else |
| Sep 10 2010 02:23:08:470PM | 1100910023 | Steve Wolfe | shot#23:Change LH n||, leave everything else as on 22 Result: plasma full length, no runaways, Nice square neuts hard pulse, some injections in rampdown LH faulting continuously Couple of small injections, hardly visible on Te0 Next: do an ohmic reference shot, make a tweak on density |
| Sep 10 2010 02:41:55:720PM | 1100910024 | Steve Wolfe | shot#24:do an ohmic reference shot (LH on from .8 to 1.3sec, no ICRF), make a tweak on density, step from 7e19 to 8e19 at 1.0sec, plasma full length, got lh but trippy late Injections during lh Next: try repeating 23 but with a small inner gap |
| Sep 10 2010 02:57:45:003PM | 1100910025 | Steve Wolfe | shot#25:Decrease inner gap: clearin from -.0025 to -.0105, rcur from .6545 to .6505 plasma full length, densuty is up to 9e19, gas mostly off it's all coming from the rf. Prad is high, Not much on non-thermals, LH stays on ok. Te0 is down to ~4keV. Why doesn't the cryo suck when you want it to? Next: locked mode cal shot for HIREX (seg3) |
| Sep 10 2010 03:12:29:407PM | 1100910026 | Steve Wolfe | shot#26: locked mode cal shot for HIREX: turn off seg2 turn on seg3,. which was shot#30 from yesterday. RF off, LH off. This should be LSN 800kA, falling density from 5e19 Acoil on full. Result: plasma to 1sec, locked mode at .74sec End of RUN End of FY10 Campaign! |
| Engineering Operator Comments | ||||
| Shot | Time | Type | Status | Comment |
| 1 | 07:58:23:420AM | Plasma | Ok | |
| 2 | 08:12:16:090AM | Plasma | Ok | |
| 3 | 08:25:43:163AM | Plasma | Ok | |
| 4 | 08:40:22:220AM | Plasma | Ok | |
| 5 | 09:13:01:787AM | Plasma | Ok | |
| 6 | 09:26:06:290AM | Plasma | Ok | |
| 7 | 09:43:55:630AM | Plasma | Ok | |
| 8 | 10:00:00:163AM | Plasma | Ok | |
| 9 | 10:16:19:653AM | Plasma | Ok | |
| 10 | 10:33:59:153AM | Plasma | Ok | |
| 11 | 10:53:53:017AM | Plasma | Ok | |
| 12 | 11:09:37:260AM | Plasma | Ok | |
| 13 | 11:27:15:130AM | Plasma | Ok | |
| 14 | 11:45:43:433AM | Plasma | Ok | |
| 15 | 12:02:54:370PM | Plasma | Ok | |
| 16 | 12:21:41:220PM | Plasma | Ok | |
| 17 | 12:39:49:330PM | Plasma | Ok | |
| 18 | 12:55:13:867PM | Plasma | Ok | |
| 19 | 01:09:52:237PM | Plasma | Ok | |
| 20 | 01:26:47:343PM | Plasma | Ok | |
| 21 | 01:42:01:423PM | Plasma | Ok | |
| 22 | 01:59:07:680PM | Plasma | Ok | |
| 23 | 02:16:04:670PM | Plasma | Ok | |
| 24 | 02:33:48:287PM | Plasma | Ok | |
| 25 | 02:50:37:980PM | Plasma | Ok | |
| 26 | 03:08:12:303PM | Plasma | Ok | |
| System Availability | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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