Miniproposals

Miniproposal: 227 Date Filed: 1/14/1999 Title: H-Mode Ion-Fueling Experiments First Author: Brian Labombard Session Leader: Brian Labombard (shots 1-11)

Miniproposal: 229 Date Filed: 1/13/1999 Title: Secondary Divertor Experiments First Author: Brian Labombard Session Leader: Brian Labombard (shots 12-27)

Engineering Operator Run Comment

MP#227,MP#229/Wolfe/LaBombard/Silva

Session Leader Plans

Physics Operators Plans

Session Leader Summaries

Entered: Jul 7 2004 03:49:19:570PM

Author: To Be Determined

Session Leader's summary of run 990226 MP#227 - H-Mode Ion-Fueling Experiments MP#229 - Secondary Divertor Experiments Physics Operator: Wolfe Session Leader: LaBombard The goal of this run was to execute miniproposals #227, "H-Mode Ion-Fueling Experiments" and #229, "Secondary Divertor Experiments". This goal was accomplished. The first half of the run (shots 1-11) focussed on "H-Mode Ion Fueling Experiments" while the remained of the run (shots 12-27) covered "Secondary Divertor Experiments". ________________________________________________________________________________ MP#227 - H-Mode Ion-Fueling Experiments During previous runs it has been observed that the lower divertor neutral pressure "pumps out" during the high dndt phase of an H-mode transition, particularly when the transition leads to an EDA H-mode. Apparently, the H-mode is fueled, at least in part, by neutrals in the lower divertor region. Question: Is the fueling simply from ionization of these neutrals above the x-point region inside the last-closed flux surface or does the fueling involve parallel plasma flows from the divertor to the core scrape-off layer? The goal today was to use the F-port and A-port scanning probes (FSP,ASP) which are outfitted with Mach probe sensors to look for changes in the parallel plasma flows during the high dndt phase of L to H-mode transitions. The FSP system worked very well today and most of the analysis will rely on these data. The new ASP also functioned extremely well mechanically. Unfortunately, a CAMAC problem rendered the data from the ASP system to be marginally useful. "Longitudinal parity error during read" of two Aurora 14 modules persisted whenever the voltage waveform into these units exceeded 4 volts peak-to-peak, a range well within the limits of these units. The problem persisted despite some intense effort to rectify it two days and nights before this run. Apparently the CAMAC crate power supply or back-bus is at fault. The crate will be replaced on the next maintenance day (monday). Setup: NL04 ~ 1.0, 0.8 MA, 5.3 tesla, RF ~ 1-1.2 MW starting around 0.8 sec Three scans of FSP and ASP - one around 0.65 sec (ohmic L-mode), one around high dndt phase of L-H transition (.85 sec), and one during RF-heated H-mode phase (1.05 sec). Shot#2,3: FSP firing. Optimizing timing with high dndt phase. Shot#4,5,6: Best FSP and ASP data at NL04 ~ 1.0 Setup: Change to NL04 ~ 1.2 Shot#7: Not quite NL04 ~1.2. FSP firing. Optimizing timing with high dndt phase. Shot#8,11: Best FSP and ASP data at NL04 ~ 1.2 (shots#9,10 -> fizzle) ________________________________________________________________________________ MP#229 - Secondary Divertor Experiments Recent analysis of flows into the divertor chamber and ionization in the main chamber indicate that most of the plasma in the main chamber recycles onto main chamber surfaces, i.e, the limiters, the walls, and the top surfaces of the lower divertor. Particle recycling fluxes in the lower divertor chamber are large but well separated from the particle recycling that occurs on the walls in main chamber. At first glance, this is not too surprizing since the closed lower divertor chamber is presently optimized for power flux handling not particle flux handling. However, it has also been found that cross-field particle transport radially increases with distance from the separatrix in the SOL. Thus, some questions arise, including: Can the upper divertor with its relatively open geometry be used to influence this main chamber and divertor recycling balance? Or, is the cross-field transport so high (relative to parallel flows to the divertor) as to maintain the same coupling between midplane neutral pressure and core plasma density, independent of divertor geometry? Some related questions are also of interest from an operations point of view: Are the neutral pressures in the upper divertor high enough for a cryopump to be used for density control? What is the relationship (if any) between neutral pressure in the upper divertor and SSEP? Is this relationship strong enough to allow dynamic control of particle throughput on a cryopump? In order to address these questions, a series of discharges where run today at principally two plasma densities (NL04 ~ 1.0, 0.8) and with varying upper secondary separatrix position (SSEP). The principal diagnostics were upper divertor, lower divertor, and midplane neutral pressures, and the F-port and A-port scanning probes (FSP,ASP) to monitor SOL plasma conditions and flows. Steve Wolfe did an excellent job of putting a controller together for SSEP. With a few practice shots, he demonstrated that he could essentially program whatever SSEP we wanted. For NL04 ~ 1.0, the upper divertor pressures were found to vary with SSEP from around 1 mtorr (SSEP > 15 mm) to 20 mtorr (SSEP ~ 0 mm). So we already have an answer to one of our questions: Yes, a cryopump in the upper divertor could be used for dynamic density control. Setup: Similar to first-half of run - NL04 ~ 1.0, 0.8 MA, 5.3 tesla, RF ~ 1-1.5 MW starting around 0.8 sec. Three scans of FSP and ASP - one around 0.65 sec (ohmic L-mode), one around high dndt phase of L-H transition (.85 sec), and one during RF-heated H-mode phase (1.05 sec). Shot#12: Testing SSEP controls: Upper diverted plasma from 0.8 to 1.2 seconds. No probes scanning. Note: Upper divertor pressure rises to 20 mtorr. At 1 second, lower divertor compression ratio is 20 while the upper divertor compression ratio is 45. Shot#13: Testing SSEP controls: SSEP scan from, 18 mm at 0.5 sec to 2 mm at 1.2 sec. No probes scanning. Shot#14: SSEP nice and flat at 15 mm. No probes scanning. Note: lower divertor compression ratio is also flat. Shot#15: SSEP 15 mm, probes scanning Shot#16: SSEP 5 mm, probes scanning. Neutral pumpout seen on upper and lower divertor during L-H high dndt phase. Shot#17,18:SSEP 1 mm. probes scanning. Neutral pumpout seen on upper divertor. Shot#19,20:Failed attempts at upper diverted, i.e., SSEP< 0. No probes scanning. Shot#21: SSEP > 15 mm, no probes scanning Shot#22: SSEP > 15 mm, probes scanning Setup: change to NL04 ~ 0.8 drifting down to 0.7 Shot#23: SSEP > 15 mm, probes scanning Shot#24: SSEP 4 mm, probes scanning Shot#25: SSEP 0 mm, probes scanning Shot#26: SSEP 5 mm, probes scanning. Probe arcing. Shot#27: SSEP 5 mm, probes scanning. -> An excellent run... Special thanks to the engineering crew, Physop, and RF group.

Physics Operator Summaries

Entered: Jul 7 2004 04:37:00:333PM

Author: To Be Determined

Physics Operator's Summary for Friday, 990226 MP#227 H-mode Ion Fueling Experiments MP#229 Secondary Divertor Experiments SL: LaBombard PO: wolfe EO: Silva, Dekow Plan: ----- Today's run consists of two halves. The first part is concerned with determining the source of the density rise in H-mode. Previous observations, e.g. 971219030, indicate the divertor pressure drops at the LH transition and the density rise seems consistent with the depletion of the divertor volume. The question is whether the particles go into the main chamber as neutrals that ionize near the x-point, or as ions that flow back up into the SOL and cross the LCFS in the upper chamber. Both the FSP and ASP probes will be used to monitor flows in the SOL. Target plasma will be 800kA, with RF at 0.9 - 1.2 sec, to allow a steady state L-mode before the transition. We will start with nl4=1.0e20, but may vary the target density. We hope to get steady-state EDA's. On the 1997 shot this was done at relatively low power, <1.5MW. The second half of the run is intended to scope out the possibility of using the upper x-point (secondary separatrix) to funnel particles to the upper divertor. The idea is partly based on the observations of high main chamber recycling fluxes. Again using an 800kA target plasma, we will vary the distance to the second separatrix at several densities, and monitor pressures at the midplane and upper and lower divertor regions. The straightforward way of doing this would be to move the upper xpoint location, but I will explore the possibility of using Strkpsi and/or strkin to directly control the midplane separation (SSEP). I have setup the reference locations for STRKPSI to be (.0.68,0.60),which is on the ceiling, and STRKIN to be (0.53,0.396), which is near the x-point. The controllers for these are calculated, but gains are at zero. We will monitor these signals during the first half of the run. Engineering setup: ------------------ 2 hours ECDC in D2; shut off one hour before the run Power supply settings should be taken from 990225003 TF under hybrid control Gas setup - fill B-top with 6 psi of D2 Hybrid enabled fill B-side lower with 1 psi of Ar Hybrid disabled fill C-side with 30 psi of D2 Hybrid enabled Results: -------- A good run. We started slightly late (~9:40) because of a TORVAC problem, but we completed all of the first experiment, and most of the second mini-proposal. The machine ran well, with only two fizzles out of 27 shots. Almost all the plasmas were useful, except for one early disruption. A new control technique for SSEP was successfully developed. The use of a flux difference controller to control SSEP using the STRKIN algorithms was quite successful, and may be a good way to run the upper x-point control even when SSEP is not crucial. We used STRKIN with RSIN=.53, ZSIN=.396, i.e. near the upper x-point location, and varied the target value from -.015 to +.005. This gave quite nice constant SSEP values (close to the abs(target)) for all cases where EFIT calculated SSEP. On the high negative values the upper null is outside the vessel, and EFIT doesn't find it. The positive values correspond to upper nulls. The two shots where we tried this had disruptions because I was asking for big changes at the start and end of the time with finite gain on STRKIN. Later on, I made these transitions more gradual, and had no more trouble, but we didn't return to the pure upper null, since it wasn't really part of the run plan. we also weren't really set up for upper null since the CLEARIN wire wasn't switched to refer to the upper x-point, so the gaps changed. If we are going to use the flux difference control, we (Ian) should probably set up a wirename in FLUXIHH called SSEP, since STRKIN is confusing. I think there should be no problem in using this control from the beginning of segment 2 and leaving ZXU off or at low gain. We may want to experiment a little with the exact referece point to use. The ZSIN value I took (0.396) is actually lower than our typical ZXu value, which is more like 0.45. Also, I set up the controller to respect the STRKPSI using RSOUT,ZSOUT on the ceiling at (.68,.60), although I never turned STRKPSI contol on. We got good H-modes, including EDA behavior at higher densities and ELM-free at low densities. The EDA's seemed to degrade with time. John reported that Mo levels were elevated today; boronization may be wearing off. RF ran reasonably well at powers up to 1.6MW or so. There were some faults on shots following disruptions which may have been real arcs. JR attempted to inject Zirconium without obvious success. The shit-shooter is still having problems. The g-side ratiomatic died sometime around shot 20, after being noisy much of the day. This will need to be repaired on Monday. Details: -------- Shots #1-6: Ion fueling experiment. NL4=1.0e20, 800kA. RF adjustments, probe changes. Looking at STRKPSI and STRKIN predictor results; noted that setup of STRKIN wasn't as intended, and changed on shot 6. Shot #7-8: continuing ion fueling expt, NL4=1.2e20 Shot #9-10: Fizzles, possibly Br drift (anyhow that's what I tweaked before plasmas returned). Shot #11: Final shot at 1.2e20. Complete dedicated ion fueling shots, although relevant data will be collected the rest of the run as we vary SSEP. Shot #12: NL4 back to 1.0. Initial try with STRKIN control. STRKIN target programmed for linear ramp from -.01 to 0, which is approximately the range through which it seems to sweep on the earlier shots. Turned on P gain=1 (phys gain=5/sec) from 0.5 sec to 1.2sec, then back to zero, and turned ZXU gain down from 6 to 0.5 over the same interval. This resulted in a plasma that went upper null from 0.82 : 1.26sec, reaching a nearly constant error of +5000. It just didn't have enough gain, but it was trying. This was actually a rather interesting looking shot. Shot #13: Raised STRKIN gain from 1.0 to 8.0, and put ZXU gain back up to 2.5 just in case. This worked in the sense that the STRKIN error was near zero and the shot looked similar to the ones with ZXU control (which hadn't been doing much). SSEP ramped from about 18mm to 2mm. Shot #14-15: STRKIN target to -.010, gives a constant SSEP (when you can see it) around 13mm. Error is near zero on PHYS_AOUT Shot #16: Target to -.005, got flat SSEP around 4mm. Pressure goes up in upper divertor. Shot #17-18: Target to -.002, get flat SSEP around 1mm, practically double null. Pressure in upper divertor is up, lower divertor pressure down, pump out at L-H is seen on upper divertor. Shot #19: Try upper null by programming STRKIN=+.005; disrupts at transition to STRKIN control. Big voltage demands saturate EF2U and EF1U. Shot #20: Ramp STRKIN target from -.01 to +.005 in .15sec to reduce the jump. It sort of works, but now disrupts at 1.2+ sec when control switches back to ZXU. It could be made to work, but need to move on. Shot #21-22: Move STRKIN out to -.015 at NL4=1.0e20. Change programming so STRKIN gain starts at .4 and continues through end of shot, with a starting target value of -.01 ramping to final value (in this case -.015) in 0.1 sec. Also, decrease ZXU gain to 1.5 at 0.4sec, and leave it there. I could just start with STRKIN gain and turn ZXU off (or down). This works, but upper triang decreases. X-point is way out of vessel. Note that x-point is no longer close to ZSIN, so the SSEP is probably bigger (if EFIT would calculate it). Shot #23-27: Drop NL4 to 0.8e20 and scan the SSEP (i.e. STRKIN) back down in sequence .015,.005, .002, .005 (repeat). STRKIN works ok on all of these; rampdowns are fine under STRKIN control too. #26 disrupts at 1.1 sec, due to some kind of injection (possibly probe-related). Scorecard: ---------- Plasmas 25 Fizzles 2 Duds 0 ------ --- Total 27

Session Leader Comments
Feb 26 1999 09:49:11:733AM	990226001	Brian Labombard	The first half of the run will be H-mode Ion_Fueling Experiments. ASP and FSP firing in silos. Nice first plasma.
Feb 26 1999 10:15:51:780AM	990226002	Brian Labombard	FSP firing at .65, .85, 1.05 EDA at .85 sec. Has a strange H-alpha behavior - has dithers or something on it. Next shot - improve targeting. More RF start to 0.8 sec. We will try to catch hit the high dndt ramp with the F-scanning probe at 0.85 sec
Feb 26 1999 10:34:10:170AM	990226003	Brian Labombard	FSP firing at .65, .85, 1.05 EDA at .84 sec. Still has dithers or something. Next shot - scan at .65, .865, 1.05
Feb 26 1999 10:46:29:590AM	990226004	Brian Labombard	FSP firing at .65, .865, 1.05 - excellent timing. FSP catches low H-alpha part of high dndt phase of H-mode transition. Next shot - Try for deeper insertion. No argon in next shot.
Feb 26 1999 11:06:57:857AM	990226005	Brian Labombard	FSP firing at .65, .865, 1.05 FSP timing a little late. Try another shot. Pumpout on divertor and midplane seen on these plasmas during H-mode.
Feb 26 1999 11:20:26:750AM	990226006	Brian Labombard	FSP firing at .65, .85, 1.05 Very nice. FSP data looks good. ASP data would be ok if we could use the full bias range on the probes. Next shot - NL04=1.2 target.
Feb 26 1999 11:38:47:780AM	990226007	Brian Labombard	FSP firing at .65, .85, 1.05 Higher density. Did not get 1.2. Timing of FSP is too early for high dndt. Try another shot for higher density and better FSP timing.
Feb 26 1999 11:54:47:327AM	990226008	Brian Labombard	FSP firing at .65, .885, 1.05 Timing OK. Probe arcs at 1.05 sec. Maybe causes transition to ELM-free phase.
Feb 26 1999 12:35:47:810PM	990226011	Brian Labombard	FSP firing at .65, .885, 1.05 Timing of middle scan with density rise is very good. Raw data looks ok. Next shot - back to 1.0 NL04. Steve is going to try and get control of SSEP.
Feb 26 1999 12:51:03:140PM	990226012	Brian Labombard	This shot marks the start of the second miniproposal "Secondary divertor experiments". No probes scanning. This shot became upper diverted around 0.8 sec. Upper divertor pressure rises to 20 mtorr. At 1 sec, lower divertor compression ratio is 20 while the upper divertor compression ratio is 45.
Feb 26 1999 01:14:43:090PM	990226013	Brian Labombard	Very nice demonstration of SSEP control. SSEP ramps from 18 mm at 0.5 sec to 2 mm at 1.2 sec. No probes scanning.
Feb 26 1999 01:30:38:030PM	990226014	Brian Labombard	No probes scanning. SSEP held fixed at around 15 mm. RF tripped out. Next shot - repeat with probes scanning.
Feb 26 1999 01:50:24:577PM	990226015	Brian Labombard	FSP and ASP probes scanning. SSEP held fixed at around 15 mm. Good FSP data. Next shot - repeat with SSEP decreased by 5 mm.
Feb 26 1999 02:04:21:140PM	990226016	Brian Labombard	FSP and ASP probes scanning. SSEP held fixed at around 5 mm. Good FSP data. See neutral pumpout in upper and lower divertors. Next shot - repeat with SSEP decreased to 1? mm.
Feb 26 1999 02:31:23:937PM	990226017	Brian Labombard	FSP and ASP probes scanning. SSEP held fixed at around 0-1 mm. Target moved away. See neutral pumpout in upper divertor. Repeat next shot with deeper insertion.
Feb 26 1999 02:32:14:793PM	990226018	Brian Labombard	FSP and ASP probes scanning. SSEP held fixed at around 0-1 mm. Good probe data. Next shot go for upper diverted. Not probe scan on next shot.
Feb 26 1999 03:21:47:623PM	990226020	Brian Labombard	No probes scanning. Upper diverted. Disrupted.
Feb 26 1999 03:24:08:543PM	990226021	Brian Labombard	No probes scanning. Target looks good. Next shot - repeat and scan probes. Hopefully with better RF.
Feb 26 1999 03:45:21:327PM	990226022	Brian Labombard	FSP and ASP probes scanning. Target is good. RF still tripping. Next shot - lower density, same SSEP.
Feb 26 1999 03:57:30:170PM	990226023	Brian Labombard	FSP and ASP probes scanning. Target is good. SSEP > 12 mm. NL04 target~ 0.8 Next shot go to SSEP ~ 5 mm.
Feb 26 1999 04:20:25:170PM	990226024	Brian Labombard	FSP and ASP probes scanning. Target is good. SSEP ~ 4 mm. NL04 target~ 0.75 Next shot go to SSEP ~ 1 mm.
Feb 26 1999 05:25:41:077PM	990226025	Brian Labombard	FSP and ASP probes scanning. Target is good. SSEP ~ 0 mm. NL04 target~ 0.7 Next shot go back to SSEP ~ 5 mm.
Feb 26 1999 04:55:23:717PM	990226026	Brian Labombard	FSP and ASP probes scanning. Target is good. SSEP ~ 5 mm. NL04 target~ 0.7. Disrupts, in part because the probe arced at 1.05 sec. Next shot - repeat without toasting probe.
Feb 26 1999 05:06:40:700PM	990226027	Brian Labombard	FSP and ASP probes scanning. Target is good. SSEP ~ 5 mm. NL04 target~ 0.7. Good run.

Physics Operator Comments
Feb 25 1999 05:48:13:590PM		Steve Wolfe	Setting up for tomorrow's run. Load from 990225003, an 800kA 1e20 shot with good FSP and ASP targets. Change strkpsi location to (.0.68,0.60) on the ceiling [observer and controller] Change strkin location to (0.53,0.396) (near the x-point) [observer and controller] Save as 990226000 in cmod$root:[hybrid.pcs] Also, LOAD/CLEAN. Should be ready to run. Off, into the snow...
Feb 26 1999 07:17:15:000AM		Steve Wolfe	Continue prepping for the secondary separatrix run: Change title of segment 2 to "0.8 MA Secondary Sep." Shorten Ar pulse to .02 sec. Recalc controllers for STRKIN, SRKPSI, using RSIN,ZSIN,RSOUT,ZSOUT values; leave gains off. Build and Load/Clean Coldstart 26-FEB-1999 07:17:24.82 - ok.
Feb 26 1999 07:33:39:107AM		Steve Wolfe	More tweaking at initial shot - remove TF waggle.
Feb 26 1999 08:24:26:467AM		Steve Wolfe	Today's run consists of two halves. The first part is concerned with determining the source of the density rise in H-mode. Previous observations, e.g. 971219030, indicate the divertor pressure drops at the LH transition and the density rise seems consistent with the depletion of the divertor volume. The question is whether the particles go into the main chamber as neutrals that ionize near the x-point, or as ions that flow back up into the SOL and cross the LCFS in the upper chamber. Both the FSP and ASP probes will be used to monitor flows in the SOL. Target plasma will be 800kA, with RF at 0.9 - 1.2 sec, to allow a steady state L-mode before the transition. We will start with nl4=1.0e20, but may vary the target density. We hope to get steady-state EDA's. On the 1997 shot this was done at relatively low power, <1.5MW. The second half of the run is intended to scope out the possibility of using the upper x-point (secondary separatrix) to funnel particles to the upper divertor. The idea is partly based on the observations of high main chamber recycling fluxes. Again using an 800kA target plasma, we will vary the distance to the second separatrix at several densities, and monitor pressures at the midplane and upper and lower divertor regions. The straightforward way of doing this would be to move the upper xpoint location, but I will explore the possibility of using Strkpsi and/or strkin to directly control the midplane separation (SSEP). I have setup the reference locations for STRKPSI to be (.0.68,0.60),which is on the ceiling, and STRKIN to be (0.53,0.396), which is near the x-point. The controllers for these are calculated, but gains are at zero. We will monitor these signals during the first half of the run.
Feb 26 1999 08:25:41:187AM		Steve Wolfe	Engineering setup: ----------------- 2 hours ECDC in D_2 shut off one hour before the run Power supply settings should be taken from 990225003 TF under hybrid control Gas setup - fill B-top with 6 psi of D2 Hybrid enabled fill B-side lower with 1 psi of Ar Hybrid disabled fill C-side with 30 psi of D2 Hybrid enabled
Feb 26 1999 09:16:06:763AM		Steve Wolfe	There is a delay while a flow switch on the Turbo water lines is fixed/replaced. Estimated time of first plasma = 9:30 - 10:00 AM
Feb 26 1999 09:59:37:670AM	990226001	Steve Wolfe	Shot #1: plasma - good hmode; RF = 900kW Right gap is .01 instead of .015 (why) Visible drop on divertor pressure. Next shot, start RF at 0.82, raise power a little. Spanna crashed after shot 1.
Feb 26 1999 10:09:09:107AM	990226002	Steve Wolfe	Shot #2: repeat shot, with RF on at .82, power increased by 20%. plasma - RF = 1MW (asked for 1.2, D feedback is not giving what it is asked for) good h-mode. Interesting EDA with ELMs? after 1 sec. Next shot turn on Ar. 20msec pulse.
Feb 26 1999 10:25:07:357AM	990226003	Steve Wolfe	Shot #3: Drop end of ZXL ramp by another .005 to compensate for FSP target drift. plasma with h-mode. Similar to shot 2, maybe a little less EDA'ish.
Feb 26 1999 10:43:19:530AM	990226004	Steve Wolfe	Shot #4: Change strkspi and strkin program waveform to .015 Move zxl endpoint ramp down to -0.018 plasma , h-mode. Phys_aout Strkin error is around -10000, strkpsi~-20000 to -11000. Previous, Strkin was around 0 to -4000, and strkpsi was -13000 to 0
Feb 26 1999 10:58:27:750AM	990226005	Steve Wolfe	Shot #5: No Argon this shot. Otherwise the same. Note - the STRKIN position on the previous shots was actually at ZSIN=.6, not ZSIN=.396 as indicated. Not changed for shot 5, will change for shot 6. plasma good hmode, decaying EDA
Feb 26 1999 11:17:57:983AM	990226006	Steve Wolfe	Shot #6: change STRKIN reference to what I thought it was. plasma, hmode, injection at 1.14 Ok, strkin and strkpsi now look very similar: min of strkin is -20000, strkpsi is -22000, qualitatively similar to -ssep trace. Note that I still have programming in for .015 target, so it seems to have an offset or error of some kind. SSEP(.6sec) = 1.4sec; STRKIN error(.6sec)=-18535, which would be 2.3cm. Ar back on for next shot. Go to 1.2e20 next shot.
Feb 26 1999 11:25:33:810AM	990226007	Steve Wolfe	Shot #7: nl4 = 1.2e20, Ar back on. plasma, hmode,target only came up to 1.08. Next shot, increase maintenance gas to 35V. Also, set strkin target back to 0.
Feb 26 1999 11:46:10:090AM	990226008	Steve Wolfe	Shot #8: Increase maint. gas to 35V to try to get nl4=1.2e20 Set strkin target back to 0. plasma, hmode, nl4=1.16e20. turns ELM-free at 1.05sec, maybe Brian's probe? No rad event then. strkin minimum is now -7800 at .47sec.
Feb 26 1999 05:34:46:467PM	990226009	Steve Wolfe	Shot #9: same as last time, but program a ramp on strkin from -.01 to 0 from .5 sec to 1.3sec Rejean ponts out there is a rad event on the edge array; small jump on the 2pi. fizzle. bd at 6msec instead of 5.3msec. Nothing obviously wrong.
Feb 26 1999 12:14:12:653PM	990226010	Steve Wolfe	Shot #10: Reduce pre-puff from 18 to 17 msec. If that doesn't work, I'll lower Br0. still program a ramp on strkin from -.01 to 0 from .5 sec to 1.3sec Another fizzle.
Feb 26 1999 12:28:11:013PM	990226011	Steve Wolfe	Shot #11: Br0 from .002 to .0015 still program a ramp on strkin from -.01 to 0 from .5 sec to 1.3sec plasma , good hmode. long hesitation, almost didn't make it. Current rise is very fast. Next shot, go back to 18msec pre-puff. STRKIN error is around -1000 from .5 to 1.3. Could start control from here.
Feb 26 1999 12:44:33:950PM	990226012	Steve Wolfe	Shot #12: Back down to 1.0e20, V_PG3=25. Turn on STRKIN gain =1 (=5/sec) from 0.5 to 1.2 sec Turn ZXU gain down from 6 to 0.5 from 0.5sec to 1.2sec, then back up to 6. Pre-puff back up to 18msec. Note that ZXU had a -14650 error on previous shot. Warn Brian not to poke. Plasma. No H-mode, RF is ok. early injection(.269) Upper x-point from 0.82 to 1.26sec - Interesting, but NOT what I was after. STRKIN error is +5000, ZXU error is -50,000 Needs more gain.
Feb 26 1999 01:09:32:793PM	990226013	Steve Wolfe	Shot #13: STRKIN gain up from 1.0 to 8.0 ZXU gain up to 2.5 (from 0.5) in the STRKIN interval Plasma, 2hmodes, D-port tripped twice. STRKIN error is zero from .6 to 1.2sec Looks like it is doing what we asked for. Next shot, hold STRKIN flat at -.01.
Feb 26 1999 01:29:25:060PM	990226014	Steve Wolfe	Shot #14: Program STRKIN to -.01 from 0.5: 1.2sec; gains same as on 13 plasma, hmodes, D-port still faulting. SSEP isn't calculating in the region of interest. ZXU must be outside the vessel. STRKIN error is up to nearly 2000 by 1.2 Brian thinks it looks ok, he'll probe it next time. Hopefully RF will stay on too.
Feb 26 1999 01:38:47:733PM	990226015	Steve Wolfe	Shot #15: Repeat. Brian to probe. plasma, RF stayed on, Nice H-mode. Next shot, change strkin to -.005 (from -.010)
Feb 26 1999 01:57:09:030PM	990226016	Steve Wolfe	Shot #16: STRKIN target to -.005 plasma, hmode, SSEP=4.6cm Brian is seeing more pressure in the upper divertor. Lower divertor pressure is around 20mTorr, midplane between 0.2(H) and 0.3 (L-mode)
Feb 26 1999 02:13:49:090PM	990226017	Steve Wolfe	Shot #17: STRKIN (SSEP) target to -.002 from -.005 Shit shooter to inject zirconium at 1.1sec plasma, hmodes, couple of RF faults, H-L at 1.06sec SSEP about 0.1 cm, Damn near double null! This control seems to work well, SSEP is essentially flat. Lower divertor pressure is down to 11mTorr. Upper is close to that in L-mode, then pumps out some.
Feb 26 1999 02:27:27:717PM	990226018	Steve Wolfe	Shot #18: Repeat. plasma, 2 hmodes, RF stays on. Next shot, upper null - ask for +0.005
Feb 26 1999 02:48:59:653PM	990226019	Steve Wolfe	Shot #19: STRKIN target = +.005, i.e. Upper null. Also, drop maint. gas level from 25 to 15V, to avoid increase in target density Disrupted at 0.5sec, just when the STRKIN control took over. Maybe too big a jump? It went up (of course). Yes, both EF1U and EF2U have big jumps (saturating). Previous shot also had large jumps.
Feb 26 1999 03:07:41:107PM	990226020	Steve Wolfe	Shot #20: This time, start STRKIN at -.01, ramp to +.005 between .5sec and .65sec plasma Disrupted at 1.23 sec, presumably the same problem in reverse. Should have done that too. Brian doesn't like the target either.
Feb 26 1999 03:23:01:857PM	990226021	Steve Wolfe	Shot #21: Go the other way: STRKIN to -0.015 between .4 and .5, ZXU down to gain of 1.5 at 0.4. Leave this way through end of shot. Now if I just don't get killed in crossover... Gside ratiomatic is now dead. H-modes, lots of RF faults. STRKIN error is around 2000 for most of this shot. ZXU error is positive 10000:20000 Upper Triangularity is down to 0.25, and the plasma is high.
Feb 26 1999 03:40:04:890PM	990226022	Steve Wolfe	Shot #22: Repeat. plasma , multiple H-modes, RF still faulting. mag traq failures on all three . Recovered them using the RECOVER_TRAQ routines. Run EFIT by hand. Next shot, nl4=0.8
Feb 26 1999 03:52:45:233PM	990226023	Steve Wolfe	Shot #23: Same SSEP, drop density to 0.8e20, reduce maintenance level to 0. RF will try to get more from E-port, D-port seems to be arcing. JR reports that the last shot had the highest Mo level of the week. Plasma, H-modes. RF better. nl4=0.8e20, as requested. outer gap is shrinking.
Feb 26 1999 04:15:05:153PM	990226024	Steve Wolfe	Shot #24: change STRKIN target to -.005 plasma, 2 ELM-free h-modes. Some rf faults. RF people are trying to increase the power after 1.1sec, but it isn't working SSEP ~0.5cm nl4=.7e20 at rf time.
Feb 26 1999 04:32:54:857PM	990226025	Steve Wolfe	Shot #25: Go to the -.002 STRKIN target. Ask Wookie not to try high power on this one; protect the flat plate a little. plasma, h-mode, rf is on at 1.6MW, constant. looks like it went upper null, type III elms? SSEP is nearly 0 (DN). Back to .005
Feb 26 1999 04:47:25:653PM	990226026	Steve Wolfe	Shot #26: STRKIN at -.005 again, Brian wants to improve that data. disruption at 1.1sec. Went down. could be an injection at 1.01sec, kills the h-mode, gets very resistive.
Feb 26 1999 05:01:18:607PM	990226027	Steve Wolfe	Shot #27: Try one more time to get this point. plasma, 3 h-modes, rf faults SSEP=.003 - .004
Feb 26 1999 05:13:11:123PM	990226027	Steve Wolfe	Following the last shot, when the engineers went into the power room they heard the diborane alarm sounding. The Paragon screens showed no alarm and no indication of diborane. We returned to secure access, and Sam and Andy entered the cell wearing SCBA gear. They found the alarm sounding, but no indicaiton of diborane on the PPM display. The alarm reset ok and did not resume sounding. There was no discoloration on the tape. Everything was reset, and access was restored.

Engineering Operator Comments
Shot	Time	Type	Status	Comment
1	09:38:40:060AM	Plasma	Ok	no faults/plasma
2	10:02:14:357AM	Plasma	Ok	no faults/pasma
3	10:18:45:310AM	Plasma	Ok	no faults/plasma
4	10:35:46:937AM	Plasma	Ok	no faults/plasma
5	10:51:45:717AM	Plasma	Ok	no faults/plasma
6	11:05:18:827AM	Plasma	Ok	no faults/plasma
7	11:20:12:187AM	Plasma	Ok	no faults/plasma
8	11:37:55:967AM	Plasma	Ok	no faults/plasma
9	11:54:02:670AM	Plasma	Ok	no faults/plasma
10	12:08:52:590PM	Plasma	Ok	no faults/fizzels
11	12:21:37:920PM	Plasma	Ok	No Faults / Plasma
12	12:36:21:717PM	Plasma	Ok	No Faults / Plasma
13	01:02:39:840PM	Plasma	Ok	No Faults / Plasma
14	01:16:44:107PM	Plasma	Ok	No Faults / Plasma
15	01:31:44:030PM	Plasma	Ok	No Faults / Plasma
16	01:48:50:310PM	Plasma	Ok	No Faults / Plasma
17	02:03:43:340PM	Plasma	Ok	(null)
18	02:18:45:030PM	Plasma	Ok	No Faults / Plasma
19	02:38:18:840PM	Plasma	Ok	No Faults / Plasma
20	02:56:48:403PM	Plasma	Ok	No Faults / Plasma
21	03:13:51:670PM	Plasma	Ok	No Faults / Plasma
22	03:27:36:543PM	Plasma	Ok	No Faults / Plasma
23	03:44:42:873PM	Plasma	Ok	No Faults / Plasma
24	04:08:23:403PM	Plasma	Ok	No Faults / Plasma
25	04:25:35:793PM	Plasma	Ok	No faults / Plasma
26	04:39:54:403PM	Plasma	Ok	No Faults / Plasma
27	04:54:29:590PM	Plasma	Ok	No Faults / Plasma