Miniproposals

Miniproposal: Date Filed: Title: First Author: Session Leader: Bruce Lipschultz (shots 1-10)

Miniproposal: 095 Date Filed: 3/8/1995 Title: Demonstrate Remote Control of C-Mod First Author: Steve Horne Session Leader: Brian Labombard (shots 11-19)

Miniproposal: 097a Date Filed: 3/9/1995 Title: Fast disruption termination using pellets First Author: Robert Granetz Session Leader: Robert Granetz (shots 20-37)

Engineering Operator Run Comment

livermore control

Session Leader Plans

Physics Operators Plans

Session Leader Summaries

Entered: Jul 7 2004 03:49:12:833PM

Author: To Be Determined

Session leader summary for part C of run 950329. SL: R. Granetz PO: J. Goetz EO: J. Daigle This part of the run is for MP#097, which is a proposal to mitigate the effects of vde disruptions by killing them quickly using impurity pellet injection. The idea is to cause an abnormally fast current quench after the vde is detected, hopefully terminating the plasma before it can move very far off the midplane. This run is in response to a request from ITER, which proposed this `killer pellet' idea in order to mitigate thermal damage and electromagnetic stresses to its divertor hardware. We will use lithium pellets doped with 100 micrograms of gold. Start with any decent (i.e. non-disrupting) diverted, 0.8 MA plasma, preferably with kappa=1.6-1.7. Turn off the ZCUR gain at 0.7 s and observe the plasma disruption characteristics for several shots (dI/dt, halo currents, zcentroid, etc). Determine when to fire the lithium pellet injector so as to hit the plasma when it has moved 2-3 cm from its initial position. Fire gold-doped pellets at the pre-determined time and observe dI/dt, halo currents (incl. at the midplane), zcentroid, filament reconstructions, etc. Determine whether the doped pellets kill the disruption before it moves much vertically. If we have time, try firing just plain lithium pellets, and also fire tungsten using laser ablation. ********************************************************************** Summary of physics results: The ECE polychrometer shows the following: Pellet status Thermal quench behavior no Li, no Au several millisecond decay time Li, no Au Te drops to 350 eV in 100-200 microseconds, followed by a partial re-heat Li, Au (300 ug) Te drops to 100 eV in 100 us & stays there. However, even though the gold was very efficient at radiating away the electron thermal energy extremely quickly, the current quench was only speeded up by about 2 ms compared to non-gold-injection shots. This was not fast enough to prevent the plasma from hitting the bottom of the machine. Also, halo currents were within the usual range on all shots. ********************************************************************** This part of the run starts with shot 950329020. Shot 020 --- reload shot 012 from earlier today. Good shot. No disruption. nl_04=1.0e20 m-2. Next shot: turn off all slow and fast ZCUR gains at 0.7 s. Shot 021 --- Good disruption at 0.718 s. Ihalo_l=131 kA, dIp/dt=0.5 MA/ms. The plasma has moved 2 cm at about time 0.710 s. Next shot: repeat. It's taking an incredibly long time to cool one TF arm. Shot 022 --- Good disruption at 0.721 s. Ihalo_l=135 kA, dIp/dt=0.5 MA/ms. The plasma has moved 2 cm at about time 0.713 s. Next shot: fire gold-doped large lithium pellet at 0.710 s. Shot 023 --- Pellet hit at 0.710 s, but the plasma just appeared to swallow it without much change in speed. Jim Terry reports no gold seen with McPherson. Darren has some pellets with 3 times as much gold (300 micrograms). Next shot: fire in lithium pellet dopedwith 300 micrograms of gold. Shot 024 --- Pellet hit at 0.711 s, but again the plasma didn't die any faster than on previous shots, even though this pellet had 300 ug of Au. No gold radiation observed. Next shot: try a smaller lithium pellet w/ 100 ug of Au, since the large ones are going all the way through the plasma. Shot 025 --- Pellet hit at 0.710 s, with similar lack of effect. Next shot: raise Te by lowering density from nl=1.0 to 0.6e20 m-2 in order to help ablation (suggestion from Joe Snipes). Use large, 300 microgram Au doped pellet. Shot 026 --- Pellet. This quench was faster, but we don't have a baseline yet at this lower density. Te was much hotter (2.5 vs 1.7 keV). Spectroscopy finally saw gold on that shot! No, No, that report has now been denied. Next shot: repeat, again with 300 ug of Au in large pellet. Shot 027 --- Pellet. This quench was also fast, but we won't know anything for sure until we get the baseline shot. There was an injection of something else at 0.68 s, which may obscure the gold injection, so I'll repeat this shot. Next shot: repeat, again with 300 ug of Au in large pellet. Shot 028 --- Pellet. Similar to shot 026. Next shot: repeat, but with no pellet. This will be our baseline VDE. Shot 029 --- No pellet, but there was a natural molybdenum injection at 0.68 s which screwed up things. Must repeat. Next shot: repeat with no pellet, to get a VDE baseline. Shot 030 --- No pellet, good baseline VDE. It looks like the pellet is killing the disruption about 2 ms faster than without a pellet. It is not clear yet whether this is due to gold, or just lithium. Next shot: repeat with a plain (un-doped) lithium pellet. Shot 031 --- Pellet, but plain lithium (no gold doping). It does seem that it's the gold that causes the disruption to quench 2 ms faster than without gold. Next shot: laser ablation of tungsten. Shot 032 --- Tungsten injection using laser ablation. Current quench was even slower than the baseline shot. Open up the cell so that Darren can load several solid chunks of gold into the injector. When he's done, we should be able to get a couple more shots. Amanda reports that the ECE shows shots 26 and 28 (which had Li/Au) cooled down to 100 eV in about 100 usec. Shot 30 (which had no pellet) cooled down in several msec, and Shot 31 (which had Li, but no Au) cooled down to 350 eV in about 100 usec and then reheated some. So that gold is very efficient at radiating away the thermal energy. Current quench, although faster, is not as fast as we wanted. Shot 033 --- This shot will be a VDE, but without any pellet injection. Result, runaway screamer! Lot's of hards. Next shot: raise pre-fill and try again. Shot 034 --- Ugly, disruptive shot, with lots of moly injections. Next shot: try again. Shot 035 --- Plasma, made it to the programmed VDE. Several moly injections. Next shot: fire in the solid gold pellet. Shot 036 --- Fired solid gold pellet, but neither Darren nor Jim Terry sees any sign of it. Because of the greatly increased pellet mass, Darren is not sure how long the pellets should take to hit the plasma. Next (and last) shot: since the solid gold pellet timing is not known well enough, make the next shot a normal, non-disruptive, plasma, and fire the gold pellets at 0.7 s. Shot 037 --- Plasma, but no disruption. There were one or two small injections of something, but the pellet tracker sees it stop at R=80 cm, so it wasn't a macroscopic gold pellet. No macroscopic effect on the plasma. There was also a large (moly?) injection at 0.78 s. End of run

Entered: Jul 7 2004 03:49:12:850PM

Author: To Be Determined

Session Leader Run Summary for 950329B Continuation of MP# 95 - Run C-Mod from Remote LLNL Site PO: Horne SL: LaBombard EO: Bertolino This run was a continuation of remote control operation of C-Mod from the LLNL site. The run plan was to "dial up" the interesting RF H-mode of shot 25 from 950328 for further study. There was some hint that the divertor was in a partially detached state during the H-Mode phase on this shot (low divertor Te). We had hoped to get the scanning probe into these types of plasmas and to optimize the detached-H-mode phase, if it in fact could be achieved. John Goetz (first session PO) and Bruce Lipschultz (SL?) took shots 1-12 starting from a reload of shot#950328025 in preparation for the remote run. LLNL control of the run began with shot 13. Steve H. loaded a 2 segment version of shot 12 and changed the density program to 1.2e20. The following results were obtained during the 7 shot session: Shot 13 NL4=1.2E20. FSP did not fire (disabled by RF during the previous shot). H-mode at .84 sec just after the start of the 1 MW RF pulse. Divertor remains attached at the separatrix during the H-mode phase. 14 NL4=1.35E20. FSP Fired. Again an H-mode phase after start of 1.3 MW RF pulse. A short ELM-free period was evident. Divertor Te s less than 3 eV are spuriously seen during the H-mode phase. It is not clear that the divertor is detached during these times. 15 Attempted to puff D2 through NINJA but it did not go. A few more ELM-Free H-Modes during the 1.3 MW RF pulse. Again, the divertor Te goes low during the H-mode phase (3-6 eV) but the pressure is peaked at the strike point. We may be able to reconstruct the FSP position trace during the RF-H-mode phase using a non-RF shot. This would be a better indicator of detachment. 16 NINJA puff went. We got a good flat NL4=1.4e20. Turned RF off to get a calibration for the second FSP scan. 17 Turned RF back on with NINJA puff and FSP. Nice ELM-Free H-mode periods. Again, low divertor temperatures are seen. Pressure is still peaked near the separatrix. If the divertor IS attached, then these shots are exceptions to the rule: "the divertor alway detaches for Te below 5 ev" and is interesting from that viewpoint. 18 Changed NL4 to 1.5e20 with NINJA. RF cut out before any H-Mode transition. The second probe scan went cleanly. We can use this for a position calibration. Divertor re-attaches during high power RF pulse. Low power RF pulse (0.7 MW) did not re-attach the divertor. 19 RF on. NINJA on. FSP fired. Short H-Mode. Last FSP scan missed the H-Mode. Probe data was not processed for this shot. Will be processed tonight. - a very productive series of shots. We will look at these in some detail to assess the detachment question. More could be done to achieve H-modes with a detached divertor including higher plasma density and/or impurity gas puffing. Control returned to MIT for shot 20.

Physics Operator Summaries

Entered: Jul 7 2004 04:36:53:660PM

Author: To Be Determined

Run 950329, extension of remote run. LaBombard (SL) Horne (PO) Bertolino (EO) We ran from LLNL from 11:00 to 1:00 MIT time. This was a valuable addition to yesterday's experience. It turns out that there was (is) a problem at Fermilab which was causing 10% - 15% packet loss on the internet. This is much worse than it sounds because every lost packet requires a bunch of handshaking and exchange of information, each packet of which is subject to the ping time delay and potentially further lost packets. Today the local ESNET experts were able to route us around that problem. There were still some lost packets but it was down to the 5% level. In addition, Mark London found a way to move the MBONE audio/video traffic to a path which did not conflict with the path used by X and RPC. The result was a vastly improved response of the interactive tools. Even the logbook was not much worse than usual. (Brian gave up on it yesterday, but used it extensively today.) Our run plan was to further investigate further what looked like simultaneous H-mode and divertor detachment we saw on 930328025. The MIT part of the run had a few fizzles; I ran scatterplot at Steve W's request and saw nothing particularly unusual on shots 6 and 7. I also checked a couple of shots in our part of the run. We took over from J. Goetz after shot 12; (11:04) we used a 2-segment PCS to minimize load time, though network response was so much better than yesterday that it probably wasn't necessary. Fill was 1.6e-5 throughout, A side at 18 lbs. Shot log is short; everything worked routinely; all shots went. Brian is excited about the physics, see his report. shot t_init 13 11:19 nl to 1.2e20. 14 11:32 nl to 1.4e20 but no ninja, to evaluate how much extra gas we might need. 15 11:48 ninja at .335 sec, 50 msec pulse, 20 lbs. It may not have opened. 16 12:03 ninja to 80msec. Worked this time. No RF. 17 12:15 RF back on. 18 12:32 nel to 1.5e20 Disappointing RF. 19 12:48 Good RF.

Entered: Jul 7 2004 04:36:53:677PM

Author: To Be Determined

Physics operator summary for 950329 EO: Bertolino/Bertolino/Daigle PO: Goetz/Horne/Goetz SL: Goetz/LaBombard/Granetz Run 950329 was a hybrid run in support of two goals; continuation of the demonstration of the remote operation cabilities of Alcator C-Mod and Mini-Proposal #097 - Fast Disruption Termination Using Pellets. The goals of the first part of the run were to warm-up the machine and the RF and to tune up a shot suitable for the RES at LLNL. Control was then passed to the operators at the RES. The goals of the second part of the run were to inject metallic pellets into a VDE to terminate the plasma much more quickly than normal. Program for this run: 0830 - 1000 EST Load shot 950328025 make sure this shot runs tune up the RF 1000 - 1300 EST transfer control to LLNL RES continue MP from 950328 1300 - 1700 EST Run MP097 Start from shot 950321022 VDE's can be initiated at a fixed, repeatable time by turning off the ZCUR PID gains at some point during the flattop. After a few shots, it will be possible to determine the vertical motion of the plasma as a function of time and measure quench times, halo currents, etc, and to see how repeatable these are. Then enable the LPI, and set its trigger so that the pellet will hit the plasma after it has moved a given distance down... 5 cm seems reasonable. The pellets can be easily doped with small chips of metal. For this run, we will use 50-100 $\mu$g of gold, which should give about 50 MW of radiation, effectively getting rid of all the thermal energy in $\le1$ ms. (For spectroscopic diagnostic purposes, it would be desirable to use something that doesn't occur naturally in the plasma). Two different lithium pellet sizes should be available. Measurements to be made include pellet speed, penetration distance, $\Delta n_e/n_e$, $T_e$, $P_{\rm rad}$, as well as the disruption characteristics already mentioned. Filament reconstructions will show how far the plasma moves, and particular attention should be paid to the vertical array of Rogowski segments on the inboard wall. This program was completely carried out, although there were some modifications to the run plan as the run neared its end. See the Session Leader's summary for the morning and afternoon sessions to find out the details of the physics aspects of the run. Some random neural firings from today: -It took a while to get the plasmas running today. A fizzle-plasma pattern was finally broken on shot 007. There seemed to be a slight radial field problem and a high CII signal (>.004) during this section of the run. Lowering the fill to 1.6e-5 and tweaking Bz and Br put the run on easy street. There were current hesitations, but with low CII light, they all went. -It appears that holding EF4 at 2500A until 1.0sec relieves the demand on the EF1 voltages and the EF2 currents. This is a good thing! Even at 'high' densities, the supplies have room to do their jobs. It is highly recommended to increase the EF4 current to 2500A throughout the shot. Trying to hold the equilibrium established yesterday without this change was impossible. It was necessary to lower the density to 'medium' values in order to get shots to run. The team at the RES were able to successfully raise the density with this change in place and still maintain the desired equilibrium. -Recovery from disruptions was excellent today. Plasmas were obtained after all the induced disruptions from MP097. -A wait of ~40 minutes was endured while the LPI was turned into an AuPI. This wait was followed by a killer hard x-ray shot. Raising the fill from 1.6 to 2.1e-5 over the course of two shots chased away all the hard x-rays. Engineering, computing, and diagnostics today: No problems at all. Scorecard: 37 shots = 34 plasmas + 3 fizzles Shot summary for Run 950329 coldstart hybrid - all matrices respond 2 hours of D2 ECDC prior to the run Load shot 950328025 P_0 = 2.0e-5 Shot change result ____ _____ ______ 1 see above fizzle - late breakdown some radial field 2 BR_0 offset = 6.5e-3 plasma - disr. @ 0.89 b.d. earlier; still some Br vert. osc. @ 0.82 3 P_0=1.8e-5 fizzle - b.d. on the inside field o.k.; CII rad. high 4 P_0 = 1.6e-5 plasma - disr. @ 1.01 z-osc. @ 0.92; EF2U on the rail 5 RXU=-015 @ 1.0; ZXL P gain = 2 @ 0.85 fizzle - CII rad. high 6 IC_EF4 = -1085A (was -1070A) plasma - disr. @ 0.96 EF2U on rail @ 0.93; z-osc @0.85 7 RXU=0 @ 1.0; ZXU P gain = 6 plasma - disr. @ 0.90 EF2U not on rail, but EF1's at voltage limit 8 ZXU = .03 to help EF1U plasma - disr. @ 0.57 big Mo inj. @ 0.20 9 NL_04 = 1e20 plasma - all the way down almost lost it at 1.0sec 10 IC_EF4 = 2500A until 1.0sec plasma - all the way down slow down CLEARIN ramp in no vert. osc.; EF1 voltages and EF2 currents o.k. 11 stairstep off FSP and STRKPSI gains plasma - all the way down still a slight mismatch across ramp-down 12 RCUR=.6545 late to keep kappa flat plasma - all the way down less EFC thrash at ramp-down 13 hand-off to LLNL RES 20 grab control again plasma - all the way down reload 950329012 and start MP097 21 zero PID gains on ZCUR(2) & (3) @ 0.7 plasma - disrupted @ 0.718 22 no changes plasma - disrupted @ 0.720 23 no changes plasma - disrupted @ 0.717 24 no changes plasma - disrupted @ 0.717 25 no changes plasma - disrupted @ 0.716 26 NL_04 = 0.6e20 plasma - disrupted @ 0.712 27 no changes plasma - disrupted @ .711 28 no changes plasma - disrupted @ 0.712 29 baseline plasma - disrupted @ 0.7145 nat. Mo injection @ 0.68 30 repeat plasma - disrupted @ 0.714 31 med. Li pellet; no Au plasma - disrupted @ 0.7145 32 tungsten injection @ .707 plasma - disrupted @ 0.716 33 load solid Au pellet but don't fire plasma - disr. @ 0.43 killer hard x-ray shot 34 P_0 = 1.9e-5 plasma - disr. @ 0.53 large Mo inj. @ 0.5 killed it 35 no changes plasma - disr @ 0.719 hint o' hards; outside b.d. 36 fire solid Au pellet; P_0 = 2.1e-5 plasma - disr. @ 0.717 unknown if the Au made it 37 turn PID gains back on for ZCUR(2) plasma - all the way down and ZCUR(3) and let AuPI fire away no evidence of an Au pellet

Session Leader Comments
Mar 29 1995 09:56:36:990AM	950329007	Bruce Lipschultz	Run 950329 Engineering operator: V. Bertolino Physics Operator: J. Goetz Session Leader: 8:30-11:00 unknown 11:00-1:00 PM B. LaBombard 1:00-5:00 PM R. Granetz shot 6: nl04=1.4e20, disruption near end of shot. shot 7: same density but accomplished with NINJA pulse (100 ms with trigger @ .3 seconds with 20 PSI D2).
Mar 29 1995 10:03:30:340AM	950329008	Bruce Lipschultz	shot 8: NINJA trigger at .28 seconds for 90 ms, puffing through midplane capillary (B16-001). Still have disruption.. Problem may be early on with very large injection at 200ms.
Mar 29 1995 10:19:03:730AM	950329009	Bruce Lipschultz	shot 9: this shot made it at nl04=1.0e20 and NINJA off.
Mar 29 1995 10:42:50:570AM	950329010	Bruce Lipschultz	shot 10: This shot went fine again, nl04=1.e20. Possible H-mode at .9 seconds. John seems to have fixed a problem at current inversion with switching segments.
Mar 29 1995 11:02:41:150AM	950329011	Bruce Lipschultz	shot 11: same shot with scanning probe and PRF 900 kW.
Mar 29 1995 11:36:25:990AM	950329012	Bruce Lipschultz	shot 12: nl04=1.e20. PRF=1.1 MW. Transfer control to Livermore.
Mar 29 1995 11:49:04:910AM	950329013	Bruce Lipschultz	shot 13: nl04=1.2e20. PRF=1.1 MW. No FSP
Mar 29 1995 11:49:36:640AM	950329014	Bruce Lipschultz	shot 14: nl04=1.4e20. PRF=1.3 MW. FSP scan
Mar 29 1995 12:10:55:670PM	950329015	Bruce Lipschultz	shot 15: nl04=1.4e20, RF power = 1.5 MW with H-mode. FSP scan obtained.
Mar 29 1995 12:17:28:910PM	950329016	Bruce Lipschultz	shot 16: nl04=1.4e20, no RF power. Ninja pulse triggered at .355 seconds for 80 ms (20 PSI pressure D2). FSP scan obtained.
Mar 29 1995 12:18:30:750PM	950329016	Bruce Lipschultz	shot 16: nl04=1.4e20, no RF power. Ninja pulse triggered at .355 seconds for 80 ms (20 PSI pressure D2). FSP scan obtained.
Mar 29 1995 12:29:23:780PM	950329017	Bruce Lipschultz	shot 17: ELM-free H-mode periods. PRF of 1.5 MW. nl04 rises during H-mode from 1.4 - 1.7e20. NINJA used for this shot. 2 FSP scans.
Mar 29 1995 12:53:07:270PM	950329018	Bruce Lipschultz	shot 18: PRF - 1.5 MW. FSP scan. nl04 rises to over 2.e20 during H-mode.
Mar 29 1995 01:12:38:150PM	950329020	Robert Granetz	Shot 020 --- reload shot 012 from earlier today. Good shot. No disruption. nl_04=1.0e20 m-2. Next shot: turn off all slow and fast ZCUR gains at 0.7 s.
Mar 29 1995 04:25:23:320PM	950329020	Robert Granetz	his part of the run is for MP#097, which is a proposal to mitigate the effects of vde disruptions by killing them quickly using impurity pellet injection. The idea is to cause an abnormally fast current quench after the vde is detected, hopefully terminating the plasma before it can move very far off the midplane. This run is in response to a request from ITER, which proposed this `killer pellet' idea in order to mitigate thermal damage and electromagnetic stresses to its divertor hardware. We will use lithium pellets doped with 100 micrograms of gold.
Mar 29 1995 04:25:57:840PM	950329020	Robert Granetz	Start with any decent (i.e. non-disrupting) diverted, 0.8 MA plasma, preferably with kappa=1.6-1.7. Turn off the ZCUR gain at 0.7 s and observe the plasma disruption characteristics for several shots (dI/dt, halo currents, zcentroid, etc). Determine when to fire the lithium pellet injector so as to hit the plasma when it has moved 2-3 cm from its initial position. Fire gold-doped pellets at the pre-determined time and observe dI/dt, halo currents (incl. at the midplane), zcentroid, filament reconstructions, etc. Determine whether the doped pellets kill the disruption before it moves much vertically. If we have time, try firing just plain lithium pellets, and also fire tungsten using laser ablation. This part of the run starts with shot 950329020.
Mar 29 1995 01:28:30:420PM	950329021	Robert Granetz	Shot 021 --- Good disruption at 0.718 s. Ihalo_l=131 kA, dIp/dt=0.5 MA/ms. The plasma has moved 2 cm at about time 0.710 s. Next shot: repeat.
Mar 29 1995 01:29:00:470PM	950329022	Robert Granetz	It's taking an incredibly long time to cool one TF arm.
Mar 29 1995 01:38:38:390PM	950329022	Robert Granetz	Shot 022 --- Good disruption at 0.721 s. Ihalo_l=135 kA, dIp/dt=0.5 MA/ms. The plasma has moved 2 cm at about time 0.713 s. Next shot: fire gold-doped large lithium pellet at 0.710 s.
Mar 29 1995 01:53:01:730PM	950329023	Robert Granetz	Shot 023 --- Pellet hit at 0.710 s, but the plasma just appeared to swallow it without much change in speed. Jim Terry reports no gold seen with McPherson. Darren has some pellets with 3 times as much gold (300 micrograms). Next shot: fire in lithium pellet dopedwith 300 micrograms of gold.
Mar 29 1995 02:05:03:740PM	950329024	Robert Granetz	Shot 024 --- Pellet hit at 0.710 s, but again the plasma didn't die any faster than on previous shots, even though this pellet had 300 ug of Au. No gold radiation observed. Next shot: try a smaller lithium pellet w/ 100 ug of Au, since the large ones are going all the way through the plasma.
Mar 29 1995 02:13:00:770PM	950329025	Robert Granetz	Shot 025 --- Pellet hit at 0.710 s, with similar lack of effect. Next shot: raise Te by lowering density from nl=1.0 to 0.6e20 m-2 in order to help ablation (suggestion from Joe Snipes). Use large, 300 microgram Au doped pellet.
Mar 29 1995 02:22:34:220PM	950329026	Robert Granetz	Shot 026 --- Pellet. This quench was faster, but we don't have a baseline yet at this lower density. Te was much hotter (2.5 vs 1.7 keV). Next shot: repeat.
Mar 29 1995 02:24:02:600PM	950329026	Robert Granetz	Spectroscopists finally saw some gold on this shot!
Mar 29 1995 02:31:50:790PM	950329027	Robert Granetz	Shot 027 --- Pellet. This quench was also fast, but we won't know anything for sure until we get the baseline shot. There was an injection of something else at 0.68 s, which may obscure the gold injection, so I'll repeat this shot. Next shot: repeat, again with 300 ug of Au in large pellet
Mar 29 1995 02:54:32:480PM	950329028	Robert Granetz	Shot 028 --- Pellet. Similar to shot 026. Next shot: repeat, but with no pellet. This will be our baseline VDE.
Mar 29 1995 02:54:46:140PM	950329029	Robert Granetz	Shot 029 --- No pellet, but there was a natural molybdenum injection at 0.68 s which screwed up things. Must repeat. Next shot: repeat with no pellet, to get a VDE baseline.
Mar 29 1995 03:09:14:430PM	950329030	Robert Granetz	Shot 030 --- No pellet, good baseline VDE. It looks like the pellet is killing the disruption about 2 ms faster than without a pellet. It is not clear yet whether this is due to gold, or just lithium. Next shot: repeat with a plain (un-doped) lithium pellet.
Mar 29 1995 03:17:50:590PM	950329031	Robert Granetz	Shot 031 --- Pellet, but plain lithium (no gold doping). It does seem that it's the gold that causes the disruption to quench 2 ms faster than without gold. Next shot: laser ablation of tungsten.
Mar 29 1995 03:45:03:550PM	950329032	Robert Granetz	Shot 032 --- Tungsten injection using laser ablation. Current quench was even slower than the baseline shot. Open up the cell so that Darren can load several solid chunks of gold into the injector. When he's done, we should be able to get a couple more shots.
Mar 29 1995 04:50:56:910PM	950329035	Robert Granetz	Shot 036 --- Fired solid gold pellet, but neither Darren nor Jim Terry sees any sign of it. Because of the greatly increased pellet mass, Darren is not sure how long the pellets should take to hit the plasma. Next (and last) shot: since the solid gold pellet timing is not known well enough, make the next shot a normal, non-disruptive, plasma, and fire the gold pellets at 0.7 s.
Mar 29 1995 05:05:13:790PM	950329036	Robert Granetz	Shot 036 --- Fired solid gold pellet, but neither Darren nor Jim Terry sees any sign of it. Because of the greatly increased pellet mass, Darren is not sure how long the pellets should take to hit the plasma. Next (and last) shot: since the solid gold pellet timing is not known well enough, make the next shot a normal, non-disruptive, plasma, and fire the gold pellets at 0.7 s.
Mar 29 1995 05:05:28:410PM	950329037	Robert Granetz	Shot 037 --- Plasma, but no disruption. There were one or two small injections of something, but the pellet tracker sees it stop at R=80 cm, so it wasn't a macroscopic gold pellet. No macroscopic effect on the plasma. There was also a large (moly?) injection at 0.78 s. End of run

Physics Operator Comments
Mar 29 1995 07:55:56:990AM		John Goetz	Run plan for 950329 0830 - 1000 EST Load shot 950328025 make sure this shot runs tune up the RF 1000 - 1300 EST transfer control to LLNL RES continue MP from 950328
Mar 29 1995 08:00:08:520AM		John Goetz	1300 - 1700 EST Run MP097 Start from shot 950321022 VDE's can be initiated at a fixed, repeatable time by turning off the ZCUR PID gains at some point during the flattop. After a few shots, it will be possible to determine the vertical motion of the plasma as a function of time and measure quench times, halo currents, etc, and to see how repeatable these are. Then enable the LPI, and set its trigger so that the pellet will hit the plasma after it has moved a given distance down... 5 cm seems reasonable. The pellets can be easily doped with small chips of metal. For this run, we will use 50-100 $\mu$g of gold, which should give about 50 MW of radiation, effectively getting rid of all thethermal energy in $\le1$ ms. (For spectroscopic diagnostic purposes, it would be desirable to use something that doesn't occur naturally in the plasma).
Mar 29 1995 08:01:20:620AM		John Goetz	1300 - 1700 EST Two different lithium pellet sizes should be available. Measurements to be made include pellet speed, penetration distance, $\Delta n_e/n_e$, $T_e$, $P_{\rm rad}$, as well as the disruption characteristics already mentioned. Filament reconstructions will show how far the plasma moves, and particular attention should be paid to the vertical array of Rogowski segments on the inboard wall.
Mar 29 1995 08:38:06:720AM	950329001	John Goetz	1300 - 1700 EST Shot 950329001 Two hours of ECDC in D2 prior to run Enable A_SIDE fill and puff P_0 = 2.0e-5 Results: fizzle breakdown was late - some radial field CII signal > .004
Mar 29 1995 08:49:21:710AM	950329002	John Goetz	1300 - 1700 EST Shot 950329002 offset on BR_0 = 6.5e-3 Results: Plasma - disr. @ 0.89 breakdown earlier - still some radial field, but better vertical oscillation beginning at 0.82 natural moly injection @ 0.52
Mar 29 1995 09:02:53:700AM	950329003	John Goetz	1300 - 1700 EST Shot 950329003 P_0 = 1.8e-5 Results: fizzle - breakdown is on the inside fields are as good as usual CII signal ~ .004
Mar 29 1995 09:15:59:050AM	950329004	John Goetz	1300 - 1700 EST Shot 950329004 P_0 = 1.6e-5 and try again Results: plasma - disr. @ 1.01 z-oscillation begins @ 0.92 RF ~ 0.9MW EF2U on the rail late in shot
Mar 29 1995 09:31:23:290AM	950329005	John Goetz	1300 - 1700 EST Shot 950329005 RXU = -.015 @ 1.0sec ( was -.022) ZXL P gain = 2 @ 0.85 Results: fizzle - breakdown later than 004 but still acceptable CII light ~ .004
Mar 29 1995 09:41:07:500AM	950329006	John Goetz	1300 - 1700 EST Shot 950329006 IC_EF4 = -1085A (try and keep the Bz out a little longer) Results: plasma - disr. @ 0.96 EF@U on rail beginning @ 0.93
Mar 29 1995 09:55:19:980AM	950329007	John Goetz	Shot 950329007: RXU = 0 @ 1.0sec ZXU P gain = 6 for most of shot Results: plasma - disr. @ 0.90 EF2U not on the rail EF1's at voltage limit @ 0.75; only ZXU uncontrolled vertical oscillation @ 0.80
Mar 29 1995 10:05:18:270AM	950329008	John Goetz	Shot 950329008: ZXU = 0.03 for most of shot to help EF1U Results: plasma - disr. @ 0.57 moly injection @ 0.20
Mar 29 1995 10:21:20:410AM	950329009	John Goetz	Shot 950329009: NL_04 = 1e20 RF off; divertor gas puff off Results: plasma - all the way down almost didn't make it into ramp-down vert. osc. @ 0.95
Mar 29 1995 10:37:07:530AM	950329010	John Goetz	Shot 950329010: IC_EF4 = 2500A until 1.0sec slowdown CLEARIN ramp in Results: plasma - all the way down no vertical oscillation EF1 voltages and EF2 currents are o.k.; looks like the EF4 change did the trick
Mar 29 1995 10:57:25:640AM	950329011	John Goetz	Shot 950329011: stairstep off the FSP and STRKPSI gains at rampdown Results: plasma - all the way down still a slight mismatch across the ramp-down
Mar 29 1995 11:10:01:890AM	950329012	John Goetz	Shot 950329012: RCUR=.6545 late in shot to keep elongation down Results: plasma - all the way down chopper thrash at ramp-down reduced >1.2MW of RF
Mar 29 1995 01:07:58:510PM	950329020	John Goetz	Shot 950329020: grab control back from LLNL RES load shot 950329012 Results: Plasma - all the way down good starting point for MP097
Mar 29 1995 01:19:57:600PM	950329021	John Goetz	Shot 950329021: zero PID gains on ZCUR(2) and ZCUR(3) @ 0.7sec Results: plasma - disrupted @ 0.718
Mar 29 1995 01:39:01:690PM	950329022	John Goetz	Shot 950329022: no changes Results: plasma - disrupts @ 0.720 plasma @ z=-.034m @ 0.713sec
Mar 29 1995 01:50:28:550PM	950329023	John Goetz	Shot 950329023: fire large Li pellet to arrive at plasma center at 0.710 Results: plasma - disrupts @ 0.7175 spectroscopic signals turn over well before the disruption the pellet didn't seem to kill it
Mar 29 1995 02:03:47:600PM	950329024	John Goetz	Shot 950329024: fire large Li pellet to arrive at plasma center at 0.710 but with more gold Results: plasma - disrupts @ 0.717 still moves all the way to the bottom of the machine
Mar 29 1995 02:13:26:650PM	950329025	John Goetz	Shot 950329025: small Li pellet - 100 microgram of Au Results: plasma - disrupts @ 0.716 still hits the bottom of the machine
Mar 29 1995 02:29:03:140PM	950329026	John Goetz	Shot 950329026: NL_04 = 0.6e20 (get higher temp) Results: plasma - disrupts @ .712 faster disruption, but still goes all the way down
Mar 29 1995 02:30:13:600PM	950329027	John Goetz	Shot 950329027: no changes Results: plasma - disrupts @ .711 fastest disruption yet pellet was vary fragmented
Mar 29 1995 02:37:50:940PM	950329028	John Goetz	Shot 950329028: no changes Results: plasma - disrupts @ 0.712
Mar 29 1995 02:48:22:540PM	950329029	John Goetz	Shot 950329029: baseline - no Li pellets Results: plasma - disrupts @ 0.7145 natural Mo injection @ 0.68 (ruins baseline)
Mar 29 1995 03:06:13:180PM	950329030	John Goetz	Shot 950329030: repeat 029 Results: plasma - disrupts @ 0.714 good baseline - looks like the pellets take .002sec off the life of the plasma
Mar 29 1995 03:16:11:600PM	950329031	John Goetz	Shot 950329031: fire medium Li pellet (no Au) for a different kind of background Results: plasma - disrupts @ 0.7145 -> Au makes a difference of ~.002sec in disruption duration but the plasma still hits the bottom
Mar 29 1995 03:30:06:720PM	950329032	John Goetz	Shot 950329032: use impurity injector to inject tungsten @ 0.707 Results: plasma - disrupts @ .716 tungsten doesn't seem to work very quickly
Mar 29 1995 04:13:43:390PM	950329033	John Goetz	Shot 950329033: load solid gold pellets but don't fire Results: plasma - disrupts @ 0.43 killer hard x-ray shot - saturated from 0.1 until disruption
Mar 29 1995 04:27:13:170PM	950329034	John Goetz	Shot 950329034: P_0 = 1.9e-5 Results: plasma - disruption @ 0.53 no sign of hards very large Mo injection @ 0.50 killed this one
Mar 29 1995 04:35:47:230PM	950329035	John Goetz	Shot 950329035: no changes Results: plasma - disrupts @ 0.719 (new baseline) a hint of hards - breakdown moves out
Mar 29 1995 04:50:32:420PM	950329036	John Goetz	Shot 950329036: enable solid gold pellets P_0 = 2.1e-5 Results: plasma - disr. @ 0.717 unknown if any of the Au pellet got in
Mar 29 1995 05:10:30:420PM	950329037	John Goetz	Shot 950329037: tune PID gains for ZCUR(2) & (3) back on let the AuPI fire away Results: plasma - all the way down no signs of an Au pellet natural Mo injection at 0.78?

Engineering Operator Comments
Shot	Time	Type	Status	Comment
1	08:29:06:900AM	Plasma	Ok	no faults
2	08:38:55:630AM	Plasma	Ok	no faults
3	08:55:26:620AM	Plasma	Ok	no faults
4	09:03:57:360AM	Plasma	Ok	no faults
5	09:20:43:950AM	Plasma	Ok	no faults
6	09:31:59:060AM	Plasma	Ok	no faults
7	09:43:12:370AM	Plasma	Ok	no faults
8	09:55:42:070AM	Plasma	Ok	no faults
9	10:05:36:160AM	Plasma	Ok	no faults
10	10:21:19:810AM	Plasma	Ok	no faults
11	10:42:48:370AM	Plasma	Ok	no faults
12	11:03:16:880AM	Plasma	Ok	no faults
13	11:20:57:900AM	Plasma	Ok	no faults
14	11:33:54:520AM	Plasma	Ok	no faults
15	11:50:35:750AM	Plasma	Ok	no faults
16	12:04:51:800PM	Plasma	Ok	no faults
17	12:16:50:180PM	Plasma	Ok	no faults
18	12:33:36:610PM	Plasma	Ok	no faults
19	12:50:15:860PM	Plasma	Ok	no faults
20	01:00:25:200PM	Plasma	Ok	no faults
21	01:12:08:030PM	Plasma	Ok	No Faults.
22	01:28:59:310PM	Plasma	Ok	No Faults
23	01:40:23:590PM	Plasma	Ok	No Faults
24	01:52:34:450PM	Plasma	Ok	No Faults.
25	02:03:57:400PM	Plasma	Ok	No Faults.
26	02:14:23:160PM	Plasma	Ok	No faults.
27	02:24:30:390PM	Plasma	Ok	No Faults.
28	02:33:08:830PM	Plasma	Ok	No Faults.
29	02:42:33:490PM	Plasma	Ok	No Faults.
30	02:58:53:350PM	Plasma	Ok	No Faults.
31	03:10:05:870PM	Plasma	Ok	No Faults.
32	03:22:07:020PM	Plasma	Ok	No faults.
33	04:08:26:480PM	Plasma	Ok	No Faults.
34	04:18:09:650PM	Plasma	Ok	No Faults.
35	04:27:52:700PM	Plasma	Ok	No Faults.
36	04:37:56:280PM	Plasma	Ok	No Faults.
37	04:51:35:050PM	Plasma	Ok	No Faults.