| Miniproposals | ||||||||||||
|
| Operators | |
| Session leader(s): | Steve Wolfe,T.C. Hender |
| Physics operator(s): | Ian Hutchinson |
| Engineering operator(s): | Unknown |
| Engineering Operator Run Comment |
| MP#361 Identity Experitments with JET on field locked mode thresholds |
| Session Leader Plans |
| Physics Operators Plans |
| Session Leader Summaries |
| Entered: Jul 7 2004 03:49:35:507PM |
| Author: T.C. Hender |
| Session Leaders' Summary for Friday, Dec 19, 2003 MP#361 Identity Experiments with JET on error field locked mode thresholds SL: Hender, Wolfe PO: Hutchinson Run Plan --------- The goal of today's run is to begin the sequence of C-Mod shots for the identity match with JET. The minimal goal is to identify the maximum density at which we can induce a locked mode with the A-coil in the chosen configuration (+Btop -Dbot -Gtop +Jtop). This will define the parameters for the JET experiments, to be carried out in January. Once this is accomplished, we will proceed to estimate the effect of our intrinsic error fields, and test an alternate configuration (+Dtop +Dbot -Jtop -Jbot). If there is time, we will run additional densities as called for in the MP, getting as much of the C-Mod program done as time permits (with the exception of the 8T, 1.9MA case). Note that if we somehow managed to get to the point of running the 4T point, we will lose the ECE, since this probably a grating change. Remaining C-Mod points will be done following the JET experiments, probably during the Summer campaign. Shot Sequence: -------------- A) Establish 1.27MA, 5.7T JET-shape equilibrium at nebar=3.5e20 (nl04=2.1e20) with A-coil off (waveform zeroed). Confirm q95=3.2 (tweak Bt if necessary). Verify shape match. We may need NINJA puff in D2 to access the high density. [6 shots] B1) turn on A-coil to maximum current (program 4000A, should limit on PLC to 3500A) reaching programmed current at or just after beginning of flattop of density, current. Program nl04 to decrease during shot to identify onset of locked mode. If no locked mode occurs reduce starting density and try again. If locked mode appears at the beginning of the Acoil pulse raise nl04 and try again. [1-2 shots] B2) Based on results of B1, run flattop density which results in locked mode at lowest possible OH1 current, i.e. earliest in flattop, to minmize intrinsic error field. Note values of intrinsic B11, B21, B31 as calculated from model. [2-3 shots] C) Repeat B with A-coil current reversed to determine maximum locking density in this configuration. The idea is to get a handle on the magnitude of the intrinsic field effect. [3-4 shots] In principle, B and C are all JET needs to do their part of the experiment. Even just completing B would probably do if it had too. If we take the whole run getting through this amount, it will still be a success. Hoever, we really want to do some more. D) With the A-coil off, determine the low density threshold for intrinsic locked modes (hopefully quite a bit lower, but I would bet on 1 to 1.5e20.) To the extent possible, this should be done near the same oh1 current as in B and C, which will be later in the pulse at lower density. This will help quantify the absolute intrinsic error in this configuration. [3-5shots] E) For the polarity of B and C which gave the lower locking density. which presumably corresponds to lower net error field, try to determine the a-coil current which suppresses the locked mode obtained in D. This will further help quantify the intrinsic error magnitude and phase, and help refine the model. [3 shots] F) Change A-coil configuration to (+Dtop +Dbot -Jtop -Jbot) and repeat step B to find the highest locking density at beginning of flattop. Depending on the results of C, D, and E, we may decide that this step is better done in reverse current, i.e. (-Dtop -Dbot +Jtop +Jbot).[3-4 shots] G) Repeat F with reversed current if time permits. [3 shots] H) In the unlikely event there is more time available, pick an A-coil configuration and fill in intermediate density points determining the current that induces locking (with the same Oh1 current) at lower density. Start with half-way between the maximum density and the density at which it locks with the intrinsic field alone. Results: --------- The above plan proved to be far too ambitious. In the end, not even the "minimal goal" of identifying the maximum density at which we can induce a locked mode with the A-coil in the chosen configuration was achieved, although the actual limiting considerations were clarified. We did succeed in establishing the desired equilibrium, at Ip~1.27MA, Bt=6.1T (at the nominal R=0.66m, not at Rmagx~0.685) with q95~3.2 and a good match to the JET shape. The maximum practical density for further locking experiments at these parameters seems to be in the range of 5.5 scaling from lower density shots at applied fields less than half the maximum available implies we should be able to do so. The highest density for which a locked mode was observed was nebar~3.6e20/m^3 (shot #28, for example), with an A-coil current of only 1000A, compared to the maximum 3500A limit. Intrinsic locked modes (with no A-coil current) were observed at nebar~2.6e20/m^3; many of these appeared to be associated with small injections observed on the 2pi diode bolometer. Contrary to expectations, the main difficulty encountered was an inability to reliably raise the density to levels substantially above that at which the intrinsic error field alone induced locked modes. Two factors contributed to this effect. First, not so unexpectedly, the normal gas puff from the piezo valve was insufficient to get the density higher than about 3e20/m^3 (nl04~1.8). Using a NINJA inner-wall capillary we were able to get up to 6.5e20/m^3 (shot#11) and, at the end of the run again to 5.5e20/m^3 (shot#31). However, both of these shots disrupted, apparently due to vertical instability. The EF1U supply was running to its current rail of 5kA, trying to maintain the JET upper triangularity, and this seemed to eventually lead to an increase in elongation and n/n_crit, although neither of these parameters reached levels that had not been previously run successfully. The volt-second consumption was ultimately the other limiting consideration. Not only does the intrinsic error field increase at higher flux swing, mostly due to the OH1 terms, but the railing of EF1U prevents us from maintaining the desired shape. All of the highest density cases had loop voltages around 2 volts and exhibited cooling down to Te0< 1keV, even in the absence of locked modes. A major SNAFU which also contributed to the lack of success was that the A-coil configuration specified in the run plan (see above) is incorrect. The correct starting configuration, as called for in the MP, is [+Btop -Dbot -Gtop +Jbot] but this was incorrectly transcribed (by smw) to a configuration including JTOP instead of JBOT. The resulting 2/1 field is not only smaller than that of the correct setting by a factor of two, it is aligned so as to partly suppress the intrinsic field error. As a result, we observed that shot#11, at maximum A-coil current, did not encounter a locked mode, and (probably) erroneously concluded that nebar=6.5e20 was above the maximum locking threshold, leading us to back off on the gas puff. The error was realized only when we decided to reverse the A-coil current at shot#18. All of shots #18-31 were carried out with the correct coils included, in the reverse orientation [-Btop +Dbot +Gtop -Jbot]. Earlier shots with A-coil energized, #9,11,15,16,17, may be of some interest in constraining the model of the intrinsic error, but are not useful for the JET comparison, since they have the wrong m spectrum. Essentially all of the shots in this run terminated in disruptions, two of which generated halo current warnings at the I*B>1500 Amp-Tesla level. Startups after disruptions were problematic, and we ended up with a large number of fizzles (see Physop Summary). After several of the disruptions we blew fuses in power supplies, necessitating additional delays to hi-pot the SCR's and change the fuse. On shot#29 the TCI feedback failed, turning off the piezo valve and resulting in a lower density than expected, despite having turned up the demand on the NINJA. Shot#31 was run with the piezo pre-programmed for max gas throughout the shot; this shot was also supposed to have a pellet, but the injector failed to fire. Interesting shots from this run include: Intrinsic locked modes, or small Acoil current: 7,8,9(?),16,17, 18(?),19(?),20,25,26, Locked modes with Acoil: 24,27,28,29, No locked mode: 11,22,31 For future experiments in this line, we should either employ an additional piezo (B-side lower could be used if we put the Argon elsewhere (mixed in B-top?), or B-side upper if we have purged the He3), or run with the NINJA at 35-40psi and turning on early; the last shot had NINJA on at 0.2sec for 0.5sec. We don't know whether pellet fueling would be helpful or not, but we might want to keep the option open. The goal should probably be to get the density up fast, so we don't encounter intrinsic locked modes before we get to the maximum. We will certainly need to do both polarities, as planned but not done today, in order to try to bracket the intrinsic error. |
| Physics Operator Summaries |
| Entered: Jul 7 2004 04:37:20:130PM |
| Author: Ian Hutchinson |
| MP#361 "Identity Experiments with JET on error field locked mode thresholds" SL: Hender, wolfe PO: Hutchinson Summary _______ This attempt to probe the upper density limit of locked mode accessiblility at high current (1.27MA) proved to be difficult mostly because locked modes occurred all the way to the highest densities we were readily able to get to; even with quite modest adverse applied asymmetric field. In addition, locked modes were sometimes ambiguous even though the disruptions were really clear! There were nevertheless some shots which added to our locked-mode parameter space and we seem to be able to specify some density thresholds with moderate applied asymmetric field. We are going to claim a world record locked mode density. At least \bar{n_e}=3.6e20 m^-3, thomson n_e0 about 3.2. (Shot 29 needs phase jump correction). Shot 31 went to higher density and had no locked mode. The required JET shape and scaled current were matched very well with q_95 about 3.2 at Bt=6.1T. Practically every shot disrupted as we were pushing very hard with the gas puff. Quite a few fizzles, but not surprising given all the disruptions. The first part of the run was done with an erroneously specified A-coil connection. From shot 18 on, the correct configuration (+-C) was used. Thus two different applied phases/spectra were explored. Scorecard _________ Shot,Duration(s),Ipmax(MA) Shot,Duration(s),Ipmax 1 0.952 1.012 2 0.000 0.046 3 0.000 0.050 4 0.000 0.053 5 1.891 0.965 6 0.000 0.052 7 1.451 1.232 8 1.473 1.284 9 1.517 1.289 10 0.000 0.060 11 1.350 1.300 12 0.000 0.065 13 0.000 0.057 14 0.000 0.051 15 0.613 1.330 16 1.585 1.290 17 1.518 1.285 18 1.423 1.483 19 1.260 1.360 20 1.584 1.290 21 0.000 0.054 22 1.491 1.284 23 0.000 0.040 24 1.168 1.378 25 1.326 1.335 26 1.424 1.331 27 1.096 1.338 28 1.096 1.368 29 1.453 1.279 30 0.000 0.062 31 1.391 1.315 Finished summary for 1031219 Total of 31 shots. 31 shots. 20 plasmas. 11 fizzles. 0 duds. Details. ________ ---------------------------------------------------------------------------- 1031219xxx hutch PHYSICS_OPERATOR Dec 18 2003 2:53:01:640PM . . . . . . . . . . . . . . . . . . . . Preliminary PCS setup Open PCS safe Import seg 2 from 1021104008. Got warning about sundry stuff. Acknowledge. This has the title 0.8MA SN, Preprogram Gas, but this is actually a feedback case. In all Vs set A-coil cur to zero. In all Vs set TF current to -158kA. Ip to 1 MA. Pulse gas 3 V to 100 in segment 2 from .1 to .67s. nl04 to 1.4 at .5s. Save as shot 2 in /home/hutch/scratch/ ---------------------------------------------------------------------------- 1031219xxx hutch PHYSICS_OPERATOR Dec 18 2003 2:58:11:923PM . . . . . . . . . . . . . . . . . . . . Engineering Setup ----------------- Power Systems as on 1031216001 except: TF current limit at 175kA Reverse current limits on OH1, OH2U, OH2L to -30kA EF4 reverse current limit to -10kA Acoils configured +Btop -Dbot -Gtop +Jtop with PLC settings V=600V, I=3kA Gas setup fill B-Top with 6 psi D2 Hybrid enabled (PG4) fill B-side lower with 1 psi Ar Hybrid enabled (PG1) leave B-side upper as is Hybrid DISABLED (PG2) fill C-side with 30 psi D2 Hybrid enabled (PG3) N.B. NINJA: fill the Lower Capilary (NINJA) with 35psi Deuterium RF Setup - NO RF Requested Gate valve permissives for the usual suspects (ECE, VUV, DNB) assuming no vacuum issues. Communications -------------- Hender will be communicating from JET via either the Access Grid or H323 (Gnomemeeting on our linux boxes). Wolfe will be local co-Session Leader and mostly be doing the communication with the Physop. Fallback communications will be either a chat room or a trans-Atlantic phone call. Final fallback would be using reply_user or reply_node on a cmodws workstation. Run Plan --------- The goal of today's run is to begin the sequence of C-Mod shots for the identity match with JET. The minimal goal is to identify the maximum density at which we can induce a locked mode with the A-coil in the chosen configuration (+Btop -Dbot -Gtop +Jtop). This will define the parameters for the JET experiments, to be carried out in January. Once this is accomplished, we will proceed to estimate the effect of our intrinsic error fields, and test an alternate configuration (+Dtop +Dbot -Jtop -Jbot). If there is time, we will run additional densities as called for in the MP, getting as much of the C-Mod program done as time permits (with the exception of the 8T, 1.9MA case). Note that if we somehow managed to get to the point of running the 4T point, we will lose the ECE, since this probably a grating change. Remaining C-Mod points will be done following the JET experiments, probably during the Summer campaign. Shot Sequence: -------------- A) Establish 1.27MA, 5.7T JET-shape equilibrium at nebar=3.5e20 (nl04=2.1e20) with A-coil off (waveform zeroed). Confirm q95=3.2 (tweak Bt if necessary). Verify shape match. We may need NINJA puff in D2 to access the high density. [6 shots] B1) turn on A-coil to maximum current (program 4000A, should limit on PLC to 3500A) reaching programmed current at or just after beginning of flattop of density, current. Program nl04 to decrease during shot to identify onset of locked mode. If no locked mode occurs reduce starting density and try again. If locked mode appears at the beginning of the Acoil pulse raise nl04 and try again. [1-2 shots] B2) Based on results of B1, run flattop density which results in locked mode at lowest possible OH1 current, i.e. earliest in flattop, to minmize intrinsic error field. Note values of intrinsic B11, B21, B31 as calculated from model. [2-3 shots] C) Repeat B with A-coil current reversed to determine maximum locking density in this configuration. The idea is to get a handle on the magnitude of the intrinsic field effect. [3-4 shots] In principle, B and C are all JET needs to do their part of the experiment. Even just completing B would probably do if it had too. If we take the whole run getting through this amount, it will still be a success. Hoever, we really want to do some more. D) With the A-coil off, determine the low density threshold for intrinsic locked modes (hopefully quite a bit lower, but I would bet on 1 to 1.5e20.) To the extent possible, this should be done near the same oh1 current as in B and C, which will be later in the pulse at lower density. This will help quantify the absolute intrinsic error in this configuration. [3-5shots] E) For the polarity of B and C which gave the lower locking density. which presumably corresponds to lower net error field, try to determine the a-coil current which suppresses the locked mode obtained in D. This will further help quantify the intrinsic error magnitude and phase, and help refine the model. [3 shots] F) Change A-coil configuration to (+Dtop +Dbot -Jtop -Jbot) and repeat step B to find the highest locking density at beginning of flattop. Depending on the results of C, D, and E, we may decide that this step is better done in reverse current, i.e. (-Dtop -Dbot +Jtop +Jbot).[3-4 shots] G) Repeat F with reversed current if time permits. [3 shots] H) In the unlikely event there is more time available, pick an A-coil configuration and fill in intermediate density points determining the current that induces locking (with the same Oh1 current) at lower density. Start with half-way between the maximum density and the density at which it locks with the intrinsic field alone. ---------------------------------------------------------------------------- 1031219xxx hutch PHYSICS_OPERATOR Dec 19 2003 9:03:52:273AM . . . . . . . . . . . . . . . . . . . . Load from shot 2 in scratch area. Load clean: improper output on p_09. Go into bolofeed and make sure the controller is zeroed. Load clean: OK A-coil configuration is -C (Bt,-Db,-Gt,Jt). ---------------------------------------------------------------------------- 1031219001 hutch PHYSICS_OPERATOR Dec 19 2003 9:21:44:700AM . . . . . . . . . . . . . . . . . . . . Plasma Disrupts at .94s. Lost vertical control Control decides to give the plasma a push at .93s. zxu to 4 cm from 6. Rcur to .665 was .663 ---------------------------------------------------------------------------- 1031219002 hutch PHYSICS_OPERATOR Dec 19 2003 9:34:40:100AM . . . . . . . . . . . . . . . . . . . . Fizzle. Ip to 600kA at .1s ---------------------------------------------------------------------------- 1031219003 hutch PHYSICS_OPERATOR Dec 19 2003 9:46:21:650AM . . . . . . . . . . . . . . . . . . . . Fizzle. Tile currents remain rather high. Need 4500 times Vloop to compensate. That disruption shook us up a lot. Gas puff to 19ms from 20ms. ICEF4 to -1340 from -1335 ---------------------------------------------------------------------------- 1031219004 hutch PHYSICS_OPERATOR Dec 19 2003 9:59:10:420AM . . . . . . . . . . . . . . . . . . . . Fizzles. Pulse gas duration to 15ms (top) Br offset to 0 from .5mT ---------------------------------------------------------------------------- 1031219005 hutch PHYSICS_OPERATOR Dec 19 2003 10:14:08:690AM . . . . . . . . . . . . . . . . . . . . Plasma. Ip to 1.27. 650kA at .1s. nl04 to 1.6 rxu to 3cm ---------------------------------------------------------------------------- 1031219006 hutch PHYSICS_OPERATOR Dec 19 2003 10:26:25:086AM . . . . . . . . . . . . . . . . . . . . Fizzle. Fill puff to 14ms. ---------------------------------------------------------------------------- 1031219007 hutch PHYSICS_OPERATOR Dec 19 2003 10:50:53:626AM . . . . . . . . . . . . . . . . . . . . Plasma. Disrupts at 1.44s. Locked mode at 1.35, in rampdown. Got 1.22MA Gas 3 V full till .9s. nl04 to 2e20 and raise earlier. Ip to 1.32MA demand. TF to 164kA demand, proportional increase. RXU to -2cm from -3cm. ---------------------------------------------------------------------------- 1031219008 hutch PHYSICS_OPERATOR Dec 19 2003 11:05:21:336AM . . . . . . . . . . . . . . . . . . . . Plasma disrupts at same time. Locked mode at 1.3s nl04 dropping to 1.5. Excellent shape agreement. Bt to 170kA. A-coil to 4000 from .89 to end of shot. ---------------------------------------------------------------------------- 1031219009 hutch PHYSICS_OPERATOR Dec 19 2003 11:19:34:920AM . . . . . . . . . . . . . . . . . . . . Plasma disrupts at 1.5s in ramp down. 3.45 kA on A-coil. GPC not helpful because of grating setting. Turn on NINJA. At .5s. ---------------------------------------------------------------------------- 1031219010 hutch PHYSICS_OPERATOR Dec 19 2003 11:34:27:160AM . . . . . . . . . . . . . . . . . . . . Fizzle. Fill pressure has gone up to .035. Ninja to .35s Fill puff to 13ms. Acoil start at .6s ---------------------------------------------------------------------------- 1031219011 hutch PHYSICS_OPERATOR Dec 19 2003 11:49:07:730AM . . . . . . . . . . . . . . . . . . . . Plasma. Big gas puff. Disrupts as 1.33. Got nl04 3.78. No obvious locked mode. Ninja to .3 start, .2 duration (from .5 duration). ---------------------------------------------------------------------------- 1031219012 hutch PHYSICS_OPERATOR Dec 19 2003 12:07:17:406PM . . . . . . . . . . . . . . . . . . . . Fizzle Tweak ef3 v DOWN TO 2500 at 5 and 12ms. ---------------------------------------------------------------------------- 1031219013 hutch PHYSICS_OPERATOR Dec 19 2003 12:14:57:800PM . . . . . . . . . . . . . . . . . . . . Fizzle. Very small change on Bz ramp. Tweak EF3 down to 2400V. ---------------------------------------------------------------------------- 1031219014 hutch PHYSICS_OPERATOR Dec 19 2003 12:28:24:413PM . . . . . . . . . . . . . . . . . . . . Fizzle. Import segment 1 from 1031219011. Error message for p_04 05 06 08 in segment 1. Tweaked the offending traces. ---------------------------------------------------------------------------- 1031219015 hutch PHYSICS_OPERATOR Dec 19 2003 12:45:13:250PM . . . . . . . . . . . . . . . . . . . . Plasma. Disrupts at .65 Ninja to .5s Turn off ninja. A-coil ramps from .6 to 1.3s. ---------------------------------------------------------------------------- 1031219016 hutch PHYSICS_OPERATOR Dec 19 2003 12:58:38:300PM . . . . . . . . . . . . . . . . . . . . Plasma till ramp-down. 1.56. A good imagination might suggest a locked mode at about .75s. Change Acoil to ramp starting at .8s at the same rate. ---------------------------------------------------------------------------- 1031219017 hutch PHYSICS_OPERATOR Dec 19 2003 1:29:44:670PM . . . . . . . . . . . . . . . . . . . . Plasma till rampdown. Locked mode at .9s just prior to A-coil, perhaps. But there is an injection at that time. Reverse A-coil polarity to but on reflection this is not actually +C, should have been jbot instead of jtop. Swap to jbot as required. Timing start back to .6 Turn ninja on. ---------------------------------------------------------------------------- 1031219018 hutch PHYSICS_OPERATOR Dec 19 2003 1:49:41:446PM . . . . . . . . . . . . . . . . . . . . Plasma till 1.4s. Turn off ninja. Acoil turned on harder .6-.7s. ---------------------------------------------------------------------------- 1031219019 hutch PHYSICS_OPERATOR Dec 19 2003 2:01:55:043PM . . . . . . . . . . . . . . . . . . . . Plasma till 1.2 Apparent locked mode at .66s. But ambiguous. Set A-coil current to zero. ---------------------------------------------------------------------------- 1031219020 hutch PHYSICS_OPERATOR Dec 19 2003 2:14:32:893PM . . . . . . . . . . . . . . . . . . . . Plasma till 1.57s Apparent locked mode at .86s. (Intrinsic) Turn on ninja at .4s for .3s. Leave acoil off. ---------------------------------------------------------------------------- 1031219021 hutch PHYSICS_OPERATOR Dec 19 2003 2:25:37:663PM . . . . . . . . . . . . . . . . . . . . Fizzle. No changes. ---------------------------------------------------------------------------- 1031219022 hutch PHYSICS_OPERATOR Dec 19 2003 2:46:33:796PM . . . . . . . . . . . . . . . . . . . . Plasma. Disrupts at 1.46. No clear locked mode. Looks as if ne is high enough A-coil current 4000 ramp from .8 to .9. ---------------------------------------------------------------------------- 1031219023 hutch PHYSICS_OPERATOR Dec 19 2003 2:59:37:533PM . . . . . . . . . . . . . . . . . . . . Fizzle. Pressure seems to have nearly doubled. CII high. Pressure rises at -.6s (before the puff). Looks like someone has a big pressure in a diagnostic. Try again. ---------------------------------------------------------------------------- 1031219024 hutch PHYSICS_OPERATOR Dec 19 2003 3:16:02:040PM . . . . . . . . . . . . . . . . . . . . Plasma till 1.17s Locked mode at .956s very clear. Set acoil current to 2000. ------------------ |
| Entered: Jul 7 2004 04:37:20:147PM |
| Author: Ian Hutchinson |
| --------------------------------------------------------- 1031219025 hutch PHYSICS_OPERATOR Dec 19 2003 3:26:43:513PM . . . . . . . . . . . . . . . . . . . . Plasma till 1.3s Density is lower. Apparent locked mode at .76s. But injection at that time. Refill ninja plenum. ---------------------------------------------------------------------------- 1031219026 hutch PHYSICS_OPERATOR Dec 19 2003 3:40:20:066PM . . . . . . . . . . . . . . . . . . . . Plasma till 1.4s. Hardly any difference in density. May be a locked mode at .74s. Xray burst coincides. Raise Ninja and bring earlier. ---------------------------------------------------------------------------- 1031219027 hutch PHYSICS_OPERATOR Dec 19 2003 4:00:13:276PM . . . . . . . . . . . . . . . . . . . . Plasma till 1.1s, nl04 2.1e20. Locked mode at .966s, during the applied error. Acoil demand to 1500A. ---------------------------------------------------------------------------- 1031219028 hutch PHYSICS_OPERATOR Dec 19 2003 4:30:01:803PM . . . . . . . . . . . . . . . . . . . . Plasma till 1.1 s. Locked mode at 1s. Acoil 1000A obtained. Upped the ninja puff. ---------------------------------------------------------------------------- 1031219029 hutch PHYSICS_OPERATOR Dec 19 2003 4:40:33:776PM . . . . . . . . . . . . . . . . . . . . Plasma. Locked at 1.12s. Gas feedback turned off because of fringe loss. Set gas puff full on till 1.3s Acoil start at .9s. ---------------------------------------------------------------------------- 1031219030 hutch PHYSICS_OPERATOR Dec 19 2003 4:56:40:470PM . . . . . . . . . . . . . . . . . . . . Fizzle. Add pellet at .7s ---------------------------------------------------------------------------- 1031219031 hutch PHYSICS_OPERATOR Dec 19 2003 5:03:12:770PM . . . . . . . . . . . . . . . . . . . . Plasma to 1.3s. Pellet did not appear. No obvious locked mode. Density got to nl04=3.3e20. |
| Session Leader Comments | |||
| Dec 19 2003 07:33:49:050AM | Steve Wolfe | Getting set up for today's joint experiment with Tim Hender of JET. Ian has already posted the run plan. Tried to log onto the AccessGrid and get the endlessly flipping hourglass. Sent email to Ti Legget at AG, and to Hender and Steve.Cooper at JET. We may have to start off using write and/or telephones, since the ANL folk are probably still asleep. | |
| Dec 19 2003 08:15:36:550AM | Steve Wolfe | Managed to connect with Steve Cooper at JET using OpenH323 and we found a codec and setting that seem to work. For the record, the audio codec is g.711-uLaw-64k with enable silence detection off and the upper jitter buffer setting moved from 500ms to 800ms. Steve reports sound quality is adequate on his end; seems fine here. AG can go back to sleep. | |
| Dec 19 2003 09:19:35:263AM | 1031219002 | Steve Wolfe | Shot#1: Plasma disrupted at .947sec vertical instability |
| Dec 19 2003 09:20:52:763AM | 1031219002 | Steve Wolfe | Shot#2: fizzle |
| Dec 19 2003 09:23:24:310AM | 1031219002 | Steve Wolfe | Shot#2: fizzle next shot: try again |
| Dec 19 2003 09:36:11:613AM | 1031219003 | Steve Wolfe | Shot#3: While we're at it, fix the early current prog. in Seg2 Another fizzle |
| Dec 19 2003 09:49:35:340AM | 1031219004 | Steve Wolfe | Shot#4: Another fizzle. |
| Dec 19 2003 10:12:02:800AM | 1031219005 | Steve Wolfe | Shot#5: Plasma full length next shot: go to 1.27MA, nl4=1.6e20 |
| Dec 19 2003 10:15:55:897AM | 1031219006 | Steve Wolfe | Shot#6: go to 1.3MA, nl4=1.6e20 fizzle. |
| Dec 19 2003 10:36:51:247AM | 1031219007 | Steve Wolfe | Shot#7: go to 1.3MA, nl4=1.6e20 plasma to 1.45, locked mode at 1.35 For some reason the rampdown starts at 1.3sec q95 is 3.15 next shot: raise nl4 to 2 tweak shape a little more. |
| Dec 19 2003 11:00:54:147AM | 1031219008 | Steve Wolfe | Shot#8: raise nl4 to 2 some shape tweaks, raise field and current about 5% plasma to 1.46sec, locked mode at 1.2sec at nl4=1.5e20 peak density is 1.9sec. q95=3.1 next shot: tweak field up to get 3.2 on q, turn on acoil at 0.8-0.9sec to 1.5 |
| Dec 19 2003 11:10:49:307AM | 1031219009 | Steve Wolfe | Shot#9: tweak field up to get 3.2 on q, turn on acoil at 0.8-0.9sec to 1.5 plasma to 1.55s. possible locked mode at .83sec Amanda is changing the grating. next shot: more gas (raise density, use NINJA |
| Dec 19 2003 11:26:52:877AM | 1031219010 | Steve Wolfe | Shot#10: more gas (raise density, use NINJA puff starts at 0.5sec nl4 program set to 3e20! fizzle, NINJA went anyway, gas hits at .62, maybe later than we wanted next shot: move NINJA to .35sec |
| Dec 19 2003 11:42:24:227AM | 1031219011 | Steve Wolfe | Shot#11: move NINJA to .35sec; still ask for nl4=3e20 move acoil earlier disrupts at 1.33sec No locked mode I can see. next shot: NINJA start to .3 and duration down to .2 (from .5) |
| Dec 19 2003 11:49:54:930AM | 1031219012 | Steve Wolfe | Shot#12: NINJA start to .3 and duration down to .2 (from .5) fizzle |
| Dec 19 2003 12:03:48:110PM | 1031219013 | Steve Wolfe | Shot#13: NINJA start to .3 and duration down to .2 (from .5) fizzle again. |
| Dec 19 2003 12:14:54:567PM | 1031219014 | Steve Wolfe | Shot#14: fizzle. |
| Dec 19 2003 12:37:27:137PM | 1031219015 | Steve Wolfe | Shot#15: plasma to .65, doesn't make it to the acoil either an dinjection or we're gassing it to death. next shot: delay ninja to .5sec |
| Dec 19 2003 12:41:15:310PM | 1031219015 | Steve Wolfe | Shot#16: Change of plans. Try turning off NINJA, ramping Acoil |
| Dec 19 2003 01:02:12:067PM | 1031219016 | Steve Wolfe | Shot#16: Change of plans. Try turning off NINJA, ramping Acoil plasma. possible locked mode at .77 For shot 17, move acoil start later by 200msec |
| Dec 19 2003 01:16:41:760PM | 1031219017 | Steve Wolfe | Shot#17:move acoil start later by 200msec locked mode starts at 0.9sec, just as the acoil comes on. Next shot: reverse the current in the acoil Damn! I put the wrong configuration in the run plan. Just noticed it. We've been running +Btop -Dbot -Gtop +Jtop when it should have been +Jbot. For the next shot, fix it, in the negative polarity, i.e. -Btop +Dbot +Gtop -JBOT |
| Dec 19 2003 01:41:33:550PM | 1031219018 | Steve Wolfe | Shot#18: plasma to 1.45sec There is a change in the sawteeth around .8, but no clear magnetic signature. NOTE: The tap information did not get entered in the engineering pad, so all the phase information in the tree is wrong for this shot. I'll fix it later. |
| Dec 19 2003 03:24:22:983PM | 1031219018 | Steve Wolfe | Shot#18: Modified tap connection values in the tree for Acoils to correspond to what was actually done on this shot: -Btop +Dbot +Gtop -Jbot |
| Dec 19 2003 01:56:59:370PM | 1031219019 | Steve Wolfe | Shot#19: plasma. Unconvincing locked mode candidate around .7sec next shot: acoil off |
| Dec 19 2003 02:10:00:733PM | 1031219020 | Steve Wolfe | Shot#20: acoil off plasma to 1.55sec possible locked mode at .85sec turn the ninja on again to raise the density |
| Dec 19 2003 02:15:28:110PM | 1031219021 | Steve Wolfe | Shot#21: turn the ninja on again to raise the density; still acoil off fizzle. |
| Dec 19 2003 02:32:54:260PM | 1031219022 | Steve Wolfe | Shot#22: turn the ninja on again to raise the density; still acoil off plasma to 1.5sec, density reaches nl4 of 2, then climbs to 3 at the end. Probably poloidal detachment. No obvious locked mode at this density. next shot: turn on acoil at 0.8sec |
| Dec 19 2003 02:47:26:733PM | 1031219023 | Steve Wolfe | Shot#23: turn on acoil at 0.8sec fizzle |
| Dec 19 2003 02:55:41:020PM | 1031219023 | Steve Wolfe | Shot#23: turn on acoil at 0.8sec fizzle . Seems to be a pressure rise starting around -0.6sec, before the pre-puff. No gate valves seem to have any problem. |
| Dec 19 2003 03:05:09:490PM | 1031219024 | Steve Wolfe | Shot#24: turn on acoil at 0.8sec plasma to 1.15sec got a locked mode at .95sec or so. next shot: drop the acoil current to 2000 |
| Dec 19 2003 03:20:58:043PM | 1031219025 | Steve Wolfe | Shot#25: drop the acoil current to 2000 plasma, to 1.3. Density is lower. Locked mode at .77? NINJA plenum was depleted; topped off again. |
| Dec 19 2003 03:36:51:673PM | 1031219026 | Steve Wolfe | Shot#26: drop the acoil current to 2000 plasma to 1.4sec. Density os still low Intrinsic locked mode at .73sec |
| Dec 19 2003 03:49:45:397PM | 1031219027 | Steve Wolfe | Shot#27: Move NINJA to .3 and increassse pressure. We need to get the density up faster to avoid this intrinsic locked mode. plasma to 1.1sec Locked mode at .97sec applied field is .0005. next shot: drop acoil current again by 500A |
| Dec 19 2003 04:09:14:500PM | 1031219028 | Steve Wolfe | Shot#28: drop acoil current again by 500A plasma to 1.1sec, locked mode at 1.0sec Next shot: NINJA start at .2 and duration .5 This is about as much as we can get from NINJA |
| Dec 19 2003 04:33:23:320PM | 1031219029 | Steve Wolfe | Shot#29: NINJA start at .2 and duration .5 (was .3 and .3) This is about as much as we can get from NINJA plasma to 1.4. TCI feedback failed, and gas turned off. locked mode starts at 1.16sec |
| Dec 19 2003 04:44:54:747PM | 1031219030 | Steve Wolfe | Shot#30: Program gas full on to 1.3sec, Acpi; delayed to 0.9sec fizzle for the last shot, put a pellet in at 0.7sec. |
| Dec 19 2003 05:31:44:000PM | 1031219031 | Steve Wolfe | Shot#31:for the last shot, put a pellet in at 0.7sec. 1.3sec long, no locked mode. No pellet. May have been an empty barrel? Gas puff got to nl04=3.3e20, 50% higher than 28; this corresponds to 5.5e20/m^3. TS says peak density is 4e20/m^3, so the last rise after 1.2 sec could be a detachment. I need to look at the profiles. Don't know why it disrupted, unless it really did poloidally detach and shrink to the density limit. But there is no sign of a locked mode. |
| Physics Operator Comments | |||
| Dec 18 2003 02:53:01:640PM | Ian Hutchinson | Preliminary PCS setup Open PCS safe Import seg 2 from 1021104008. Got warning about sundry stuff. Acknowledge. This has the title 0.8MA SN, Preprogram Gas, but this is actually a feedback case. In all Vs set A-coil cur to zero. In all Vs set TF current to -158kA. Ip to 1 MA. Pulse gas 3 V to 100 in segment 2 from .1 to .67s. nl04 to 1.4 at .5s. Save as shot 2 in /home/hutch/scratch/ | |
| Dec 18 2003 02:58:11:923PM | Ian Hutchinson | Engineering Setup ----------------- Power Systems as on 1031216001 except: TF current limit at 175kA Reverse current limits on OH1, OH2U, OH2L to -30kA EF4 reverse current limit to -10kA Acoils configured +Btop -Dbot -Gtop +Jtop with PLC settings V=600V, I=3kA Gas setup fill B-Top with 6 psi D2 Hybrid enabled (PG4) fill B-side lower with 1 psi Ar Hybrid enabled (PG1) leave B-side upper as is Hybrid DISABLED (PG2) fill C-side with 30 psi D2 Hybrid enabled (PG3) N.B. NINJA: fill the Lower Capilary (NINJA) with 35psi Deuterium RF Setup - NO RF Requested Gate valve permissives for the usual suspects (ECE, VUV, DNB) assuming no vacuum issues. Communications -------------- Hender will be communicating from JET via either the Access Grid or H323 (Gnomemeeting on our linux boxes). Wolfe will be local co-Session Leader and mostly be doing the communication with the Physop. Fallback communications will be either a chat room or a trans-Atlantic phone call. Final fallback would be using reply_user or reply_node on a cmodws workstation. Run Plan --------- The goal of today's run is to begin the sequence of C-Mod shots for the identity match with JET. The minimal goal is to identify the maximum density at which we can induce a locked mode with the A-coil in the chosen configuration (+Btop -Dbot -Gtop +Jtop). This will define the parameters for the JET experiments, to be carried out in January. Once this is accomplished, we will proceed to estimate the effect of our intrinsic error fields, and test an alternate configuration (+Dtop +Dbot -Jtop -Jbot). If there is time, we will run additional densities as called for in the MP, getting as much of the C-Mod program done as time permits (with the exception of the 8T, 1.9MA case). Note that if we somehow managed to get to the point of running the 4T point, we will lose the ECE, since this probably a grating change. Remaining C-Mod points will be done following the JET experiments, probably during the Summer campaign. Shot Sequence: -------------- A) Establish 1.27MA, 5.7T JET-shape equilibrium at nebar=3.5e20 (nl04=2.1e20) with A-coil off (waveform zeroed). Confirm q95=3.2 (tweak Bt if necessary). Verify shape match. We may need NINJA puff in D2 to access the high density. [6 shots] B1) turn on A-coil to maximum current (program 4000A, should limit on PLC to 3500A) reaching programmed current at or just after beginning of flattop of density, current. Program nl04 to decrease during shot to identify onset of locked mode. If no locked mode occurs reduce starting density and try again. If locked mode appears at the beginning of the Acoil pulse raise nl04 and try again. [1-2 shots] B2) Based on results of B1, run flattop density which results in locked mode at lowest possible OH1 current, i.e. earliest in flattop, to minmize intrinsic error field. Note values of intrinsic B11, B21, B31 as calculated from model. [2-3 shots] C) Repeat B with A-coil current reversed to determine maximum locking density in this configuration. The idea is to get a handle on the magnitude of the intrinsic field effect. [3-4 shots] In principle, B and C are all JET needs to do their part of the experiment. Even just completing B would probably do if it had too. If we take the whole run getting through this amount, it will still be a success. Hoever, we really want to do some more. D) With the A-coil off, determine the low density threshold for intrinsic locked modes (hopefully quite a bit lower, but I would bet on 1 to 1.5e20.) To the extent possible, this should be done near the same oh1 current as in B and C, which will be later in the pulse at lower density. This will help quantify the absolute intrinsic error in this configuration. [3-5shots] E) For the polarity of B and C which gave the lower locking density. which presumably corresponds to lower net error field, try to determine the a-coil current which suppresses the locked mode obtained in D. This will further help quantify the intrinsic error magnitude and phase, and help refine the model. [3 shots] F) Change A-coil configuration to (+Dtop +Dbot -Jtop -Jbot) and repeat step B to find the highest locking density at beginning of flattop. Depending on the results of C, D, and E, we may decide that this step is better done in reverse current, i.e. (-Dtop -Dbot +Jtop +Jbot).[3-4 shots] G) Repeat F with reversed current if time permits. [3 shots] H) In the unlikely event there is more time available, pick an A-coil configuration and fill in intermediate density points determining the current that induces locking (with the same Oh1 current) at lower density. Start with half-way between the maximum density and the density at which it locks with the intrinsic field alone. | |
| Dec 19 2003 09:03:52:273AM | Ian Hutchinson | Load from shot 2 in scratch area. Load clean: improper output on p_09. Go into bolofeed and make sure the controller is zeroed. Load clean: OK A-coil configuration is -C (Bt,-Db,-Gt,Jt). | |
| Dec 19 2003 09:21:44:700AM | 1031219001 | Ian Hutchinson | Plasma Disrupts at .94s. Lost vertical control Control decides to give the plasma a push at .93s. zxu to 4 cm from 6. Rcur to .665 was .663 |
| Dec 19 2003 09:34:40:100AM | 1031219002 | Ian Hutchinson | Fizzle. Ip to 600kA at .1s |
| Dec 19 2003 09:46:21:650AM | 1031219003 | Ian Hutchinson | Fizzle. Tile currents remain rather high. Need 4500 times Vloop to compensate. That disruption shook us up a lot. Gas puff to 19ms from 20ms. ICEF4 to -1340 from -1335 |
| Dec 19 2003 09:59:10:420AM | 1031219004 | Ian Hutchinson | Fizzles. Pulse gas duration to 15ms (top) Br offset to 0 from .5mT |
| Dec 19 2003 10:14:08:690AM | 1031219005 | Ian Hutchinson | Plasma. Ip to 1.27. 650kA at .1s. nl04 to 1.6 rxu to 3cm |
| Dec 19 2003 10:26:25:087AM | 1031219006 | Ian Hutchinson | Fizzle. Fill puff to 14ms. |
| Dec 19 2003 10:50:53:627AM | 1031219007 | Ian Hutchinson | Plasma. Disrupts at 1.44s. Locked mode at 1.35, in rampdown. Got 1.22MA Gas 3 V full till .9s. nl04 to 2e20 and raise earlier. Ip to 1.32MA demand. TF to 164kA demand, proportional increase. RXU to -2cm from -3cm. |
| Dec 19 2003 11:05:21:337AM | 1031219008 | Ian Hutchinson | Plasma disrupts at same time. Locked mode at 1.3s nl04 dropping to 1.5. Excellent shape agreement. Bt to 170kA. A-coil to 4000 from .89 to end of shot. |
| Dec 19 2003 11:19:34:920AM | 1031219009 | Ian Hutchinson | Plasma disrupts at 1.5s in ramp down. 3.45 kA on A-coil. GPC not helpful because of grating setting. Turn on NINJA. At .5s. |
| Dec 19 2003 11:34:27:160AM | 1031219010 | Ian Hutchinson | Fizzle. Fill pressure has gone up to .035. Ninja to .35s Fill puff to 13ms. Acoil start at .6s |
| Dec 19 2003 11:49:07:730AM | 1031219011 | Ian Hutchinson | Plasma. Big gas puff. Disrupts as 1.33. Got nl04 3.78. No obvious locked mode. Ninja to .3 start, .2 duration (from .5 duration). |
| Dec 19 2003 12:07:17:407PM | 1031219012 | Ian Hutchinson | Fizzle Tweak ef3 v DOWN TO 2500 at 5 and 12ms. |
| Dec 19 2003 12:14:57:800PM | 1031219013 | Ian Hutchinson | Fizzle. Very small change on Bz ramp. Tweak EF3 down to 2400V. |
| Dec 19 2003 12:28:24:413PM | 1031219014 | Ian Hutchinson | Fizzle. Import segment 1 from 1031219011. Error message for p_04 05 06 08 in segment 1. Tweaked the offending traces. |
| Dec 19 2003 12:45:13:250PM | 1031219015 | Ian Hutchinson | Plasma. Disrupts at .65 Ninja to .5s Turn off ninja. A-coil ramps from .6 to 1.3s. |
| Dec 19 2003 12:58:38:300PM | 1031219016 | Ian Hutchinson | Plasma till ramp-down. 1.56. A good imagination might suggest a locked mode at about .75s. Change Acoil to ramp starting at .8s at the same rate. |
| Dec 19 2003 01:29:44:670PM | 1031219017 | Ian Hutchinson | Plasma till rampdown. Locked mode at .9s just prior to A-coil, perhaps. But there is an injection at that time. Reverse A-coil polarity to but on reflection this is not actually +C, should have been jbot instead of jtop. Swap to jbot as required. Timing start back to .6 Turn ninja on. |
| Dec 19 2003 01:49:41:447PM | 1031219018 | Ian Hutchinson | Plasma till 1.4s. Turn off ninja. Acoil turned on harder .6-.7s. |
| Dec 19 2003 02:01:55:043PM | 1031219019 | Ian Hutchinson | Plasma till 1.2 Apparent locked mode at .66s. But ambiguous. Set A-coil current to zero. |
| Dec 19 2003 02:14:32:893PM | 1031219020 | Ian Hutchinson | Plasma till 1.57s Apparent locked mode at .86s. (Intrinsic) Turn on ninja at .4s for .3s. Leave acoil off. |
| Dec 19 2003 02:25:37:663PM | 1031219021 | Ian Hutchinson | Fizzle. No changes. |
| Dec 19 2003 02:46:33:797PM | 1031219022 | Ian Hutchinson | Plasma. Disrupts at 1.46. No clear locked mode. Looks as if ne is high enough A-coil current 4000 ramp from .8 to .9. |
| Dec 19 2003 02:59:37:533PM | 1031219023 | Ian Hutchinson | Fizzle. Pressure seems to have nearly doubled. CII high. Pressure rises at -.6s (before the puff). Looks like someone has a big pressure in a diagnostic. Try again. |
| Dec 19 2003 03:16:02:040PM | 1031219024 | Ian Hutchinson | Plasma till 1.17s Locked mode at .956s very clear. Set acoil current to 2000. |
| Dec 19 2003 03:26:43:513PM | 1031219025 | Ian Hutchinson | Plasma till 1.3s Density is lower. Apparent locked mode at .76s. But injection at that time. Refill ninja plenum. |
| Dec 19 2003 03:40:20:067PM | 1031219026 | Ian Hutchinson | Plasma till 1.4s. Hardly any difference in density. May be a locked mode at .74s. Xray burst coincides. Raise Ninja and bring earlier. |
| Dec 19 2003 04:00:13:277PM | 1031219027 | Ian Hutchinson | Plasma till 1.1s, nl04 2.1e20. Locked mode at .966s, during the applied error. Acoil demand to 1500A. |
| Dec 19 2003 04:30:01:803PM | 1031219028 | Ian Hutchinson | Plasma till 1.1 s. Locked mode at 1s. Acoil 1000A obtained. Upped the ninja puff. |
| Dec 19 2003 04:40:33:777PM | 1031219029 | Ian Hutchinson | Plasma. Locked at 1.12s. Gas feedback turned off because of fringe loss. Set gas puff full on till 1.3s Acoil start at .9s. |
| Dec 19 2003 04:56:40:470PM | 1031219030 | Ian Hutchinson | Fizzle. Add pellet at .7s |
| Dec 19 2003 05:03:12:770PM | 1031219031 | Ian Hutchinson | Plasma to 1.3s. Pellet did not appear. No obvious locked mode. Density got to nl04=3.3e20. |
| Engineering Operator Comments | ||||
| Shot | Time | Type | Status | Comment |
| 1 | 09:01:50:867AM | Plasma | Ok | |
| 2 | 09:18:44:187AM | Plasma | Ok | |
| 3 | 09:31:48:427AM | Plasma | Ok | |
| 4 | 09:44:20:867AM | Plasma | Ok | |
| 5 | 09:57:11:920AM | Plasma | Ok | |
| 6 | 10:12:04:987AM | Plasma | Ok | |
| 7 | 10:24:39:900AM | Plasma | Ok | |
| 8 | 10:49:00:423AM | Plasma | Ok | |
| 9 | 11:02:30:913AM | Plasma | Ok | |
| 10 | 11:17:14:170AM | Plasma | Ok | |
| 11 | 11:32:28:347AM | Plasma | Ok | |
| 12 | 11:47:18:773AM | Plasma | Ok | |
| 13 | 12:00:08:467PM | Plasma | Ok | |
| 14 | 12:12:55:627PM | Plasma | Ok | |
| 15 | 12:26:21:850PM | Plasma | Ok | |
| 16 | 12:43:20:890PM | Plasma | Ok | |
| 17 | 12:56:00:580PM | Plasma | Ok | |
| 18 | 01:28:06:657PM | Plasma | Ok | |
| 19 | 01:47:29:727PM | Plasma | Ok | |
| 20 | 01:59:59:683PM | Plasma | Ok | |
| 21 | 02:12:47:533PM | Plasma | Ok | |
| 22 | 02:25:14:007PM | Plasma | Ok | |
| 23 | 02:44:46:093PM | Plasma | Ok | |
| 24 | 02:57:58:550PM | Plasma | Ok | |
| 25 | 03:11:46:337PM | Plasma | Ok | |
| 26 | 03:24:44:107PM | Plasma | Ok | |
| 27 | 03:41:30:597PM | Plasma | Ok | |
| 28 | 03:57:46:887PM | Plasma | Bad | PFbreaker opened durshot. Blown fuse OH2U |
| 29 | 04:24:58:100PM | Plasma | Ok | |
| 30 | 04:41:12:167PM | Plasma | Ok | |
| 31 | 04:54:18:203PM | Plasma | Ok | |