Miniproposals

Miniproposal: 080 Date Filed: 1/20/1995 Title: Effect of Separatrix strike point location on divertor detachment First Author: Bruce Lipschultz Session Leader: Bruce Lipschultz (shots 1-27)

Engineering Operator Run Comment

strikepoint/silva/bertolino

Session Leader Plans

Physics Operators Plans

Session Leader Summaries

Entered: Jul 7 2004 03:49:12:117PM

Author: To Be Determined

run 950131 Engineering operator: F. Silva/V. Bertolino Physics operator: S. Wolfe Session leader: BLip Mini-proposal #81: Effect of Separatrix strike point location on divertor detachment One aspect of divertor detachment not systematically investigated is the 'radial' extent of detachment; the distance, referenced to the midplane, of the point in the SOL where pressure is no longer constant along a flux surface. We would like to investigate the dependence of this quantity on strike point location. This work will be part of the milestone \#52 - comparison of the slot, open and inclined plate divertor geometries. During this run we located the strike point at different locations on the inclined plate and slot and ramped the plasma denaity over a range that included detachment. This was a very successful run operationally - we were able to achieve the control of strike point location and density needed to fulfill this mp. This is a tribute to the controllers and to Steve's use of them. To summarize the physics results after first look at the data, the detachment threshold at the separatrix does not seem to vary much as the strike point location is varied from up the divertor plate to probe location 7. Looking at the constant density shots (nebar=2.1e20) at each separatrix location, slot and strike point on probe 1 had detachment through rho=2.5 mm. For the other strike points there was no obvious indication of detachment. For density ramps detachment at the separatrix appears independent of strike point location below the nose (nebar ~ 1.7e20). The differences between strike point locations comes primarily from the rise in density required to detach through probe 7. CLearly less density rise is needed the closer the strike point location is to the nose of the divertor. We will have to look more closely at the FSP data to determine when either probe 8 or 9 show indications of plasma detachment. The extent of detachment does appear to increase with density as seen before. The increase in extent appears to be hard to quantify with the ramping density. In view of the differences between constant density shots and density ramp shots it is questionable whether to remain with a density ramp for determining detachment thresholds. Below find a quick summary of the different strike point location data. Without having seen the pressure profiles from the fast-scanning probe I cannot definitively say out to what point in the SOL the plasma is detached. For the purposes of this summary I will rely on looking at where the peak in the pressure profile is at the divertor using the divertor probes. Slot Divertor: shots 2-11 localized detachment on probes 1-3 (rho=2.5-5 mm at nebar=1.7-2.1e20) depending on the shot. at nebar= 2.5e20 (shot 10) deatchment appears to extend out to probe 6 (rho=7 mm). at nebar=2.9e20 (same shot) it appears to have reached probe 7. at nebar=2.1e20 (shot 11 constant density) detachment at probe 1 only. Strike point at probe 1 (bottom of divertor): shots 12-16 localized detachment maybe at separatrix in shot 12. Densities in the 1.6-1.7e20 range. shot 14 - detachment at probe 1 at nebar=2.1e20, probe 2 @ nebar=2.2e20, probe 3 @ nebar=2.3e20, probe 4 @ nebar=2.3e20, probe 5 @ nebar=2.2e20, probe 6 (rho=5 mm) around 2.4e20. The detachment may extend further. We may have had detachment through probe 8 in shot 15. For the constant density shot (nebar=2.1e20) detachment through probe 3 (rho=2.5 mm). Strike point at probe 4: shots 17-21 shot 19 - detachment at probes 1-4 at nebar=1.6e20 (rho~0), probe 5 (rho=1.5 mm) at nebar=1.7-2e20, probes 6&7 (rho=3.5 mm) @ nebar= 2.1e20. shot 20 - detachment through probe 8 (rho=6mm) possibly at nebar=2.5e20 shot 21 - constant density - there may not be any detachment. Strike point on probe 7: shots 22-26 detachment at probe 7 at nebar = 1.8-2e20. detachment at probe 8 (rho=4 mm) at nebar~ 2.5e20. constant density shot - no detachment strike point on probe 8: shot 27, there may have been some detachment in the SOL for nebar~2.5e20. The following is the shot summary. shot 1: Tuesday test shot 2: Great start. nl04 ramping from .7 to 1.1 e20. Strike point in the slot and roughly cnstant. Local detachment up to probe 1 (rho=2.5 mm). For the next shot Steve will try to hold the strike point more constant. Ar will be on, RF on, Mo monitor on... shot 3: The strike point position is much more constant for this shot. We achieve the same local detachment on probe 1 (now rho=4mm) at about 900 ms. The FSP went in 3 times but didn't quite reach the separatrix. We will make some more minor adjustments in the location o fthe strike point (closer to probe 1) and the plasma (closer to the FSP). shot 4: Slight improvement to get the slot strike point where we wanted it (rho=2.5 mm at probe 1). Same local detachment on probe 1 as seen on the previous shots. We will send the probe in fully the next shot. shot 5: All went fine, same as previous shots. Change density ramp for next shot. He went in through B-side upper last shot to simultaneously look at He and Ar penetration for these shots. shot 6: disruption at .7 sec due to vertical instability. Retry. shot 7: Higher density this shot; nl04 ramping from .9 to 1.5e20. Nebar from 1.6 - 2.4e20. Localized detachment occurs up through probe 5. Next shot the same with probe scans. shot 8: Same as previous shots. Still waiting for good probe scan. One more shot at this density. shot 9: Probe scan fine. Move on to higher density ramp. shot 10: Probe scan fine. Next shot constant density of nl04=1.1e20. shot 11: Nice constant density at nl04=1.1e20 *nebar=2.2e20). Probe scanned to within 3 mm of separatrix. Local detachment at probe 1 (rho=2.5 mm) over almost all the shot. shot 12: This shot was fine for separatrix location on probe 1. nl04 ramping from .6 to 1.e20 (nebar from 1.3 - 1.7e20). The FSP probe didn't go in this shot so we will repeat it. The rf pilse at .9 sec heats the divertor - the pressure stays constant but Te goes up and ne down over most the SOL except withing several mm of the separatrix. shot 13: same as 12 but with scanning probe. shot 14: medium density ramp, nl04 = 1-1.5 e20 and scanning probe all right. Next shot the highest density ramp. shot 15: High density ramp, nl04 up to 1.8e20 (nebar=2 -3 e20). Probe scan fine. Next shot constant density - nl04=1.1e20. shot 16: Constant density at nl04=1.1e20 (nebar= 2.e20). Looks like we got localized detachment up into the probe 4 region. I won't know until we get the processed data. Also, no ECE this shot due to turbo tripout. shot 17: Looks pretty good, separatrix on probe 4, density ramp over low range (0.5-1.0 in nl04). Mo injection at ~ .64 sec with no large effect in divertor. no detachment. shot 18: same as shot 17 with probe scan. We apparently have a problem with hard x-rays last shot and this one. Move on to medium density ramp the next shot shot 19: mid-density ramp, nl04=1. - 1.6e20 on this shot with probe making it. Odd behaviour looking at the outer divertor Isat footprint. There does appear to be some localized detachment around probe 4 but it is not clear without the processed data what the extent is. shot 20: high density ramp. Definite detachment up through probe 7. shot 21: constant density shot nl04=1.1e20 with strike point on probe 4. shot 22: switch to strike point on probe 7 and low-density ramp. Probe not scanned on this shot. Hard x-rays evident. No obvious detachment. shot 23: Second shot with low density ramp. Everything fine except for injection shortly before .9 sec. We will go on and switch to medium density ramp for the next shot. shot 24: medium density ramp. Probe went in just fine. There may possibly be detachment on probe 7 starting at .6 sec. shot 25: high density ramp. Probe went in fine. Dtachment on probe 7 and possibly on probe 8 as well. shot 26: constant density shot for separatrix on probe 7. looks fine. Probe 7 doesn't look detached but we will have to look at the processed data. shot 27: We switched to flat-plate divertor. Steve has boldly decided to use STRKPSI to sweep the separatrix across probe 8. This seems to have worked very well. In fact he was able to program the sweep across probe 8 and back again! Unfortunately when we set up the shot we forgot to use constant density so that there is a density ramp during the sweep. The probe did not get inserted but the flux surfaces would have been in the right place for a scan if we had another shot.

Physics Operator Summaries

Entered: Jul 7 2004 04:36:53:050PM

Author: To Be Determined

Physics Operator's Summary 950131 MP#080 Effect of Separatrix strike point location on divertor detachment SL: Blip PO: Wolfe EO: Silva/Bertolino The idea of this run was to start from a slot equilibrium and march the strikepoint up the outer divertor plate, taking a series of shots with different density programming at each condition. Principal diagnostics were the domed probes and the FSP. The equilibrium had to be tweaked to make sure it was reachable with the probe. Piggyback experiments included impurity screening (He and Ar), and ICRF; the ICRF loop arrangement on the E-port antenna had been returned to its former configuration (circa the 1/18 successful operation). Overall, the run was successful. Most of the desired strikepoint locations were surveyed; He and Ar puffing were done routinely from shot 5 on, and "interesting" results were obtained; and the RF boys got both antennas up to good power levels, despite having to re-tune frequently as we kept changing the target density on them. From the operational standpoint, this run was a good demonstration of the use of different reference points for STRKPSI control. This technique seems to be more robust than programming a fixed non-zero rho displacement for the standard reference point. Even a quasi-flat-plate swept strike case was managed using STRKPSI control instead of x-point control. The initial equilibrium requested was a slot divertor, like 950131028, at 800kA, with probe 1 held as close as possible to constant rho. This was accomplished by putting a second STRKPSI on wire 12, with the reference points RSOUT and ZSOUT set to the probe 1 coordinates (.626,-.552). I also re-ran the controller algorithm for this wire with the same choice of (RSOUT,ZSOUT), but since the shape of the resulting controller was essentially unchanged from the standard I did not re-do that calculation for subsequent cases. This configuration was set up on shots#2-8, getting the rho value right and setting up the gaps and height for the FSP. Acceptable data on shots 7-11 with different density programming. On shot 8, and thereafter, the P gain on RXL was changed to 25(Physics gain), from 12, making the RXL more constrained than ZXL. Shot 12 moved the strikepoint onto probe 1 (same ref, STRKSPI=0. all the way across). Good data 12-16 (FSP not in on 12). The high density ramp case disrupts in rampdown every time, but the halos aren't bad. I tried some tweaking of the rampdown all through the day (see Logbook) but basically couldn't get rid of it; most are density limit disruptions. Shot 17-21 moved the reference to probe 4 (rsout=.6197, zsout=-.5115) Tweaked the RXL to move the x-point out. Made some changes to get rid of a density thrash and early hards on the low-density case. Shot 22-26 moved reference to between probes 7 and 6 (0.612,-0.46240). This time, based on Brian's FSP prediction, programmed a ramp on RXL to keep the target at the FSP radius close to constant. Still had some hards on the first low density case, which also had a bouncy startup, so I raised the fill to 1.7e-5 (had been 1.5); I think what's changing is the wall condition. Shot 27 was set up to try sweeping the strike across probe 8 and back, using STRKPSI with reference at the probe 8 coordinates (.6145,-.4367). RXL was programmed by guesswork to be near 0. The density was programmed for the high density ramp (a mistake, since we didn't really want to both sweep the strike and ramp the density, but it was getting late.) The FSP was not fired, in hopes we would get another shot, which we didn't. Amazingly, this prescription worked. The strike went back and forth and part way back out again between .5 and 1 sec. It might have done even better with less integral gain, but it was pretty much what was asked for. The target was easily accessible to the FSP, probably could have been moved up some. Problems: -------- The run got off to a bit of a late start because the Alternator PC had packed it in. The problem was traced to a bad video card, which was replaced. There was another PC network problem which affected the CRYO readouts on the mimic board for the first few shots. This was fixed without any resulting delay. On shot 5, the gas programming for PULSE_GAS_2 didn't load the first time after I thought I had ok'd the screen. Fortunately, I checked and redid it so the shot loaded ok. This seems to be another ghost, but could have been operator error; no witnesses. I reduced the P gain on the slow ZCUR wire from 3 to 1.5 in rampdown to stop the OH2's from crowbarring in rampdown disruptions. It should be possible to drop this to 1.5 for the whole shot, but the one time I tried it, along with a dozen other changes, I got a full current disruption at 0.65 sec, so I put it back. There were lots of traces programmed to start into a ramp-down sequence at times between .9 and 1 sec. I ended up moving all of these except the NL_04 back out to 1 sec or later. It didn't seem to hurt. The CLEARIN ramp at the end of the shot floors the EF2's, often abetting a disruption. I delayed and slowed this, but didn't go far enough to get rid of it. The RCUR program still doesn't have the offset in it, so there's still an jump and thrash at segment switch. I should have re-calculated the predictor and determined a new offset, if any, but by the time I thought of it it would have cost useful shots. There were several shots with hards and bouncy startups later in the run. Raising the fill to 1.7e-5 seemed to help. I suspect wall (de-)conditioning. Once again IGOR seemed to be taking longer late in the run. This may be a population problem (more people, more scopes), but it occurs to me that one or more servers might be experiencing a memory leak. It might be helpful for TomandJosh to look into restarting all the servers around 1-2PM to see if it helps at all. Scorecard: ---------- Tests 1 Plasmas 26 Duds 0 Fizzles 0 ------- -- Total 27

Session Leader Comments
Jan 31 1995 09:06:06:790AM		Bruce Lipschultz	run 950131 Engineering operator: F. Silva Physics operator: S. Wolfe Session leader: BLip Mini-proposal #81: Effect of Separatrix strike point location on divertor detac One aspect of divertor detachment not systematically investigated is the 'radial' extent of detachment; the distance, referenced to the midplane, of the point in the SOL where pressure is no longer constant along a flux surface. We would like to investigate the dependence of this quantity on strike point location. This work will be part of the milestone \#52 - comparison of the slot, open and inclined plate divertor geometries. During this run we will locate the strike point at different locations on the inclined plate and slot and ramp the plasma denaity over a range i including detachment.
Jan 31 1995 09:35:47:300AM	950131002	Bruce Lipschultz	shot 2: Great start. nl04 ramping from .7 to 1.1 e20. Strike point in the slot and roughly cnstant. Local detachment up to probe 1 (rho=2.5 mm). For the next shot Steve will try to hold the strike point more constant. Ar will be on, RF on, Mo monitor on...
Jan 31 1995 10:06:26:230AM	950131003	Bruce Lipschultz	shot 3: The strike point position is much more constant for this shot. We achieve the same local detachment on probe 1 (now rho=4mm) at about 900 ms. The FSP went in 3 times but didn't quite reach the separatrix. We will make some more minor adjustments in the location o fthe strike point (closer to probe 1) and the plasma (closer to the FSP).
Jan 31 1995 10:24:51:660AM	950131004	Bruce Lipschultz	shot 4: Slight improvement to getthe slot strike point where we wanted it (rho=2.5 mm at probe 1). Same local detachment on probe 1 as seen on the previous shots. We will send the probe in fully the next shot.
Jan 31 1995 10:39:02:370AM	950131005	Bruce Lipschultz	shot 5: All went fine, same as previous shots. Change density ramp for next shot. He went in through B-side upper last shot to simultaneously look at He and Ar penetration for these shots.
Jan 31 1995 11:04:07:640AM	950131006	Bruce Lipschultz	shot 6: disruption at .7 sec due to vertical instability. Retry.
Jan 31 1995 11:27:12:240AM	950131007	Bruce Lipschultz	shot 7: Higher density this shot; nl04 ramping from .9 to 1.5e20. Nebar from 1.6 - 2.4e20. Localized detachment occurs up through probe 5. Next shot the same with probe scans.
Jan 31 1995 11:42:11:890AM	950131008	Bruce Lipschultz	shot 8: Same as previous shots. Still waiting for good probe scan. One more shot at this density.
Jan 31 1995 11:44:21:960AM	950131008	Bruce Lipschultz	shot 8: Same as previous shots. Still waiting for good probe scan. One more shot at this density.
Jan 31 1995 12:04:41:400PM	950131009	Bruce Lipschultz	shot 9: Probe scan fine. Move on to higher density ramp.
Jan 31 1995 12:24:10:690PM	950131010	Bruce Lipschultz	shot 10: Probe scan fine. Next shot constant density of nl04=1.1e20.
Jan 31 1995 12:41:37:390PM	950131011	Bruce Lipschultz	shot 11: Nice constant density at nl04=1.1e20 *nebar=2.2e20). Probe scanned to within 3 mm of separatrix. Local detachment at probe 1 (rho=2.5 mm) over almost all the shot.
Jan 31 1995 01:15:22:410PM	950131012	Bruce Lipschultz	shot 12: This shot was fine for separatrix location on probe 1. The FSP probe didn't go in this shot so we will repeat it. The rf pilse at .9 sec heats the divertor - the pressure stays constant but Te goes up and ne down over most the SOL except withing several mm of the separatrix.
Jan 31 1995 01:21:05:040PM	950131013	Bruce Lipschultz	shot 13: same as 12 but with scanning probe.
Jan 31 1995 01:49:31:550PM	950131014	Bruce Lipschultz	shot 14: medium density ramp, nl04 = 1-1.5 e20 and scanning probe all right. Next shot the highest density ramp.
Jan 31 1995 01:54:42:950PM	950131015	Bruce Lipschultz	shot 15: High density ramp, nl04 up to 1.8e20 (nebar=2 -3 e20). Probe scan fine. Next shot constant density - nl04=1.1e20.
Jan 31 1995 02:06:06:850PM	950131016	Bruce Lipschultz	shot 16: Constant density at nl04=1.1e20 (nebar= 2.e20). Looks like we got localized detachment up into the probe 4 region. I won't know until we get the processed data. Also, no ECE this shot due to turbo tripout.
Jan 31 1995 02:06:37:850PM	950131016	Bruce Lipschultz	shot 16: Constant density at nl04=1.1e20 (nebar= 2.e20). Looks like we got localized detachment up into the probe 4 region. I won't know until we get the processed data. Also, no ECE this shot due to turbo tripout.
Jan 31 1995 02:29:59:270PM	950131017	Bruce Lipschultz	shot 17: Looks pretty good, separatrix on probe 4, density ramp over low range (0.5-1.0 in nl04). Mo injection at ~ .64 sec with no large effect in divertor. no detachment.
Jan 31 1995 02:46:11:940PM	950131018	Bruce Lipschultz	shot 18: same as shot 17 with probe scan. We apparently have a problem with hard x-rays last shot and this one. Move on to medium density ramp the next shot.
Jan 31 1995 03:13:46:120PM	950131020	Bruce Lipschultz	shot 20: high density ramp. Definite detachment up through probe 7.
Jan 31 1995 03:27:33:870PM	950131021	Bruce Lipschultz	shot 21: constant density shot nl04=1.1e20 with strike point on probe 4.
Jan 31 1995 03:55:56:980PM	950131022	Bruce Lipschultz	shot 22: switch to strike point on probe 7 and low-density ramp. Probe not scanned on this shot. Hard x-rays evident.
Jan 31 1995 04:01:51:950PM	950131022	Bruce Lipschultz	shot 22: switch to strike point on probe 7 and low-density ramp. Probe not scanned on this shot. Hard x-rays evident. No obvious detachment.
Jan 31 1995 04:15:58:420PM	950131023	Bruce Lipschultz	shot 23: Second shot with low density ramp. Everything fine except for injection shortly before .9 sec. We will go on and switch to medium density ramp for the next shot.
Jan 31 1995 04:21:43:340PM	950131024	Bruce Lipschultz	shot 24: medium density ramp. Probe went in just fine. There may possibly be detachment on probe 7 starting at .6 sec.
Jan 31 1995 05:03:44:060PM	950131025	Bruce Lipschultz	shot 25: high density ramp. Probe went in fine.
Jan 31 1995 05:07:48:090PM	950131026	Bruce Lipschultz	shot 26: constant density shot for separatrix on probe 7. looks fine. Probe 7 doesn't look detached but we will have to look at the processed data.
Jan 31 1995 06:12:27:090PM	950131027	Bruce Lipschultz	shot 27: We switched to flat-plate divertor. Steve has boldly decided to use STRKPSI to sweep the separatrix across probe 8. This seems to have worked very well. In fact he was able to program the sweep across probe 8 and back again! Unfortunately when we set up the shot we forgot to use constant density so that there is a density ramp during the sweep. The probe did not get inserted but the flux surfaces would have been in the right place for a scan if we had another shot.

Physics Operator Comments
Jan 31 1995 07:20:57:300AM		Steve Wolfe	Run 950131 MP #080 SL: BLIP PO: Wolfe EO: Silva This run will be basically a strikepoint location scan, with density ramps, to determine the detachment effects of geometry. Start from 950127028, with current set to 800kA and nl04 ramping from 0.7 to 1.2e30 over the period .45 to .95 sec. Set up a STRKPSI on wire 12 with rsout=.626,zsout=-.552 (location of probe 1), but no gains on to start. Will try using moving reference rather than funny STRKSPI programing to get Bruce what he wants.
Jan 31 1995 07:37:29:980AM		Steve Wolfe	Run 950131 Note on STRKPSI: changing the reference point on the controller has essentially no effect on the controller. I'm a bit surprised, because the controller is called with a non-full rank set in ALL.
Jan 31 1995 09:00:15:700AM	950131001	Steve Wolfe	Shot #950131001 Standard Tuesday OH test. We are running a bit late getting started because the Alternator PC was gronked. Video board replaced; now ok. Test ran ok; we seem to have no voice announcements, and the MIMIC board readout for CRYO isn't there.
Jan 31 1995 09:24:02:560AM	950131002	Steve Wolfe	Shot #950131002 Try for plasma; set up as noted in RUN- 800ka version of 950127028. Ran ok. Breakdown looks good. Wire 12 strkpsi (ref at probe 1) is ramping from 0 to 1500 between 0.4 and 1.0sec Bruce likes it at 0.8 sec.
Jan 31 1995 09:50:31:810AM	950131003	Steve Wolfe	Shot #950131003 GO to wire 12 strkpsi, programmed for -.002 (old was -.0025) Change density programming for falt until .5 sec CHange RCUR in by 2mm Delay CLEARIN integral gain until .36 sec Note: I turned off the gains on wire 9, but it didn't go to lower case. Ar puff on this shot. RF at 0.9 sec. Ran ok- got a crowbar on the PF. Vertical problem at 0.87, but ramped down ok to 1.33 sec, 300kA. The glitch is where the E-port antenna turns off, looks like a glitch on all the hybrid Aouts. Bruce says the probe 1 is at -4mm insterad of -2mm. Also, Brian can't reach the LCFS yet.
Jan 31 1995 10:14:50:600AM	950131004	Steve Wolfe	Shot #950131004 GO to wire 12 strkpsi, programmed for -.0015 MOve RXL out from -.0194 to -.018 Drop ZCUR from -.015 to -.018 CLEARIN gain didn't go in last shot, try again. (Is this a new ghost or did I lose it when I reloaded): Delay CLEARIN integral gain to .36 sec Ran ok gaps are smaller. Brian likes the height. Bruce seems to like the strike?
Jan 31 1995 10:30:36:890AM	950131005	Steve Wolfe	Shot #950131005 Load a gas pulse (B-side upper) 20msec wide He pulse at 0.5 sec for Garry. I had to do this twice, it didn't show up the first time. For next shot, reduce slow ZCUR P-gain from 3 to 1.5 to try to avoid crowbar on rampdown. Getting disruptions on rampdown, still.
Jan 31 1995 10:59:47:690AM	950131006	Steve Wolfe	Shot #950131006 For next shot, reduce slow ZCUR P-gain from 3 to 1.5 to try to avoid crowbar on rampdown. Increase CLEARIN integral gain from 2.0 to 4.0 Move RCUR in from .655 to .653 Move CLEARIN from -.005 to -.002 Change density ramp to 1.0 to 1.6 Slow down current rampdown. Disrupted half-way through (0.65)! That was a bad one. Railed ef2U early, then get a veritcal mode as it comes down. That one got in trouble early, something happens at 0.329 - density goes berserk.
Jan 31 1995 11:15:38:160AM	950131007	Steve Wolfe	Shot #950131007 Change slow ZCUR P-gain back to 3 from 1.5 Slow down density increase, still ramp to 1.0 to 1.6 Made it through, marfe at thge end. Still crowbarring on rampdown. The EF2s are now much lower early, floor on rampdown. EFCs are trying to hold the vertical position on rampdown. For next shot, drop slow ZCUR p-gain to 1.5 at 1.2 sec, still trying to stop the crowbar. Brian says its further away.
Jan 31 1995 11:39:14:690AM	950131008	Steve Wolfe	Shot #950131008 drop slow ZCUR p-gain to 1.5 at 1.2 sec, still trying to stop the crowbar. Reduce ZCUR from -1.8 to -2.1 INcrease RXL gain from 12 to 25 (Physics) Tweak ZXL and ZXU during rampdown. Ran ok, no crowbar. Little burst of vertical inst. .95 to 1.05sec RXL still moving in, only a little less than previous.
Jan 31 1995 11:53:33:840AM	950131009	Steve Wolfe	Shot #950131009 Drop strkpsi gain in rampdown. Delay and reduce RCUR rampin on rampdown. Disrupted on rampdown earlier.
Jan 31 1995 12:16:32:140PM	950131010	Steve Wolfe	Shot #950131010 INcrease density to 2.0 final density. Delay ZCUR ramp back to midplane until 1 sec, slow it down. Disrupted on early rampdown.
Jan 31 1995 12:29:52:410PM	950131011	Steve Wolfe	Shot #950131011 Hold density NL_04 constant at 1.1e20 Ran ok, disruption on ramp-down was later (1.35)
Jan 31 1995 12:59:18:750PM	950131012	Steve Wolfe	Shot #950131012 Move strikepoint onto plate (STRKPSI=0.) at probe 1 Ramp density from .6e20 to 1.0e20, beginning at .5 sec. Made it. Ramped all the way down 1.5 sec. The EF2's are still flooring just after rampdown. Bruce thinks strike is ok. Brian says ok too.
Jan 31 1995 01:11:16:090PM	950131013	Steve Wolfe	Shot #950131013 Repeat shot so Brian can get his FSP scans. Ran ok, looks the same.
Jan 31 1995 01:30:30:300PM	950131014	Steve Wolfe	Shot #950131014 INcrease density so ramp is 0.9 to 1.5 Extend EF4 current into rampdown, look for EF2 response. Disrupted at 1.27. EF2's are flooring at the same time, but the main effect seems to be density. The probe boys are happy; time to move on.
Jan 31 1995 01:48:01:590PM	950131015	Steve Wolfe	Shot #950131015 INcrease density so ramp is to 2.0 Disrupted early in ramp-down. Bruce says ok.
Jan 31 1995 01:54:15:200PM	950131016	Steve Wolfe	Shot #950131016 Flat density at 1.1 (reloaded wire from shot 11) ECE turbo tripped out. They're off for this shot. Ran fine. On to the next strike point.
Jan 31 1995 02:24:23:610PM	950131017	Steve Wolfe	Shot #950131017 MOve strkpsi reference to probe 4: rsout=.6197, zsout=-.5115 Move RXL from -.018 to -.015 density ramp from 0.6 to 1.0 again. Got some hards on that one. A little bounce on startup. PLenum pressure is down to 15.8; raise it for the next shot. Didn't get the full density ramp, injection at .64 sec. Early density burst causes low gas?
Jan 31 1995 02:36:30:740PM	950131018	Steve Wolfe	Shot #950131018 MOve strkpsi reference to probe 4: rsout=.6197, zsout=-.5115 Move RXL from -.018 to -.015 density ramp from 0.6 to 1.0 again. NO changes, see if the plenum pressure change does it. Seems better. Still a problem early.
Jan 31 1995 02:55:07:470PM	950131019	Steve Wolfe	Shot #950131019 Move RXL from -.015 to -.012 density ramp from 0.9 to 1.5 again. Change initial RCUR in SEG 2 from .645 to .64 to reduce thrash, keep it off the limiter. I should either put in the 10000 offset, or, better, recalculate the predictor, but that will lose the outer gap for a shot. Should have done it to begin with. That one looks nicer, no hards, breakdown is better (I didn't do thing that early.)
Jan 31 1995 03:13:22:940PM	950131020	Steve Wolfe	Shot #950131020 Go to high density ramp (to 2.0) No other changes; this one looked good, but I'm worried about that breakdown on 17,18. Ran, disrupted in rampdown (600kA) .
Jan 31 1995 03:20:54:220PM	950131021	Steve Wolfe	Shot #950131021 Go to flat density at 1.1e20 Ran, looked ok. On to the next strike point. .
Jan 31 1995 03:53:12:110PM	950131022	Steve Wolfe	Shot #950131022 Next strike point, near probe 7, 30% of way to probe 6 (0.612,-0.46240) density ramp from 0.6 to 1.0e20 Hards again! An early bouncer again. Must have something to do with the gas load from the previous shot. Brian says to move the x-point further out early
Jan 31 1995 04:07:32:170PM	950131023	Steve Wolfe	Shot #950131023 Raise fill to 1.7e-5 Change RXL program to -.009 early, ramping to -.012 (where it was). Ran ok. No bounce, no hards. Injection at 0.86sec Brian says perfect target.
Jan 31 1995 04:17:25:940PM	950131024	Steve Wolfe	Shot #950131024 Medium density ramp. No equilibrium changes. Disruption early in rampdown (1.16); got another crowbar.
Jan 31 1995 04:29:29:900PM	950131025	Steve Wolfe	Shot #950131025 High density ramp. Delay CLEARIN ramp at end of shot, make it more gentle. It did delay the EF2 floor, as expected, but still disrupted in rampdown at 1.15
Jan 31 1995 04:46:02:840PM	950131026	Steve Wolfe	Shot #950131026 Flat density case ok
Jan 31 1995 05:25:52:460PM	950131027	Steve Wolfe	Shot #950131027 Program sweeps back and forth around probe 8 on strkpsi Move RXL out High density ramp. Disrupted in early ramp-down. It looks like it sort of worked! It did work! Unfortunately, we don't get another shot for the FSP. Oh well, not a bad one to finish with.

Engineering Operator Comments
Shot	Time	Type	Status	Comment
1	08:49:10:220AM	Test	Ok	oh coax test
2	09:03:12:840AM	Plasma	Ok	no faults, plasma 09:05
3	09:37:04:930AM	Plasma	Ok	comm fault oh2 up after plasma
4	10:01:07:030AM	Plasma	Ok	comm fault oh2u, after plasma
5	10:23:51:960AM	Plasma	Ok	comm fault oh2u, after plasma
6	10:42:13:680AM	Plasma	Ok	comm fault ef1u, plasma disrupt
7	11:04:41:810AM	Plasma	Ok	comm fault oh2l, plasma
8	11:26:07:930AM	Plasma	Ok	no faults, plasma
9	11:45:34:880AM	Plasma	Ok	no faults, plasma
10	12:04:35:640PM	Plasma	Ok	no faults, plasma
11	12:24:16:250PM	Plasma	Ok	no faults, plasma
12	12:43:53:810PM	Plasma	Ok	no faylts, plasma
13	01:03:04:500PM	Plasma	Ok	no faults
14	01:19:39:160PM	Plasma	Ok	no faults
15	01:36:04:960PM	Plasma	Ok	no faults
16	01:51:19:290PM	Plasma	Ok	no faults
17	02:06:55:000PM	Plasma	Ok	no faults
18	02:26:34:840PM	Plasma	Ok	no faults
19	02:45:19:520PM	Plasma	Ok	no faults
20	03:02:51:830PM	Plasma	Ok	no faults
21	03:18:43:320PM	Plasma	Ok	no faults
22	03:34:27:910PM	Plasma	Ok	no faults
23	03:55:57:150PM	Plasma	Ok	no faults
24	04:10:04:480PM	Plasma	Ok	comm faults oh1, oh2u after disruption
25	04:24:09:010PM	Plasma	Ok	no faults
26	04:37:15:080PM	Plasma	Ok	no faults
27	04:53:43:660PM	Plasma	Ok	disruption induced comm faults