| Miniproposals | ||||||||||
| ||||||||||
|
| Operators | |
| Session leader(s): | Ian Hutchinson,Joseph Snipes |
| Physics operator(s): | Steve Wolfe |
| Engineering operator(s): | Vinny Bertolino,Joe Daigle |
| Engineering Operator Run Comment |
| reveresed field (normal) |
| Session Leader Plans |
| Physics Operators Plans |
| Session Leader Summaries |
| Entered: Jul 7 2004 03:49:13:100PM |
| Author: To Be Determined |
| 10 shots for MP094 Low q H-mode Run with Ion Grad B Drift away from X point Engineer in Charge: Joe Daigle Physics Operator: Steve Wolfe Session Leader: Joe Snipes While the power supplies and the rest of the machine ran well, there were problems getting the current to rise with the reversed field. Finally, by shot 30, we got a decent plasma. The density was varied from about 6 x 10^19 m^-2 to 9 x 10^19 m^-2. No H-modes were observed even though the P/(nBS) values exceeded 0.04 or even 0.05. So, it appears that the threshold is higher with the ion grad B drift away from the X point. It remains to flip the X point up and see if we can get H-modes. Shotlist 30 Ip=0.64 MA, nel=5.7 x 10^19 m^-2. No H-mode 31 Ip=0.64 MA, nel=6.5 x 10^19 m^-2. No H-mode 32 Disrupted at 0.16 sec 33 Disrupted at 0.3 sec 34 Ip=0.7 MA, No H-mode. P/(nBS)=0.03. 35 Ip=0.85 MA. No H-mode. P/(nBS)=0.04 36 nel=7.5 x 10^19 m^-2. P/(nBS)=0.04. No H-mode 37 Ip=0.95 MA. P/(nBS) between 0.04 and 0.05. No H-mode 38 nel = 6 x 10^19 m^-2. No H-mode 39 nel = 9 x 10^19 m^-2. P/(nBS) = 0.044. No H-mode |
| Physics Operator Summaries |
| Entered: Jul 7 2004 04:36:53:740PM |
| Author: To Be Determined |
| Physics Operator Summary for 950404 MP#027 Reverse field startup MP#094 Reverse field low-q ohmic H-mode SL: Hutch & Snipes PO: Wolfe EO: Bertolino,Daigle The first task was to get a good startup with reverse field. We chose to make our task that much harder by looking for a low-field startup, so we could run this low-q run. After a lot of struggling, we succeeded. For a record of the struggles, see the LOGBOOK under PHYSICS_OPERATOR. It is recommended that the startup from shot #29 on be used for all subsequent reverse-field runs. See procedure for running old segment 2's below. Shots 30-39 were devoted to MP#094, a search for ohmic H-modes with low-q, low-field. The starting shot was based on 950214014, modified as described below. All startups were successful, but we had some unexplained disruptions on #32 and 33 (before flattop), 36 and 37 (beginning of rampdown), and 38 (.7 sec). #36 and 37 may have been due to OH1 hitting its current rail at 20kA. The problem on #38 is unexplained; the OH1 limit was moved out to 25kA for 38 and 39, which ran ok. Some of these also had EF1U on its voltage rail. The main parameters on the physics shots were: Shot# Ip (Prog) Ip(actual) NL_04 Comments ---- -------- --------- ----- ________ 29 680kA 630 6e19 30 " " " Add EF2_by_EF4 control 31 " " 7e19 Increase CLEARIN 32 750 -- " Disrupted early 33 " -- " " 34 " 700 " Slow NL and CLEARIN ramps 35 900 850 " 36 " " " Reduce NL gain from 8->4 37 1MA 950 " Disrupted at 1.03 38 " " 6e19 Raise OH1 limit. Disr. @0.7sec 39 " " 1.e20 Ran ok. As can be seen from the above table, the current offset is still there, and for this polarity results in getting less Ip than programmed, instead of more. This should probably be dealt with by an offset in the predictor screen, but one can also adjust what is drawn. The Z-meter indicated higer than normal Zeff today, and Irby noted that the Argon level is about 20 times higher than normal (Rayleigh calibration on Saturday.) The first shots that made it past 100msec looked horribly dirty and disruptive. Granetz's check_magnetics routine was reporting no signal on F14 for much of the morning; this was apparently due to a bad low order bit on the digitizer. Operation at q_psi down to 2.5 was accomplished, although all of the 950kA shots except 39 disrupted (halo warnings). Recommended procedure for running with reverse field: ----------------------------------------------------- Ask for engineering setup (timings, comm. resistors) as on 950404, but with the TF current from the run you want (normal 5.3 Tesla operation is 156kA). Use a Segment 1 from after shot 950404029. This should work ok with the field ramping past. Load the segment 2 you want; if this was from normal field operation, make the following changes: 1) Bring up the ALL_P screen and use "FLIP" (under right mouse button) to invert Ip and all coil current waveforms in use, typically IC_EF4 and EF2_by_EF4. If you aren't using EF2_by_EF4 you probably should modify your programming to do so. See Ian's report from 950331. 2) Bring up the V screen and use "FLIP" to invert all the power supply voltages: OH1, CHOPPER, OH2U, OH2L, EF1U, EF1L, EF2U, EF2L, EF4, EF3. Do not get carried away and invert the pulsed gas. 3) Bring up the RCUR screen and change the offset from 8000 to 1000. If you find that the offset was not 8000, you probably have an obsolete predictor. In that case, use the "CALL" button to recalculate the predictor, and then put 1000. in the offset field. You may need to reduce the FACTOR a small amount as well. If the RCUR predictor was bad, you probably should recalculate all the magnetics predictors, as they are probably out of date as well. Note that this has nothing to do with reverse field per se. 4) Note that the current you get is going to be less than what you drew by about 50kA. To correct this, either re-draw the waveform, or add an offset to the Ip. I think you want to put in +50000, but I may have the sign wrong. 5) Load and go. Scorecard: ---------- Tests 1 Duds 1 Fizzles 21 Plasmas 16 (> 50kA) ------- -- Shots 39 |
| Session Leader Comments | |||
| Apr 4 1995 02:53:05:090PM | 950404030 | Joseph Snipes | Shot 30
Good shot. Ip = 0.7 MA and BT = 3.55 T, nel = 5.7 x 10^19 m^-2. No H-mode. |
| Apr 4 1995 03:08:29:790PM | 950404031 | Joseph Snipes | Shot 31
Good shot. Ip = 0.64 MA and BT = 3.55 T, nel = 6.5 x 10^19 m^-2. No H-mode. |
| Apr 4 1995 03:31:28:910PM | 950404032 | Joseph Snipes | Shot 32
Disrupts at 0.16 sec. |
| Apr 4 1995 03:31:50:650PM | 950404032 | Joseph Snipes | Shot 33
Disrupts at 0.3 sec. |
| Apr 4 1995 04:08:11:300PM | 950404034 | Joseph Snipes | Shot 34
Ip = 0.7 MA. Good shot. No H-mode. P/(nBS) = 0.03. |
| Apr 4 1995 04:12:01:500PM | 950404035 | Joseph Snipes | Shot 35
Ip = 0.85 MA. Good shot. No H-mode. P/(nBS) = 0.04. |
| Apr 4 1995 04:23:28:070PM | 950404036 | Joseph Snipes | Shot 36
Repeat. Ip = 0.85 MA. Good shot. No H-mode. P/(nBS) = 0.04. |
| Apr 4 1995 04:37:51:510PM | 950404036 | Joseph Snipes | Shot 37
Ip = 0.95 MA. Good shot. No H-mode. P/(nBS) between 0.04 and 0.05. |
| Apr 4 1995 04:45:18:700PM | 950404037 | Joseph Snipes | Shot 37
Ip = 0.95 MA. Good shot. No H-mode. P/(nBS) between 0.04 and 0.05. |
| Apr 4 1995 04:49:29:050PM | 950404038 | Joseph Snipes | Shot 38
Ip = 0.95 MA. Disrupted at 0.7 sec. No H-mode. P/(nBS) between 0.05 and 0.06 before the disruption. |
| Apr 4 1995 05:10:45:810PM | 950404039 | Joseph Snipes | Shot 39
nel set to 0.9 x 10^20 m^-2. Ip = 0.95 MA. Good shot. P/(nBS) = 0.044 but no H-mode. Threshold appears to be higher for the grad B drift away from the X point. |
| Physics Operator Comments | |||
| Apr 4 1995 07:23:38:380AM | Steve Wolfe | Run Plan for 950404
First day with reverse field MP 027 (Reverse field startup) and {MP 094 Low q H-mode or MP 107 Reverse field SOL } SL: Hutch & {Snipes or LaBombard} PO: Wolfe (all day) Engineering set up from 950214014: Note that this involves a non-standard OH2 comm. resistor and Strange TF current limit and start time. A-side plenum at 19psi D2 Pre-run ECDC in D2 | |
| Apr 4 1995 07:23:56:390AM | Steve Wolfe | 1A. We'll start from 950214014, a low-q, low-field 700kA shot, with waveforms
suitably flipped for reverse field operation. The first task will be to get a successful startup at the low Bt. We will limit our pain in this attempt to 15 shots or 12 noon, whichever comes first. The remainder of the run will depend on whether we accomplish this goal. If we do, proceed to 2A; if not, go to plan 1B, below. 2A. Assuming success on 1A, start with a 700kA discharge with density ramping down from NL_04=7e19 to < 5e19. Set up the EF2_by_EF4 control to help on the disruption problem that plagued the 2/14 run. 3A. If no H-modes are obtained, increase current to 0.85MA to increase ohmic power. Continue to increase current as long as it looks safe from the disruption point of view, until we either find the ohmic H-mode threshold or set an upper limit. | |
| Apr 4 1995 07:24:39:010AM | Steve Wolfe | 1B. If low-field startup doesn't work, punt this and go back to a standard
5.3T startup, suitably flipped. Use setup from Friday, 950331027. Struggle with this until it works. 2B. Once successful startup has been achieved, start the MP#107 program in the time remaining, if any. Tune up an 800kA shot with density ramp from NL_04=.5e20 to .9e20, using FSP target control and EF2_by_EF4 control; a possible Segment 2 starting point is 950329015, with EF2_by_EF4 control added. 3B. Repeat for higher density ramp (NL_04 from 0.8 : 1.5e20) 4B. repeat for highest density ramp (NL_04 from 1.3 : 2.5e20 ? ) | |
| Apr 4 1995 07:29:22:830AM | Steve Wolfe | Start with prepared shot pcs$wolfe:050404901.
Import seg 3 from seg 2 of 950331027, to get the EF2_by_Ef4 program on-screen Flip traces in seg3 and seg4. In seg1, changed wires 4,5,6,8 to unused; set ref5-8 to "10" Set Fizzle detector on/off to 0.08, 1.6 Load_into_model @4-Apr-1995 07:16:40.00 Do coldstart 07:20 | |
| Apr 4 1995 08:46:52:880AM | 950404001 | Steve Wolfe | Shot #950404001
--------------- First try for plasma. Dud. We've got a big vertical field and a bug radial field. COuld one of the coils not have been reversed? I also get an error on F14 (no finite signal)! It may be ok? Looks like about a +.002 Br and a -.019 Bz. If it's right, I need big adjustments. |
| Apr 4 1995 09:11:45:010AM | 950404002 | Steve Wolfe | Shot #950404002
--------------- Make Br more negative by 3mT (.0065 to .0035) Make IC_EF4 more positive by 150Amps (1180 to 1330) Fizzle, very late breakdown, around 20msec. Got the message on F14 again, I think we're in trouble. Null looks better. Still a bit of Br, and the negative vertical field isn't coming in early enough. |
| Apr 4 1995 09:48:37:420AM | 950404004 | Steve Wolfe | Shot #950404004
--------------- Ef3 only test to see if F14 is working or not Its ok, just a bad low order bit on the digitizer. |
| Apr 4 1995 09:49:34:210AM | 950404004 | Steve Wolfe | Shot #950404004
--------------- Ef3 only test to see if F14 is working or not It looks ok, just a bad low order bit on the digitizer. |
| Apr 4 1995 10:04:37:290AM | 950404005 | Steve Wolfe | Shot #950404005
--------------- Br offset from 3e-3 to 2e-3 Drop IC_OH1 from 16600 to 16100. Earlier breakdown (12msec) Radial field looks better, null is more open. |
| Apr 4 1995 10:14:46:580AM | 950404006 | Steve Wolfe | Shot #950404006
--------------- Drop IC_EF4 from 1300 to 1270. Breakdown later (15msec) Null looks excellent. Bz may be a little late coming in. |
| Apr 4 1995 10:21:38:050AM | 950404007 | Steve Wolfe | Shot #950404007
--------------- Raise fill to 2.1e-5 Fizzle, bd at 10msec. |
| Apr 4 1995 10:27:57:440AM | 950404008 | Steve Wolfe | Shot #950404008
--------------- Raise fill to 2.5e-5 Fizzle. bd at 10msec, less current. Needs a field tweak. |
| Apr 4 1995 10:38:13:070AM | 950404009 | Steve Wolfe | Shot #950404009
--------------- EF4 from 1270 to 1255 Another fizzle. Bd at .007 s |
| Apr 4 1995 10:39:04:210AM | 950404009 | Steve Wolfe | Shot #950404009
--------------- EF4 from 1270 to 1255 Another fizzle. Bd at .007 s |
| Apr 4 1995 10:48:35:760AM | 950404010 | Steve Wolfe | Shot #950404010
--------------- EF4 from 1255 to 1225 Note TF current is set for 103kA, we're getting 97; it's going to lowtaps at -.03 sec Fizzle. Still at 7msec |
| Apr 4 1995 10:56:55:800AM | 950404011 | Steve Wolfe | Shot #950404011
--------------- Change RCUR offset from 8000. to 0. Fizzle. less current. Bz certainly comes in faster. Now maybe too fast. |
| Apr 4 1995 11:07:49:560AM | 950404012 | Steve Wolfe | Shot #950404012
--------------- Change RCUR offset from 0. to 4000. Fizzle. Another late breakdown! Didn't change anything before 10msec |
| Apr 4 1995 11:17:43:200AM | 950404013 | Steve Wolfe | Shot #950404013
--------------- Drop EF4 from 1225 to 1200 Fizzle. Breakdown is later, around 15msec. |
| Apr 4 1995 11:25:49:160AM | 950404014 | Steve Wolfe | Shot #950404014
--------------- Put RCUR offset back to 8000, just to see. It turns on at 7.9msec. Fizzle. BD at 12msec |
| Apr 4 1995 11:38:39:320AM | 950404015 | Steve Wolfe | Shot #950404015
--------------- Put RCUR back to 4000. Change EF4 from 1200 to 1250. Fizzle. BD at 10msec (H-alpha) |
| Apr 4 1995 11:47:55:290AM | 950404016 | Steve Wolfe | Shot #950404016
--------------- Put EF4 to 1370 (Joe is insisting we try a very much more positive Bz) Fizzle BD at 18msec. That was too far. |
| Apr 4 1995 12:02:25:280PM | 950404017 | Steve Wolfe | Shot #950404017
--------------- Put EF4 back to to 1250 V_OH1 20V more negative between 10 and 15 msec. Drop fill to 2.1e-5 Fizzle, bd at 10msec Null looks good. Bz now may be too slow? |
| Apr 4 1995 12:13:12:050PM | 950404018 | Steve Wolfe | Shot #950404018
--------------- Delay PG by 3msec. RCUR offset to 0. from 4000. Fizzle. BD at 8msec |
| Apr 4 1995 12:27:56:090PM | 950404019 | Steve Wolfe | Shot #950404019
--------------- RCUR offset to 4000. to 2000. INcrease V_OH1 another 20V more negative between 10 and 15msec, and another 20 between 15 and 20msec Fizzle. BD earlier (6.5msec). A tiny bit more current. It looks better. |
| Apr 4 1995 12:32:55:120PM | 950404020 | Steve Wolfe | Shot #950404020
--------------- Drop fill to 1.8e-5 Didn't help. Very similar |
| Apr 4 1995 12:44:31:910PM | 950404021 | Steve Wolfe | Shot #950404021
--------------- Put another 20V on OH1 between 20 and 30msec Still fizzling. BD a tiny bit later. |
| Apr 4 1995 12:54:17:650PM | 950404022 | Steve Wolfe | Shot #950404022
--------------- Br from 2e-3 to 3e-3. EF4 15a more negative (1235) FIzzle slightly earlier bd |
| Apr 4 1995 01:15:54:510PM | 950404023 | Steve Wolfe | Shot #950404023
--------------- Br from 3e-3 to 1e-3. Lasted longer. Got into segment 2, but current stopped at 400kA Density is weird. RCUR is thrashing like mad. |
| Apr 4 1995 01:31:12:930PM | 950404024 | Steve Wolfe | Shot #950404024
--------------- RCUR in segment 2 to 2000. NL04 gain on at 8 at segment switch. Fizzle got to 40ka and bounced, looks like outside |
| Apr 4 1995 01:36:34:600PM | 950404025 | Steve Wolfe | Shot #950404025
--------------- Raise fill to 2.2e-5 Fizzle. Still bounces |
| Apr 4 1995 01:49:35:970PM | 950404026 | Steve Wolfe | Shot #950404026
--------------- Drop V_OH1 20 v more positive at .015 and .020 Another one. This one restrikes and almost makes it, gets to nearlu 80kA. |
| Apr 4 1995 02:07:08:160PM | 950404027 | Steve Wolfe | Shot #950404027
--------------- Another 20V more positive on the 15 and 20msec points Fill to 2.5e-5 Made it longer, but still disrupts early at 500msec Disrupting all through. |
| Apr 4 1995 02:14:03:810PM | 950404028 | Steve Wolfe | Shot #950404028
--------------- Drop early NL_04 gain and eliminate early point in NL_04 waveform. Fizzle. Bounces at 25msec. |
| Apr 4 1995 02:15:00:470PM | 950404028 | Steve Wolfe | Shot #950404028
--------------- Drop early NL_04 gain and eliminate early point in NL_04 waveform. Fizzle. Bounces at 25msec. |
| Apr 4 1995 02:26:52:200PM | 950404029 | Steve Wolfe | Shot #950404029
--------------- Change RCUR offset from 2000 to 1000 in seg 1 & 2 Drop early NL_04 gain and eliminate early point in NL_04 waveform. Finally, a shot that made it all the way through. Still has a funny pause in the current at 180msec |
| Apr 4 1995 02:46:27:210PM | 950404030 | Steve Wolfe | Shot #950404030
--------------- Move 375ka point on Ip to 100msec LOad EF2_by_EF4 and IC_EF4 wires from seg 3 Nice shot. EF2's go to zero early in rampdown though. |
| Apr 4 1995 02:58:57:810PM | 950404031 | Steve Wolfe | Shot #950404031
--------------- Ask for CLEARIN ramping from .005 to .0075 Increase NL_04 to 7e19 Ran ok, we're only getting 630kA. The Ip offset strikes again; we were asking for 680. Some unpleasantness at 400msec |
| Apr 4 1995 03:22:19:130PM | 950404032 | Steve Wolfe | Shot #950404032
--------------- Ask for 750kA. CLEARIN to .009 ramping to .0135 Rcur to .662 from .66 Raise NL_04 to 8e19 Died early at 200msec No obvious reason; there seems to be Moly problem. |
| Apr 4 1995 03:31:22:470PM | 950404033 | Steve Wolfe | Shot #950404033
--------------- Repeat: Ask for 750kA. CLEARIN to .009 ramping to .0135 Rcur to .662 from .66 Raise NL_04 to 8e19 Same thing. |
| Apr 4 1995 03:45:12:330PM | 950404034 | Steve Wolfe | Shot #950404034
--------------- Slow down density ramp and CLEARIN. This is somewhat weird. That worked. Got 700kA that time Left gap 1.6cm, right gap 2.4 cm |
| Apr 4 1995 03:58:51:630PM | 950404035 | Steve Wolfe | Shot #950404035
--------------- Ask for 900kA to get 850. Ran through. Got 845kA. Gaps look good. Still a burst of halpha around .4sec |
| Apr 4 1995 04:20:09:680PM | 950404036 | Steve Wolfe | Shot #950404036
--------------- Reducxe NL_04 gain to 4 Delay CLEARIN integral gain to .37sec RF firing at 1 sec Disrupted at 1.03 sec. RF tripped out, so I don't know why it disrupted. |
| Apr 4 1995 04:35:42:290PM | 950404037 | Steve Wolfe | Shot #950404037
--------------- Raise Ip by 100ka (ask for 1MA, should get 950kA) Disrupted at about 1 sec OH1 current limit was at 20kA and we are reaching it. Also EF1U is on the voltage rail. |
| Apr 4 1995 04:51:19:970PM | 950404038 | Steve Wolfe | Shot #950404038
--------------- Reduce NL_04 by .1e20 Increase OH1 current limit to 25kA in reverse direction Disrupted in flattop, at 700msec. |
| Apr 4 1995 05:13:20:220PM | 950404039 | Steve Wolfe | Shot #950404039
--------------- Increase NL_04 to 1.0e20 This one ran through. Slight vertical glitch at the time of the disruptions on 36 and 37. Only got to .9e20 |
| Engineering Operator Comments | ||||
| Shot | Time | Type | Status | Comment |
| 1 | 08:30:41:260AM | Plasma | Ok | no faults |
| 2 | 08:56:11:260AM | Plasma | Ok | no faults |
| 3 | 09:26:10:610AM | Plasma | Ok | no faults |
| 4 | 09:45:01:810AM | Test | Ok | ef3 only, checking for a bad flux loop |
| 5 | 09:56:39:890AM | Plasma | Ok | no faults |
| 6 | 10:07:45:040AM | Plasma | Ok | no faults |
| 7 | 10:17:36:370AM | Plasma | Ok | no faults |
| 8 | 10:24:57:740AM | Plasma | Ok | no faults |
| 9 | 10:34:29:460AM | Plasma | Ok | no faults |
| 10 | 10:42:36:590AM | Plasma | Ok | no faults |
| 11 | 10:50:53:370AM | Plasma | Ok | no faults |
| 12 | 11:00:03:130AM | Plasma | Ok | no faults |
| 13 | 11:10:49:550AM | Plasma | Ok | no faults |
| 14 | 11:20:56:500AM | Plasma | Ok | no faults |
| 15 | 11:34:52:030AM | Plasma | Ok | no faults |
| 16 | 11:43:32:900AM | Plasma | Ok | no faults |
| 17 | 11:55:03:490AM | Plasma | Ok | no faults |
| 18 | 12:06:36:870PM | Plasma | Ok | no faults |
| 19 | 12:19:27:320PM | Plasma | Ok | no faults |
| 20 | 12:29:29:810PM | Plasma | Ok | no faults |
| 21 | 12:37:28:880PM | Plasma | Ok | no faults |
| 22 | 12:48:45:970PM | Plasma | Ok | No faults. |
| 23 | 12:57:13:990PM | Plasma | Ok | No Faults. |
| 24 | 01:24:52:390PM | Plasma | Ok | No faults. |
| 25 | 01:32:52:420PM | Plasma | Ok | No Faults. |
| 26 | 01:41:03:610PM | Plasma | Ok | No Faults. |
| 27 | 01:52:11:440PM | Plasma | Ok | No Faults. |
| 28 | 02:10:51:950PM | Plasma | Ok | No faults. |
| 29 | 02:19:12:540PM | Plasma | Ok | No Faults. |
| 30 | 02:34:27:560PM | Plasma | Ok | No Faults. |
| 31 | 02:52:27:920PM | Plasma | Ok | No faults. |
| 32 | 03:10:52:070PM | Plasma | Ok | No Faults. |
| 33 | 03:25:09:050PM | Plasma | Ok | No Faults. |
| 34 | 03:36:32:790PM | Plasma | Ok | NO Faults. |
| 35 | 03:50:37:320PM | Plasma | Ok | no faults |
| 36 | 04:05:33:590PM | Plasma | Ok | No Faults. |
| 37 | 04:22:22:610PM | Plasma | Ok | No Faults. |
| 38 | 04:39:29:350PM | Plasma | Ok | No Faults. |
| 39 | 04:52:38:400PM | Plasma | Ok | no faults |