| Miniproposals | ||||||||||
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| Operators | |
| Session leader(s): | Steve Golovato |
| Physics operator(s): | Steve Horne |
| Engineering operator(s): | Vinny Bertolino,Joe Daigle |
| Engineering Operator Run Comment |
| icrf heating |
| Session Leader Plans |
| Physics Operators Plans |
| Session Leader Summaries |
| Entered: Jul 7 2004 03:49:11:740PM |
| Author: To Be Determined |
| run summary - 941222 --------------------- SL: golovato PO: horne EO: bertolino/daigle Goals- Tune E-port antenna at high density (where we can get match easier) and increase power, condition antenna. Bring up D-port to high power simultaneously, get as much total power as possible. Compare performance of the two antennas, look for any interactions between them. We accomplished some of the above goals but were hampered by two problems with the rf systems. First, the E-port tuners are slightly less than one half wavelength, leaving a gap in the tuning ranges. This is a particular problem for the stub, whose admittance goes like the cotangent of its length. Most of the variation of the impedance occurs over a short length near half wavelength intervals. As luck would have it, that's where our gap is. We will fix this by adding a short length of coax to the stub (in fact it has already been done) allowing us to tune to good matches over a wider range of plasmas. For this run we chose high density plasmas and/or small outer gaps to get the high loading we needed to get adequate, but not great, matches. The second problem was that transmitter 2, which powers the E-port antenna, was crowbarring every shot. The power is supposed to interrupt and retry rather than trip the power supply. The retries provide conditioning of the antenna, the lack of them slows down the process. Crowbarring is also bad for the tube and power supply. Nevertheless, we made some progress during the run. We strarted with a slot divertor plasma, shot 941220020, at high density (nl_04=1.5e20). Horne adjusted this plasma to have the standard divertor strike points to keep it off the inner nose. We tried this for the first 11 shots. We had trouble getting power up on E-port and thought high gas puffing required to hold the density might be affecting the power handling. So we switched to another configuration, shot 941216024, which was inner wall limited, had a 0.5 cm outer gap, but more modest nl=1.e20. It took several shots to make the switch. We increased the outer gap to 1cm and it worked from then on. We ran the antennas at different times, E from .35 to .8 sec and D from .8 to 1 sec unitl shot 30, where we started to try overlapping the pulses. D port ran reliably at 1.7-1.8 MW and even ran at 2 MW for 50ms on shot 28. At the highest power, the transmitter was tripping from screen overcurrent, the usual limation at high power. Te and Ti were doubled simultaneously with a 30 kJ increase in stored energy, on shot 22 for example. E port was more erratic but did get up to high power on the last few shots. The best shot was the last, where D and E overlapped for 60 ms and reached 2.7MW of total input rf power with over 1 MW from E-port. We have some problems with the plasma apparently striking the E-port antenna protection tiles (on the F-port side) near the midplane, causing them to glow noticably every shot. We tried hard to maintain the outer gap, particularly during crossover, to eliminate this but were only successful in reducing the effect. This may play some role in limiting the power to E-port thus far. Lithium pellets were also applied during the run, medium pellets on shots 23 and 32 and small pellets on shots 24-30. They were all fired at 450ms, before the rf. There were apparently some interesting and new effects seen. Snakes were generated, even with the small pellets, indicating penetration to q=1. The session leader shot-to-shot summary can be found in the logbook under the session_leader topic. The shot summary was: 31 plasmas (3 disrupted very early) 2 fizzles Thanks to the engineering group for giving us the last shot after 5:00pm to finish out the year in style with a record total rf power. Happy Holidays!!! |
| Physics Operator Summaries |
| Entered: Jul 7 2004 04:36:52:583PM |
| Author: To Be Determined |
run 941222 Golovato, Horne Rf run. Loaded shot set up for slot divertors, includes reference switch on segment 2. Plan to work on rampdown as piggyback. Try to develop a strategy based on zero drawn IP, very low gain on IP. If gain is constant, should get exponential rampdown. Consider gain steps. From wirehead point of view, run has two parts. Shots 1-11 were diverted. 12-33 limited. EF1 L had relatively consistent problems in inversion. Segment 1 programming was adjusted to match up the ef1 currents across the joint. Some shots had imbalanced ef1 currents at breakdown but there was only one fizzle today (shot 5). The diverted shots had rampdown problems, possibly due to the rather high programmed density; more likely due to the loss of control of the EF2 coils when their current goes to zero. I tried 3-segment operation on shot 4 but had not properly programmed it. The E-port antenna was apparently unhappy with these plasmas so we switched to a diverted plasma on shot 12. This was successful after a couple of tweaks. Starting shot 19 I tried the 3'rd segment again, programmed properly this time. Over the next several shots evolved to a ramp-down sequence with zero drawn IP -- object was to make a sequence which could be switched in at any time, independent of plasma current. This seemed to work -- shots 23-29 and 33 had this programming. For 31 and 32, switch back to 2-segment operation, using 1 and 3. This worked. I think we've verified PCS operation in nearly all of the more exotic configurations; since we are running 3 segments, Josh says he will create segment 4 for our startup next year. Steve G and Yuichi will post an RF report; the bottom line is 2.8 MW on shot 33. (for rather short time -- dt or so). Scorecard -- 32 plasmas, one fizzle. Shot log: 1 load 941220020. Copy segment 2 to segment 3. Set segment 3 start time to 1.25 sec, not on yet though. Reduce strike_psi proportional gain to .8, integral gain off (no reset). Nasty shot. 2 Reduce programmed density. Fizzle detector to 1.6 Good shot. 3 increase density. x-point isn't perfect -- inner strike point is on the nose. Fix next shot. Died early -- too much gas? No -- EF1L breaker pulled out. 4 strike_psi gain reduced to .5, programmed to -.001 (was -.003) Increase density to 1.5e20 Turn on segnment 3!!. Plasma exploded at the segment switch. EF1 L breaker. 5 Turn off segment switch. I had not corrected segment 3 to match segment 2 -- that may have been responsible for the disruption. Other possibility is bug w 3 segments. Raise density earlier. Raise zxl and rxl gain, remove gain notch from zxl Plasma fizzled. EF1 L breaker again. It's pulling out in inversion; so backing off it's gain shouldn't affect the startup much (I hope). Scatterplot shows br is terrible. I've no idea why it's worked at all. 6 repeat Plasma. TV shows disruption. We loose plasma when ef2 coils go to zero current. EF1L power supply gain has changed. 7 Repeat, plasma disrupted just after segment switch due to EF1 L pulling out. 8 change ef1 segment 1 programming to match up better to segment 2. want's to be -3000 , was -2000, make it -2500. Plasma ran. Disruption on rampdown at .25 MA. 9. Increase integral gain on ef1l only in segment 1 from 3 to 4. Plasma. We loose it when ef2 currents go to zero. Try moving x-points to larger radius. Should try lowering zxl a half cm or so -- elongation isn't too high so we should be able to stand it. 10 Plasma. Still trouble with ef2 Drop zxl to -.001 for next shot. 11 Init failure, try again... Plasma. 12 RF wants a limited plasma now. Try getting it by adjusting programmed waveforms and gains, so we keep segment 2 reference switch. Cut in rcur, zcur, clearin, xpoint locations from pcs s scope shot 941216024 strike point gain to zero. nl_04 programmed to 1.e20. Fizzle. Possibly ef1 imbalance again, or dirty -- CII light high. Try ef1l integral gain to 4.5 13 short, dirty, disruptive, nasty, foul,... Just load the shot. 14 Plasma, came to a bad end. 800 ka disruption. Rice claims credit. We deleted his second and third puff. efit looks good. Startup is different from shot 941216024 ; ef1L in particular. 15 Better but not good. Rice now claims that RF tossed moly into plasma. Adjust ef1 currents in segment 1 to match across the segment jump. reduce rcur at end of shot from .666 to .663 to increase outer gap. rcur=number_of_beast might be cause of disruption. Especially since it's so close to Christmas. 16 Much nicer shot, rampdown to < 70 kA. Program lower xpoint a bit lower during rampdown. 17 Like last shot. Small tweak to clearin and rcur late. 18 Nominal. Add segment 3 at 1.4 sec (copy of segment 2) Change zxl programming early to prevent "accidental" diversion. 19 Nice shot. No sign of glitch at segment switch. segment 3 start at 1.3 aout error changes by 40000 at rampdown. This x pid p gain of 3.6 = nice rampdown. Draw IP in segment 3 to zero; set PID gain to 40/200 * 3.6 = 150/200 = 1. Try 1.6 or it will take forever. 20 Nice plasma, rampdown in segment 3 worked !! Try moving segment 3 to 1.2 sec. Error will go from 300kA to 500kA. Nice rampdown again. We seem to be able to tolerate this, but the PID output changes by 1 V, compared to .25 volts during our usual rampdown. Set start time at 1.1; error goes to 700 ka. Reduc gain to .5 there, and step it up later. Between .250 and .4-.45 or so, as plasma recovers from crossover, it is bumping the antenna. You can see the antenna glow. Program rcur in by 1/2 cm during this period. 21 Nice again. The gain changes in IP in segment 3 result in an almost linear rampdown. Try switch at 1.0. "Medium" Lithium pellet at .45 sec 22 No problems. Pellet causes small glitch in plasma current. Discovered that current in segment 3 wasn't properly drawn to zero. Went to zero at 1.2 sec. Draw to zero for next shot. want 40 / 800 * 3.6 =160/800 = .2 Set .3 23 Worked fine. 24 No change, no problem. Plasma still gently kissing e-port limiter. 25 Tweak rcur another 2 mm in as in shot 20. Plasma. 26 Hard x-rays creeping up early. Raise fill to 1.6, program density up a little faster. Lithium Pellets still going in at .45 Plasma. still touching antenna at .2 or so. Adjust clearin gain early. 27 Plasma No pellet this time. 28 Pellet back on. Fiddle with rcur. Good shot, outer gap seems better controlled. 29 no change. Good shot. Bright spot still there. Boring. For excitement, try running segments 1 and 3. Copy segment 2 to 3. New rampdown scenario can be recovered from segment 3, this shot. (29) 30 Good shot. Segments 1 and 3 did right thing, apparently. 31 No change. Good shot. 32 Prepare to put my rampdown back, but don't load it yet. Good shot. 33 Load the rampdown. Good shot; rampdown worked. |
| Session Leader Comments | |||
| Dec 22 1994 08:53:50:640AM | Steve Golovato | run 941222 - last run of 1994
Goals- tun eE-port antenna at high density (where we can get match easier, and increase power, condition antenna. Bring up D-port to high power simultaneously, get as much total power as possible. Compare performance of the two antennas, look for any interactions between them. | |
| Dec 22 1994 08:56:45:190AM | Steve Golovato | run 941222 - last run of 1994
Goals- Tune E-port antenna at high density (where we can get match easier) and increase power, condition antenna. Bring up D-port to high power simultaneously, get as much total power as possible. Compare performance of the two antennas, look for any interactions between them. | |
| Dec 22 1994 08:59:49:480AM | 941222001 | Steve Golovato | 941222001 - loading 941219020 which matched antenna well, had slot
divetor and good rampdown, nl programmed to 1.5e20. tweaked a little to move x-point away from nose. early disruption, too much gas too soon for first shot. |
| Dec 22 1994 09:01:46:590AM | 941222002 | Steve Golovato | 941222002 - good shot, density lowered both early and late.
no rf data, mistuned anyway since density lower than we tuned to, |
| Dec 22 1994 09:06:15:060AM | 941222003 | Steve Golovato | 941222003 - good shot, but disrupted at 850ms. programmed at 1.2e20.
lost ef1-l at 800ms. both antennas reasonably well matched. |
| Dec 22 1994 09:10:23:860AM | 941222003 | Steve Golovato | 941222003 - good shot, but disrupted at 850ms. programmed at 1.2e20.
lost ef1-l at 800ms. both antennas reasonably well matched. |
| Dec 22 1994 09:31:03:900AM | 941222004 | Steve Golovato | 941222004 - raised density programming to 1.5e20. good shot,density
reaches programmed value. 1.2MW on D-port, tuning not bad but needs tweaking. |
| Dec 22 1994 09:30:40:600AM | 941222005 | Steve Golovato | 941222004 - raised density programming to 1.5e20. good shot,density
reaches programmed value. 1.2MW on D-port, tuning not bad but needs tweaking. |
| Dec 22 1994 09:35:15:400AM | 941222005 | Steve Golovato | 941222005 - brought denity earlier, raised powerand tuned D-port,
separated D and E port pulses in time. D at 0.825-1.sec, E at .350-.825 sec. fizzle and ef1 power supply tripping out, to be adjusted. |
| Dec 22 1994 10:01:37:010AM | 941222006 | Steve Golovato | 941222006 - good shot, density came up slowly. no efit data for
som ereason. D-port interrupting, tuning bad. |
| Dec 22 1994 10:14:40:580AM | 941222007 | Steve Golovato | 941222007 - early disruption, like shot 1. ef1 behaving differently
from shot 941220020. |
| Dec 22 1994 10:27:06:940AM | 941222008 | Steve Golovato | 941222008 - good shot. 1.2MW. E-port crowbarring. density looks good.
heating with D-port looks good. |
| Dec 22 1994 11:01:42:390AM | 941222010 | Steve Golovato | 941222010 - density gets up to 15e20 quicker, not like last shot
although nothing was changed. 1.3MW on D. |
| Dec 22 1994 11:10:24:700AM | 941222010 | Steve Golovato | 941222010 - density gets up to 15e20 quicker, not like last shot
although nothing was changed. 1.3MW on D. |
| Dec 22 1994 11:34:41:650AM | 941222011 | Steve Golovato | 941222011 - good shot, 1.45MW on D. E tripping at lower and lower power
maybe high gas load at high density makes it difficult to run it. E port ran better on 941216 with innner wall limited plasmas centerred in z with a 1 cm outer gap. |
| Dec 22 1994 11:36:31:860AM | 941222012 | Steve Golovato | 941222012 - fizzle.
|
| Dec 22 1994 11:51:33:670AM | 941222013 | Steve Golovato | 941222013 - early disruption.
|
| Dec 22 1994 12:08:25:750PM | 941222014 | Steve Golovato | 941222014 - reloaded shot 941216024 entirely, not just some traces.
disrupted at 830ms. E port ran well, match not bad. Disrupted before D port pulse. |
| Dec 22 1994 12:28:03:480PM | 941222015 | Steve Golovato | 941222015- same shot, same disruption. E-port to .5 MW, no D-port rf.
try increasing outer gap from .5 to 1 cm.. |
| Dec 22 1994 12:47:20:960PM | 941222016 | Steve Golovato | 941222016 - good shot, .6 kw on E, 2 MW on D.
|
| Dec 22 1994 12:55:57:830PM | 941222017 | Steve Golovato | 941222017 - 1.8MW on D, .5MW on E, crowbars each shot. outer gap grows
starting at 850ms. extend clearin and rcur programming out to 950ms from 850ms for next shot. |
| Dec 22 1994 01:18:13:110PM | 941222018 | Steve Golovato | 941222018 - good shot, D port interrupting with plasma held at 1cm,
needs to be tuned. E port crowbars at 600kw. |
| Dec 22 1994 01:31:57:660PM | 941222019 | Steve Golovato | 941222019 - D-port at 1.3MW. E-port crowbars early when plasma is on
outer limiter. |
| Dec 22 1994 01:56:12:320PM | 941222020 | Steve Golovato | 941222020 - good shot, E still crowbars.
|
| Dec 22 1994 01:58:12:030PM | 941222021 | Steve Golovato | 941222021 - good shot. plasma moves out to outer limiter between
300-450ms during crossover and final current rise, cuases heating of antenna tiles on E-port. this may limit powere. we ill try to eliminate this excursion. |
| Dec 22 1994 02:24:04:820PM | 941222022 | Steve Golovato | 941222022 - good shot. add Li pellet at 450ms on next shot.
|
| Dec 22 1994 02:25:47:870PM | 941222022 | Steve Golovato | 941222022 - heating very good. del(Ti)=1200eV to 2300eV,
del(Te)=1800eV to 3800eV. del(Wp)=30kJ. |
| Dec 22 1994 02:45:05:730PM | 941222023 | Steve Golovato | 941222023 - 1.7MW on D, short E pulse. Li pellet at 450ms.
|
| Dec 22 1994 02:56:35:540PM | 941222024 | Steve Golovato | 941222024 - 1.8MW on D, .65 on E. Plasma still hitting E-port limiter,
moving plasma in another 5mm 200-450ms. |
| Dec 22 1994 03:25:18:260PM | 941222026 | Steve Golovato | 941222026 - still problems with E-port crowbar. turning off Li pellet
for next shot. |
| Dec 22 1994 03:40:52:970PM | 941222027 | Steve Golovato | 941222027 - good shot. no Li pellet.
|
| Dec 22 1994 03:55:33:800PM | 941222028 | Steve Golovato | 941222028 - 2MW on D for 75ms, then transmitter tripped.
|
| Dec 22 1994 03:56:17:890PM | 941222028 | Steve Golovato | 941222028 - Li pellet back on.
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| Dec 22 1994 04:18:23:730PM | 941222029 | Steve Golovato | 941222029 - try overlapping D and E on next shot.
|
| Dec 22 1994 04:23:43:270PM | 941222030 | Steve Golovato | 941222030 - D-port tripped when E went on, screen current trip.
|
| Dec 22 1994 04:42:43:710PM | 941222031 | Steve Golovato | 941222031 - both ran together for about 8ms at 2.5MW total power.
then E-port tripped followed by D port. |
| Dec 22 1994 04:50:35:470PM | 941222032 | Steve Golovato | 941222032- medium Li pellet this shot. both tripped as usual.
|
| Dec 22 1994 05:20:13:310PM | 941222033 | Steve Golovato | 941222033- no Li pellet. 50ms overlap getsa to 2.8MW total.
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| Physics Operator Comments |
| Engineering Operator Comments | ||||
| Shot | Time | Type | Status | Comment |
| 1 | 08:33:04:280AM | Plasma | Ok | no faults |
| 2 | 08:45:00:390AM | Plasma | Ok | no faults |
| 3 | 08:58:14:460AM | Plasma | Bad | ef1l comm fault |
| 4 | 09:12:11:930AM | Plasma | Ok | disruption induced comm faults ef1l, oh1 |
| 5 | 09:27:16:850AM | Plasma | Ok | fizzle |
| 6 | 09:41:18:650AM | Plasma | Ok | no faults |
| 7 | 09:57:22:890AM | Plasma | Bad | ef1l failed at segment change in hybrid program |
| 8 | 10:18:23:060AM | Plasma | Ok | no faults |
| 9 | 10:36:24:990AM | Plasma | Ok | no faults |
| 10 | 10:50:53:550AM | Plasma | Ok | no faults |
| 11 | 11:05:18:580AM | Plasma | Ok | no faults |
| 12 | 11:34:09:910AM | Plasma | Ok | no faults |
| 13 | 11:48:10:130AM | Plasma | Ok | no faults |
| 14 | 12:00:40:740PM | Plasma | Ok | no faults |
| 15 | 12:12:58:300PM | Plasma | Ok | no faults |
| 16 | 12:29:28:490PM | Plasma | Ok | no faults |
| 17 | 12:44:17:220PM | Plasma | Ok | No faults. |
| 18 | 12:58:28:590PM | Plasma | Ok | no faults plasma no disruption |
| 19 | 01:13:20:120PM | Plasma | Ok | No Faults |
| 20 | 01:28:08:510PM | Plasma | Ok | No Faults |
| 21 | 01:41:32:020PM | Plasma | Ok | No Faults. |
| 22 | 02:02:24:470PM | Plasma | Ok | No faults. |
| 23 | 02:22:19:300PM | Plasma | Ok | No Faults. |
| 24 | 02:39:46:260PM | Plasma | Ok | No faults. |
| 25 | 02:57:02:770PM | Plasma | Ok | No Faults |
| 26 | 03:13:32:870PM | Plasma | Ok | No Faults. |
| 27 | 03:30:01:290PM | Plasma | Ok | No faults. |
| 28 | 03:44:37:070PM | Plasma | Ok | No Faults. |
| 29 | 03:58:21:470PM | Plasma | Ok | No Faults |
| 30 | 04:13:57:100PM | Plasma | Ok | No Faults. |
| 31 | 04:29:45:150PM | Plasma | Ok | No Faults. |
| 32 | 04:44:08:750PM | Plasma | Ok | No Faults. |
| 33 | 05:02:07:590PM | Plasma | Ok | NO faults. |