| Miniproposals | ||||||||||
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| Operators | |
| Session leader(s): | Steve Golovato |
| Physics operator(s): | Earl Marmar |
| Engineering operator(s): | Vinny Bertolino |
| Engineering Operator Run Comment |
| Session Leader Plans |
| Physics Operators Plans |
| Session Leader Summaries |
| Entered: Jul 7 2004 03:49:07:993PM |
| Author: To Be Determined |
From: ZENITH::MARMAR Date: 25-JUN-1993 22:41:28 Description: run summary 930625 Run Summary for 930625 Physics op -- Marmar Assistant -- Golovato Goals for the run: 1) Investigate effects of pulsed gas on n_e evolution using B side upper valve (slightly better time response than B top); attempt to fuel to density limit. 2) Evaluate marfe evolution for nearly circular discharges while puffing from the side rather than the top. 3) More ECDC between shots to perturb wall conditioning. 4) Fine tune Argon puff for HIREX. Of the 30 plasma attempts, we had 0 duds, 5 fizzles (Ip<100kA) and 25 "good" shots. Regarding the goals: 1) We definitely were able to demonstrate that the pulsed gas has real effects on the density evolution, at least on some shots. When nel was kept below about 5e19, the plasmas were pretty much disruptive free until we ran out of OH. On shots where we reached 6 or 7 e19, disruptions usually ensued. An exception is shot 26, where we were able to get to 7e19 and sawtoothing continued until 300 msec. Shot 26 is also a good example of the "shark-fin" phenomenon, which occurs between 200 and 300 msec. This shows up on the z-meter and the bolos, and may be due to a broadening of the n_e profile; any relationship to the marfe is at the moment unclear. Shot 8 had no pulsed gas (the hybrid put out the waveform, but it never got to the valve), and the shot had much lower density (3e19), high Mo, and saturated softs. It was also a hot shot (Amanda says 1600 for Te from ECE) was not a particularly non-thermal shot (some hards, but not excessive), and Z_eff was around 3 through the middle of the shot. 2) The marfe evolution appears unaffected both by elongation and by puffing from the side. As we have always seen, it forms near the inner midplane and then moves up. Elongations for most of today's shots were around 1.2, with the exception of the first few before I lowered EF1. 3) We ECDC'd between shots 11 and 12 (in argon), between 16 and 17 (in hydrogen) and between 26 and 27 (in He). Shot 12 pleased John Rice (lots of argon) but was interesting in other ways as well. It had high radiated power (2 pi bolo gave 300 kW), and appeared to be radiation cooling. This should be a good one to look at with the bolometer array. Z_eff was around 3. Shot 17 was made dirty by the H2 ECDC (sometimes you wonder why it's called cleaning), with water being the main suspect on the RGA just before the shot. Z_eff was only about 2 just before it disrupted, but at quite a high density (6e19) and relatively low current (200 kA). Shot 27 showed less wall fueling, so maybe there is still hope for He ECDC as a way of reducing trapped H. On the other hand, we had a fair amount of variability in apparent wall fueling without ECDC. I had intended to ECDC in He between all of the shots after 26, but was foiled by a PLC interlock, probably caused by my own error during the attempt to start ECDC after shot 27. We managed some shots with lots of hard X-rays, 22 and 28 being the best (worst?). As has been noted previously, the evaporated Mo causes an abrupt decrease in the water as seen on the RGA, and the subsequent shots are typically cleaner. We continued to be plagued by the random turn-on time of EF3. In shots with late EF3, there is a tendency toward runaway shots; early EF3 tends to give fizzles. The correlation with current hesitation during the rise was not quite so clear, and bears more looking into. 4) ECDC in argon clearly gives the largest amount in the tokamak shots that we have got so far. Using the B bottom valve, we were able to get reasonable amounts into the plasma, but not nearly so much as on shot 12. The subsequent shots showed that the argon disappears with a 1 or 2 shot e-folding; this is important to remember, since once some argon is introduced, there will be a build up over the next couple of shots if the gas puff is not reduced. ECDC in H2 after shot 16 appeared to rid the machine of essentially all the argon. The main problem during the run was the irreproducibility of the EF3 turn-on. We need either to fix this, or to figure out how to make the first 10 or 20 msec of the discharge robust against EF3 timing changes of up to 3 msec. The only other serious engineering problem we had was the lack of pulsed gas on shot 8. After the shot, we examined the relevant cables between the hybrid and the AFOL; no obvious problem was found and the malfunction did not recur. |
| Physics Operator Summaries |
| Session Leader Comments | |||
| Jun 25 1993 08:54:19:250AM | Steve Golovato | run goals - starting from shot 930619003, push gas to density limit using
b-side-upper gas valve instead of the usual b-top. also see if change in gas puff location affects the marfe we see inside and up. will also do some ecdc between shots and maybe some helium shots. session_leader - marmar assistant - golovato eng op - bertolino | |
| Jun 25 1993 09:15:04:140AM | Steve Golovato | shot 930625001 - same setup as 980619003. prefill gas 4e-5 hydrogen.
ecdc'd for 1.67 hours, turned off at 8:05, first shot at 8:55. very short shot, though not a complete fizzle according to marmar. looked like the last shot of yesterday. went vertically unstable up at 30 ms. | |
| Jun 25 1993 09:15:21:490AM | 930625001 | Steve Golovato | shot 930625001 - same setup as 980619003. prefill gas 4e-5 hydrogen.
ecdc'd for 1.67 hours, turned off at 8:05, first shot at 8:55. very short shot, though not a complete fizzle according to marmar. looked like the last shot of yesterday. went vertically unstable up at 30 ms. |
| Jun 25 1993 09:29:20:380AM | 930625002 | Steve Golovato | shot 930625002 - same setup as shot 001. prefill lowered to 3.7 e-5.
curent pulse in efc just before disruption on shot 001, apparently induced by vertical movement. efc ssupyy was disconnected from coils although all supplies and contollers for efc were already off. ef3 was a little early in shot 001, could have been the problem on shot 001. this one worked, but went unstable up at 175 ms., but had first disruption at 150 ms, may have been density limit. no marfe seen. |
| Jun 25 1993 09:53:10:660AM | 930625003 | Steve Golovato | shot 930625003 - pulse gas lowered early. ground fault current seen in
efc on shot 002, so other side of coils disconnected (only one side had been disconnected at first. plasma elongates starting around 150ms, so ef1 reduced from 3000 to 2000 a at 140ms. good shot but hard x-rays. first disruption at 300ms, lost plasma at 340. |
| Jun 25 1993 10:09:10:530AM | 930625004 | Steve Golovato | shot 930625004 - less elongation on shot 003, 1.4 instead of 1.5.
nl took about twice as long to get to aroung 6e19, 300ms instaed of 150ms. raised pulsed gas back up, both breakdown puff and at 100ms. zeff high on these shots. less hards but disrupted sooner, first around 170 ms. lowered ef1 at 150ms from 2000 to 1500 to lower elongation. density rise faster after second puff, still disrupts at about 6e19. these shots have been sawtoothing. |
| Jun 25 1993 10:09:12:860AM | 930625004 | Steve Golovato | shot 930625004 - less elongation on shot 003, 1.4 instead of 1.5.
nl took about twice as long to get to aroung 6e19, 300ms instaed of 150ms. raised pulsed gas back up, both breakdown puff and at 100ms. zeff high on these shots. less hards but disrupted sooner, first around 170 ms. lowered ef1 at 150ms from 2000 to 1500 to lower elongation. density rise faster after second puff, still disrupts at about 6e19. these shots have been sawtoothing. |
| Jun 25 1993 10:22:18:540AM | 930625005 | Steve Golovato | shot 930625005 - lowered ef1 at 150ms from 2000 to 1500 to lower elongation.
rasied breakdown puff and lowered 100ms puff. first disruption at 160ms, around the same nl. ends earlier, around 230ms |
| Jun 25 1993 10:37:14:950AM | 930625006 | Steve Golovato | shot 930625006 - lowered both puffs but not as much as for shot 003.
trying to control density rise, keep in below apparent limit. also tweaked ef1 a little. slower early density rise, second puff effect seen at 150ms. first disruption at 210ms, lasts to end of magnets around 320ms. kappa lower, peaks about 1.35 at 200 ms. |
| Jun 25 1993 10:49:09:740AM | 930625007 | Steve Golovato | shot 930625007 - raising first puff, lowering second.
ef3 turnon timing shifting around 1ms, affects current rise. get hesitation when turnon early, breaks down inside. better rise when turnon late, breakdown to the outside. nice shot. first disruption at 290ms. marfe starting around 210. sawtoothing throughout. nl rise slower, hangs up 120-180ms, then rises to about 6e19. |
| Jun 25 1993 11:27:13:180AM | 930625008 | Steve Golovato | shot 930625008 - redo last shot. lower density, no pulsed gas.
hards, with big burst at end. lasted to 370ms. cooked limiter at end. no apparent problem with pulsed gas, try again. |
| Jun 25 1993 11:34:04:900AM | 930625009 | Steve Golovato | shot 930625009 - worked. higher moly early. a lot like shot 007.
no argon puff. lasts to 370ms, first disruption at 330, when late puff at 300 ms raises density. |
| Jun 25 1993 11:51:02:750AM | 930625010 | Steve Golovato | shot 930625010 - argon on. higher density. esm says the the walls were
more loaded for 010 than 009 because the pulse dgas worked on 009 and not on 008 (get it?). only lasted to 300ms, first disruption aty 290. |
| Jun 25 1993 12:05:55:440PM | 930625011 | Steve Golovato | shot 930625011 - redo again, then start ecdc between shots.
similar to shot 010, lasted to 340ms, disrupted at 310, nl a little lower. |
| Jun 25 1993 12:05:58:310PM | 930625011 | Steve Golovato | shot 930625011 - redo again, then start ecdc between shots.
similar to shot 010, lasted to 340ms, disrupted at 310, nl a little lower. |
| Jun 25 1993 12:06:00:100PM | 930625011 | Steve Golovato | shot 930625011 - redo again, then start ecdc between shots.
similar to shot 010, lasted to 340ms, disrupted at 310, nl a little lower. |
| Jun 25 1993 12:16:42:620PM | 930625012 | Steve Golovato | shot 930625012 - ecdc for 3 minutes, shut off for high reflected power
fault on magnetron. ecdc was in argon, not hydrogen as is usually done. disrupted at 190ms, lasted to 240ms. softs saturate from argon, more density. zeff about 3. |
| Jun 25 1993 12:33:09:100PM | 930625013 | Steve Golovato | shot 930625013 - fizzled, try again.
maybe very early ef3 turnon. |
| Jun 25 1993 12:48:56:350PM | 930625014 | Steve Golovato | shot 930625014 - ef3 appears to be identical to the previous shot but this
shot worked. density rise a little faster, especially late. rice saw about 1/3 the argon of shot 012. |
| Jun 25 1993 12:48:58:220PM | 930625014 | Steve Golovato | shot 930625014 - ef3 appears to be identical to the previous shot but this
shot worked. density rise a little faster, especially late. rice saw about 1/3 the argon of shot 012. |
| Jun 25 1993 12:57:10:470PM | 930625015 | Steve Golovato | shot 930625015 - raised early gas, lowered late. trying the get
density up quicker to keep moly out and have a flat steady-state at nl0=4.e19, avoid late rise. fizzled. |
| Jun 25 1993 01:16:55:320PM | 930625016 | Steve Golovato | shot 930625016 - raised ef4 from 655a to 675a at t=0- to compensate for
early ef3s. examination of data on ef3 turnon and current rise for shots 1-15 was inconclusive. the variations in ef3 turnon did not show strong patteern for fizzles and good shots or for steady current ramps and hesitations. fizzles only occur for early turnon but at least one shot went with the same early turnon. good shot. first good shot with changed gas. smaller moly peak in softs, density roughly flat from 100-300ms. |
| Jun 25 1993 01:16:57:610PM | 930625016 | Steve Golovato | shot 930625016 - raised ef4 from 655a to 675a at t=0- to compensate for
early ef3s. examination of data on ef3 turnon and current rise for shots 1-15 was inconclusive. the variations in ef3 turnon did not show strong patteern for fizzles and good shots or for steady current ramps and hesitations. fizzles only occur for early turnon but at least one shot went with the same early turnon. good shot. first good shot with changed gas. smaller moly peak in softs, density roughly flat from 100-300ms. |
| Jun 25 1993 01:16:59:010PM | 930625016 | Steve Golovato | shot 930625016 - raised ef4 from 655a to 675a at t=0- to compensate for
early ef3s. examination of data on ef3 turnon and current rise for shots 1-15 was inconclusive. the variations in ef3 turnon did not show strong patteern for fizzles and good shots or for steady current ramps and hesitations. fizzles only occur for early turnon but at least one shot went with the same early turnon. good shot. first good shot with changed gas. smaller moly peak in softs, density roughly flat from 100-300ms. |
| Jun 25 1993 01:17:00:320PM | 930625016 | Steve Golovato | shot 930625016 - raised ef4 from 655a to 675a at t=0- to compensate for
early ef3s. examination of data on ef3 turnon and current rise for shots 1-15 was inconclusive. the variations in ef3 turnon did not show strong patteern for fizzles and good shots or for steady current ramps and hesitations. fizzles only occur for early turnon but at least one shot went with the same early turnon. good shot. first good shot with changed gas. smaller moly peak in softs, density roughly flat from 100-300ms. |
| Jun 25 1993 01:57:34:280PM | 930625017 | Steve Golovato | shot 930625017 - added short puff peaked at 115ms.
cycle hung up, some problem twith shot statistics being entered in logbook. doing some ecdc in hydrogen while trying to fix it, for about 5.25s. long time between shots here. disrupted at 150ms, lost vertically up. walls are very loaded from ecdc. plasma dirty, density up. zeff lower early, less moly because of higher early density. zeff=2 later in spite of high density. |
| Jun 25 1993 02:08:56:980PM | 930625018 | Steve Golovato | shot 930625018 - turned off high puffs at 0 and 115ms, left the lower
maintenance level of pulsed gas. let the walls provide the gas. fizzled. |
| Jun 25 1993 02:25:29:020PM | 930625019 | Steve Golovato | shot 930625019 - try again, lower pre-fill to 3.4e-5 fro, 3.7e-7.
lots of hards, disrupts at 350ms, ends at 380ms. low density. late puff raises density. |
| Jun 25 1993 02:36:11:040PM | 930625020 | Steve Golovato | shot 930625020 - put back puff at 0ms about half as big as before, hopefully
to keep down runaways and maybe avoid current long hesitation in initial current rise seen on last shot. put back puff at 115ms, extended it to 125ms to raise density at about 150ms. fizzled, almost went. |
| Jun 25 1993 02:51:52:430PM | 930625021 | Steve Golovato | Changes for shot 21:
EF4 lowered from 675 to 665 A until t=0 Argon puff width increased from 10 to 12 msec shot went but current had large hesitation. density responded to larger second puff at started disrupting at 190ms, ended at 280ms. |
| Jun 25 1993 03:07:10:390PM | 930625022 | Steve Golovato | Changes for shot 22:
raised first puff, lowered second. lowered prefill to 3.1e-5 from 3.4e-5. mucho sparks, major runaway shot. |
| Jun 25 1993 03:24:15:900PM | 930625023 | Steve Golovato | Changes for shot 23:
raised pre-fill to 4.e-5 and first pulsed gas puff. good shot, first disruption at 340ms, ends at 380. nl flat from 200-300ms at 4-5e19, zeff about 1. |
| Jun 25 1993 03:38:35:920PM | 930625024 | Steve Golovato | Changes for shot 24:
lowered fill to 3.7e-5. increased argon puff by 2ms to 14ms at -100ms. moly early, disrupts at 230ms, ends at 340ms. record peak current at 370ka. argon may have affected shot, zeff higher. |
| Jun 25 1993 03:49:09:910PM | 930625025 | Steve Golovato | Changes for shot 25:
reduce argon puff back to 12ms. another record current, 385ka. nice shot doesn;t disrupt until 340ms, ends at 380ms. still a lot of moly early. flat nl from 200-340ms. zeff a little over 1. |
| Jun 25 1993 04:10:55:270PM | 930625026 | Steve Golovato | Changes for shot 26:
try to increase density at around 150ms. increase puff at 100ms. slower current ramp but no hesitation, lower current. less moly early. disrupted at 300ms. density lower up to 100ms, puff brings nl up to 7e19 without disrupting. central nl flat from 200-300ms, but edge nl, bolo, softs jump up over this time. density profile apparently broadens. |
| Jun 25 1993 04:32:08:170PM | 930625027 | Steve Golovato | Changes for shot 27:
ecdc in helium between 26 and 27 for 7 minutes. lower density, higher current. helium ecdc may have depleted walls. puff at 100ms raises nl from 2.2 to 4.4e19 between 10-200ms. apparent impurity "event" at .12s on softs and bolo. |
| Jun 25 1993 04:41:24:780PM | 930625028 | Steve Golovato | Changes for shot 28:
no ecdc before this shot because of pcl problem. runaway shot. helium must have depleted walls. moly gettering occurs on these shots, need to increase gas. pcl problem continues. |
| Jun 25 1993 04:54:00:610PM | 930625029 | Steve Golovato | Changes for shot 29:
increase pre-fill to 4.e-5 and first puff by broadening it by a few ms. good shot. some hard x-rays. nl reaches a nice steady-state at 5.e19. disrupts at late puff at 350ms. |
| Jun 25 1993 05:09:23:870PM | 930625030 | Steve Golovato | Changes for shot 30:
increase puff at 100ms. hards pretty high. fill was actually a little low, 3.7, not 4. very similar to last shot. hypotheseis about runaway generation: if ef3 comes on late, get more runaways, as on shots 28-30. early can be before t=0, late can be t=2.5ms. |
| Physics Operator Comments |
| Engineering Operator Comments | ||||
| Shot | Time | Type | Status | Comment |
| 1 | 08:52:52:430AM | Plasma | Ok | fizzle -- no faults |
| 2 | 09:18:20:470AM | Plasma | Ok | efc discon |
| 3 | 09:35:33:440AM | Plasma | Ok | efc tmx isolatedf |
| 4 | 09:59:52:350AM | Plasma | Ok | 320ka plasma |
| 5 | 10:12:37:220AM | Plasma | Ok | 230ka plasma -- no faults |
| 6 | 10:26:55:730AM | Plasma | Ok | 310ka plasma -- no faults |
| 7 | 10:40:33:920AM | Plasma | Ok | 280ka plasma -- no faults |
| 8 | 10:55:57:080AM | Plasma | Ok | 310ka plasma -- no faults |
| 9 | 11:22:37:240AM | Plasma | Ok | 320ka plasma -- no faults |
| 10 | 11:35:46:560AM | Plasma | Ok | 240ka plasma -- no faults |
| 11 | 11:50:00:130AM | Plasma | Ok | 270ka plasma -- ecdc for 5min |
| 12 | 12:07:53:700PM | Plasma | Ok | silva in charge |
| 13 | 12:20:08:950PM | Plasma | Ok | fizzle |
| 14 | 12:35:48:190PM | Plasma | Ok | vinnies back |
| 15 | 12:51:46:490PM | Plasma | Ok | fizzle |
| 16 | 01:06:36:980PM | Plasma | Ok | 290ka plasma -- no faults |
| 17 | 01:47:47:450PM | Plasma | Ok | no faults -- 240ka plasma |
| 18 | 02:02:00:880PM | Plasma | Ok | fizzle |
| 19 | 02:13:55:980PM | Plasma | Ok | 300ka plasma -- no faults |
| 20 | 02:28:05:600PM | Plasma | Ok | fizzle |
| 21 | 02:41:11:300PM | Plasma | Ok | 300ka plasma -- no faults |
| 22 | 02:58:09:540PM | Plasma | Ok | 330ka plasma -- no faults |
| 23 | 03:10:53:980PM | Plasma | Ok | 310ka plasma -- no faults |
| 24 | 03:26:57:800PM | Plasma | Ok | 370ka plasma -- no faults |
| 25 | 03:41:01:970PM | Plasma | Ok | 380ka plasma -- no faults |
| 26 | 03:56:06:450PM | Plasma | Ok | 300ka plasma -- nofaults, ecdc before ne |
| 27 | 04:15:13:190PM | Plasma | Ok | 310ka plasma |
| 28 | 04:33:43:670PM | Plasma | Ok | 330ka plasma -- no faults |
| 29 | 04:45:53:300PM | Plasma | Ok | 350ka plasma |
| 30 | 04:58:08:540PM | Plasma | Ok | 320ka plasma -- no faults |