Miniproposals

Miniproposal: 136a Date Filed: 1/2/1996 Title: Low Single-Pass Absorption Heating with Boronization First Author: Yuichi Takase Session Leader: Yuichi Takase (shots 1-24)

Engineering Operator Run Comment

granetz

Session Leader Plans

Physics Operators Plans

Session Leader Summaries

Entered: Jul 7 2004 03:49:14:993PM

Author: To Be Determined

Run Summary 960124 MP136A Low Single-pass Absorption Heating with Boronization (3.4-7.5T) SL: Takase PO: Granetz EO: Silva/Daigle Part 1. Second harmonic He3 minority heating (3.4-4T, BT rampdown) Part 2. H-He3 mode conversion heating (6.5-7.5T, BT rampup) This was the first run after the second boronization on 960122. Part 1. was completed. This heating scheme had disastrous results before boronization. The reason for unsuccessful heating is thought to be the presence of H fundamental resonance in the high field side edge region. Today's results were more positive. As a result of exploration with different He3 gas puffing and TF ramps (shots 5-9), we found heating and H-mode. With boronization, fundamental H resonance near the edge does not appear to cause problems. Rather, it appears to result in edge heating and helps attain H-mode. Heating got progressively better at higher fields (4->4.8T), presumably because H resonance moves towards the center. It was thought that removing the edge H fundamental resonance by reducing the field (BT<3.4T) may result in better heating, but 2nd harmonic H resonance comes in on the low field side and caused problems (increased impurity and reduced heating). Density and He3 concentration were varied on shots 10-14 at a stationary BT of 4.2T. Lower density and lower He3 concentration seemed to work better, somewhat contrary to expectations. Heating, however, was never as good as H minority heating. This scenario will probably work much better in combination with 40MHz (fundamental He3 minority heating), which can greatly enhance 2nd harmonic He3 absorption at 80MHz. Toward the end of Part 1, it was noticed that the outer gap was nearly zero during RF. Bruce Lipschultz reported large amounts of boron. Part 2. was not completed, largely because of unsuccessful RF coupling. It was impossible to tune with BT ramp (7->7.5T, shots 15-17) because loading changed too much. We had difficulty tuning even with steady BT (shots 18-22). This is not unusual for H-He3 mode conversion heating. This is probably because of reflection from the left-hand cutoff layer in the plasma core, slightly on the low field side of the mode conversion layer. Very little heating was observed on the few shots that we did manage to get some RF, but it is known that careful adjustment of He3 concentration is required to get good central heating. It is also believed that there was a large contamination by deuterium (the proposal asked for two run days to prevent this problem). Shot 001 OH test 002 pl fiducial with Ar, got RF H-mode, Mo 2.e15 with 0.7MW RF, HX warning Part 1. ------- 003 pl breakdown @ 4.9T, rampdown starts @ 0.35s, 3.4T @ 1.15s, RF mistuned He3 puff 90V(.5-.55s)+40V(.55-1.2s), nel_04=0.87->1.13 (n_He3/n_e=12%) 004 pl adjust TF ramp: rampdown starts @ 0.28s, 4.0T @ 0.72s, 3.3T @ 1.1s no RF (mistuned) 005 pl rampdown starts @ 0.28s, 4.0T @ 0.72s, 3.3T @ 1.1s E-port 1.3MW (no heating, no Moly or core radiation increase) power to divertor increases CX increases when H 2nd harm. crosses the edge 006 pl He3 puff reduced to 90V(0.5-0.52s)+40V(0.52-1.2s) 2.3MW, got heating @ 4T (htg reduces at later time) 007 pl He3 puff reduced to 90V(0.5-0.52s)+30V(0.52-1.2s) 2.3MW, htg goes away @ 1.06s (Mo, H_alpha, CX D flux increase) BT=3.3T H2nd harm. @ R=0.83m 008 pl BT 4.4->3.4T (0.7->1.2s) H fund @ R=0.55m @ 4.4T got H-mode at higher field 009 pl BT 4.75->3.8T (0.7->1.2s) H fund @ R=0.60m @ 4.75T got 2 H-modes (4.75T and 4.4T) 010 pl BT=4.2T H fund @ R=0.53m, He3 2nd harm @ R=0.70m, got 2 H-modes again Right gap has been small (fix it on the next shot) 011 pl Right gap fixed (1.5cm now, was almost 0), lost D-port at H-mode 012 pl lower dens. (nel prog = 0.8, was 1.0) lots of H-modes (RF tripping) 013 pl repeat, lots of H-modes (D-port tripping) 014 pl nel prog = 0.6-0.8 @ 0.55s, He3 puff 90V(0.5-0.55s)+40V(0.55-1.2s) RF OK 2.1MW, no H-mode Part 2. ------- 015 pl nel prog = 0.6-1.0 @ 0.4s, He3 puff 90V(0.4-0.45s)+40V(0.45-1.2s) D-port tripped, not much heating TF 6.5-7.5T (0.33-1.1s), should be off-axis MC during RF pulse Reduce He3 and start RF earlier for next shot 016 pl He3 puff 90V(0.4-0.42s)+30V(0.42-1.2s) Both RF tripped (E-port overload) 017 pl nel prog = 0.8-1.0 @ 0.4s Both RF tripped (loading varies over too wide a range) steady BT @ 7.0T for next shot 018 pl BT=7.0T, E-port 1.2MW, no heating 019 pl BT=7.5T, no RF (mistuned) 020 pl BT=7.5T, D-port 1MW, no heating 021 pl BT=7.5T, D-port 1MW, no heating, off-axis ion heating? 022 pl BT=7.2T, no RF ------- 023 pl fiducial, early disruption 024 pl fiducial with Ar, Mo 0.5e15 with 0.75MW RF, RF H-mode @ 1.7MW

Physics Operator Summaries

Entered: Jul 7 2004 04:36:55:863PM

Author: To Be Determined

Physics operator's summary for run 960124: MP 136A -- ICRF Heating w/Low single-pass absorption schemes after boronization SL: Y. Takase PO: R. Granetz EO: F. Silva/J. Daigle Today's run consists of two main parts: (1) 2nd harmonic He3 minority heating in deuterium at 3.4-4.0 tesla, and (2) H-He3 mode conversion heating at 6.5-7.5 tesla. This is the first run after the boronization on 22 Jan, and the hope is that this will noticeably reduce the molybdenum influx, which has been a significant problem with previous attempts to utilize ICRF heating schemes which have low single-pass absorption. Summary: The tokamak ran extremely well today, with no fizzles, no power supply problems, and only one disruption during flattop (a fiducial). Plasmas were run at toroidal fields of 3.2, 3.4, 4.0, 4.5, 7.0, 7.2, and 7.5 tesla, with both static and ramped programming. Plasma currents of 0.6, 0.8, and 1.0 MA were also run. We also ran both deuterium and hydrogen plasmas during the day. Molybdenum levels were low throughout the day. The ICRF worked well at fields below 5 tesla, where He3 minority was used in D2 plasmas. At RF powers of 2.2 MW, some small amount of heating was observed (Wplasma increased 10-15 kJ). There was also significant edge heating. At higher fields, with He3 minority in hydrogen plasmas, the RF had lots of difficulty coupling any appreciable power into the plasma. Scorecard: 23 plasmas 0 fizzles 0 duds 1 tests (standard OH test at beginning of week) ---------- 24 total Run plan: I) Start with the engineering setup from shot 960116037, for an initial fiducial shot. II) After a successful fiducial, we will switch to the engineering setup for 960118035 (a 2.6 tesla shot) for the first half of the run. (1) Hybrid control of the TF must be enabled for this part of the run. (2) Set TF inversion at 1.2 s for this part of the run. (3) Enable hybrid control of B-side-upper (He3) for this part of the run (4) TF will be ramped from 4.8 T @ t=0.3 s to 3.2 at t=1.1 s (5) Set density at nl_04=1.0e20 m-2 (6) Set plasma current at 0.60 MA to begin with. III) For the last part of the run, we will switch to the engineering setup for 960119022 (a 6.5 tesla shot). (1) Switch from D2 to H2 in both the A-side and B-top plena. Same pressures as with deuterium. (2) Keep hybrid control of the TF enabled? (3) TF will be ramped from 6.5 to 7.5 T during the RF pulse. (4) Set plasma current at 1.0 MA. Engineering setup for Wednesday 24 Jan 1996: Discharge clean in helium Fill A-side (actually K-side) plenum with 19-20 psi of deuterium Fill B-top plenum with 5 psi of deuterium. Fill B-side-lower plenum with 4 psi of argon. Confirm that B-side-upper plenum is already filled with 19-20 psi of Helium-3. (If this plenum already contains Helium-3, don't purge it. This stuff is expensive, after all.). DISCONNECT THE PLC CONTROL OF THE VALVE!!! Enable hybrid control of A-side, B-top, and B-side-lower valves for start of run. Enable the ECE, VUV, Moly monitor, PCX, and TCX valves, assuming status of each is okay. Detailed shot log: Shot 01 -- Standard OH1 and OH2 test (first shot of the week). Next shot: setup for fiducial plasma Shot 02 -- Fiducial. Good shot, except for some hard x-rays. The soft x-rays are at their typical (non-boronized) level (5 uA during ohmic). There was argon puffing on this fiducial. The McPherson did not have its voltage turned on. Next shot: start program at 3.4-4.0 tesla. Load in prepared shot which is based on 960118035. Enable hybrid control of TF. Shot 03 -- Plasma. Good shot. Disrupted at 1.30 s during rampdown. No significant Prf. Btor started at 4.87 T and ramped down to 3.4 tesla at t=1.15 s. He3 puff caused density increase of nl=0.24e20. Next shot: tweak TF programming, and improve RCUR programming after t=1.2 s to try and avoid rampdown disruption. Shot 04 -- Plasma. Good shot. Disrupted at 1.29 s. Btor ramped from 4.8 T, through 4.0 T at t=0.72 s, to 3.3 T at 1.1 s. Plasma position jogged outward at 1.2 s and hit the outboard limiter. This turned out to be caused by the switch in RCUR offset at 1.20 s, with the compensating jog in programming not occurring until 1.25 s. Next shot: a small tweak at end of TF ramp, and change time of RCUR offset switch to occur at 1.25 s. Shot 05 -- Plasma. Good shot. Disrupted at 1.29 s again. Density won't pump out at all after 1.2 s, which may be the cause of these rampdown disruptions. Prf=1.25 MW from 0.7 to 1.2 s. No sign of molybdenum, even on the soft x-rays. No sign of any increase in Te or ne either. In fact, there's a small decrease in density and x-rays. Btor passes through 4.0 T at 0.70 s and reaches 3.2 T at 1.10 s. CX and edge probes show a lot of edge heating. Next shot: reduce He3 initial pulse duration from 50 to 20 ms. Also increase argon puff duration from 20 to 30 ms. Shot 06 -- Plasma. Good shot. Still disrupted at 1.30 s. Prf=2.4 MW, then stepping down to 1.4 MW. Still no sign of molybdenum. At the higher RF power, there does appear to be a slight amount of heating...Wplasma increases by 4 kJ. Next shot: slow down Ip rampdown a little bit (to give density a little more time to decay). Also, reduce He3 maintenance level from 40 to 30 volts. Shot 07 -- Plasma. Good shot. Rampdown disruption at 1.32 s. Prf=2.25 MW for the entire time from 0.7 to 1.2 s. Still no molybdenum. Heating seems to drop off as the field ramps to 3.2 T. Next shot: shift TF rampdown later by 0.2 s so that most of the RF pulse will be at around 4 tesla. Shot 08 -- Plasma. Good shot. Rampdown had some minor disruptions to get it it to 200 kA before final disruption. This is an improvement over previous shots today. Prf=2.2 MW, again for nearly 0.5 s. There was an initial increase of 15 kJ in Wplasma, but this was transient. Next shot: shift TF rampdown later by another 0.2 s. Shot 09 -- Plasma. Good shot. Prf=2.2, but there were some dropouts. Several short ELM-free H-modes. Wplasma increases transiently by 15-20 kJ. Btor is now sweeping from 4.75 to 3.80 T during the RF pulse. The outer gap is very close to zero during most of the RF pulse. Next shot: Set Btor at a constant value of 4.2 tesla (114 kA). Shot 10 -- Plasma. Good shot. Btor is constant at 4.23 T from t=0.7 to 1.2 s. Prf=2.2, then 1.5 MW. Multiple brief ELM-free H-modes again. Similar to previous shot. Again the outer gap is getting close to zero. Bruce reports that there is a lot of boron showing up in the plasma during the RF pulse, and I think this may be due to hitting the outer limiter. Next shot: Move RCUR in by 4 mm during the RF pulse. This should increase the outer gap to 8-10 mm. Shot 11 -- Plasma. Good shot. Prf=1.4 MW for most of the pulse. Outer gap is now at 1.5 cm (so is inner gap), but the boron signal is still high from t=0.7 to 1.2 s. It looks like the RF is directly causing erosion of the boron coating. Next shot: reduce density from nl_04=1.0 to 0.8e20 m-2. Shot 12 -- Plasma. Good shot. Prf toggle many times between 2.2 MW and 0, due to many short H-modes. The effects show up on density, Prad, H-alpha, x-rays, Te, etc. Bruce reports that the strike points are sweeping up the divertor face. Next shot: repeat, with RF tuning changes. There was a 16 minute delay while several of us checked on things in the cell and power room. Unfortunately, we breached the access control. Shot 13 -- Plasma. Good shot. RF again toggles off and on in a very repeatible pattern as the plasma toggles into and out of H-mode. Plasma current rampdown was (inexplicably) much smoother. Next shot: reduce density to nl_04=0.6e20 before 0.55 s, and then 0.80e20 after 0.55 s, and increase He3 initial puff duration to 50 ms and increase He3 maintenance voltage to 40 volts. Shot 14 -- Plasma. Good shot. Prf=2.1 MW, constant for 0.5 s. No H-modes. Wplasma increased by 7-10 kJ. Next shot: change to high-field portion of the run. Recall prepared shot based on 960119022. Lots of changes though: raise Ip to 1.0 MA, extend all flattop programming to 1.2 s, density changes, etc. TF is now back under PLC control, with a current limit for 7.5 T (213 kA). Shot 15 -- Plasma. Good 1 MA shot. Rampdown disruption at 1.35 s. Density programming worked well. Prf=1.5, then 2.0 MW. Not much heating. Btor=7.0 T at 0.7 s and 7.5 T at 1.1 s. TF mistakenly inverts at 1.1 s. Next shot: change TF invert time to 1.2 s. Decrease He3 by reducing initial pulse width to 20 ms and reducing maintenance level to 30 V. Shot 16 -- Plasma. Good 1 MA shot. Rampdown disruption at 1.36 s. RF had problems. Next shot: tweak RCUR and CLEARIN after 1.2 s to try and reduce elongation during rampdown. Also tweak density. Shot 17 -- Plasma. Good 1 MA shot. Good rampdown. RF had problems again. NL_04 data lost due to camac problem. These 1 MA shots have had a bad hesitation during the rampup. Next shot: Flattop Btor at 7.0 tesla by reducing the PLC limit to 199 kA. Also, speed up Ip demand to keep up with level achieved at segment switch at 0.1 s, to try and get rid of hesitation. Shot 18 -- Plasma. Good 1 MA shot. Rampup is much better. Good rampdown. Btor flattopped at 7.0 T, as requested. RF worked a little better, but still not acceptable for heating purposes. Next shot: Flattop Btor at 7.5 T from t=0.9 to 1.2 s. This will require starting the TF at -1.2 s instead of -1.0 s, so it may affect the breakdown. Shot 19 -- Plasma. Good 1 MA shot. Btor flattopped at 7.5 T from t=0.8 to 1.2 s, as requested. RF couldn't `get it up'. Next shot: repeat. Shot 20 -- Plasma. Good 1 MA shot. Btor didn't flattop at until t=0.9 s, presumably due to the TF core warming up. RF still couldn't get it up. Next shot: repeat Shot 21 -- Plasma. Good 1 MA shot. Btor flattopped at 0.85 s. RF did a little better, with 0.7 MW injected for 80 ms. Next shot: Reduce Btor to 7.2 tesla (204 kA on PLC limit) Shot 22 -- Plasma. Good 1 MA shot. Btor flattopped at 7.2 T from t=0.6 to 1.2 s, as requested. No RF to speak of. Next shot: switch from hydrogen to deuterium and run a fiducial shot (with argon enabled). Copy from shot 002 earlier today, except increase pre-pulse puff from 10 to 12 ms. Shot 23 -- Fiducial, but disrupted at 0.27 s (upwards). There was a growing vertical oscillation starting back at 0.18 s. Next shot: repeat. Shot 24 -- Fiducial. Good shot. Molybdenum was a lot lower than on this morning's fiducial (about 3 times lower during the ohmic phase). I ran the new fiducial data storage procedure for the ohmic and RF portions of this discharge. End of run.

Session Leader Comments
Jan 24 1996 08:46:37:390AM		Yuichi Takase	MP136A Low Single-pass Absorption Heating with Boronization (3.4-7.5T) SL: Takase PO: Granetz Part 1. Second harmonic He3 minority heating (3.4-4T, BT rampdown) Part 2. H-He3 mode conversion heating (6.5-7.5T, BT rampup)
Jan 24 1996 08:47:41:560AM	960124001	Yuichi Takase	Shot 001: OH test
Jan 24 1996 09:13:55:170AM	960124002	Yuichi Takase	Shot 002: plasma Fiducial (loaded 960116037), with Ar D-port crowbarred HX warning 0.175 Roentgen got RF H-mode Mo 2.e15 with 0.7MW RF
Jan 24 1996 09:45:30:480AM	960124003	Yuichi Takase	Shot 003: plasma breakdown @ 4.9T, rampdown starts @ 0.35s, 3.4T @ 1.15s He3 puff 90V(.5-.55s)+40V(.55-1.2s), nel_04=0.87->1.13 (n_He3/n_e=12%)
Jan 24 1996 09:49:38:930AM	960124004	Yuichi Takase	Shot 004: plasma adjust TF ramp: rampdown starts @ 0.28s, 4.0T @ 0.72s, 3.3T @ 1.1s no RF (mistuned)
Jan 24 1996 10:30:30:780AM	960124005	Yuichi Takase	Shot 005: plasma adjust TF ramp: rampdown starts @ 0.28s, 4.0T @ 0.72s, 3.3T @ 1.1s E-port 1.3MW (no heating, no Moly or core radiation increase) power to divertor increases CX increases when H 2nd harm. crosses the edge
Jan 24 1996 10:40:45:430AM	960124006	Yuichi Takase	Shot 006: plasma He3 puff reduced to 90V(0.5-0.52s)+40V(0.52-1.2s) 2.3MW, got heating @ 4T (htg reduces at later time)
Jan 24 1996 10:53:41:900AM	960124007	Yuichi Takase	Shot 007: plasma He3 puff reduced to 90V(0.5-0.52s)+30V(0.52-1.2s) 2.3MW, htg goes away @ 1.06s (Mo, H_alpha, CX D flux increase) BT=3.3T H2nd harm. @ R=0.83m
Jan 24 1996 11:07:41:430AM	960124008	Yuichi Takase	Shot 008: plasma BT 4.4->3.4T (0.7->1.2s) H fund @ R=0.55m @ 4.4T got H-mode at higher field
Jan 24 1996 11:29:03:810AM	960124009	Yuichi Takase	Shot 009: plasma BT 4.75->3.8T (0.7->1.2s) H fund @ R=0.60m @ 4.75T got 2 H-modes (4.75T and 4.4T)
Jan 24 1996 11:51:50:540AM	960124010	Yuichi Takase	Shot 010: plasma BT=4.2T H fund @ R=0.53m, He3 2nd harm @ R=0.70m, got 2 H-modes again Right gap has been small (fix it on the next shot)
Jan 24 1996 12:05:57:800PM	960124011	Yuichi Takase	Shot 011: plasma Right gap fixed (1.5cm now, was almost 0), lost D-port at H-mode
Jan 24 1996 12:39:39:060PM	960124012	Yuichi Takase	Shot 012: plasma lower dens. (nel prog = 0.8, was 1.0) lots of H-modes (RF tripping)
Jan 24 1996 01:03:31:490PM	960124013	Yuichi Takase	Shot 013: plasma repeat, lots of H-modes (D-port tripping)
Jan 24 1996 01:19:13:580PM	960124014	Yuichi Takase	Shot 014: plasma nel prog = 0.6-0.8 @ 0.55s, He3 puff 90V(0.5-0.55s)+40V(0.55-1.2s) RF OK 2.1MW, no H-mode end of Part 1.
Jan 24 1996 02:29:31:340PM	960124015	Yuichi Takase	Shot 015: plasma start Part 2. loaded 960119022 with modifications. nel prog = 0.6-1.0 @ 0.4s, He3 puff 90V(0.4-0.45s)+40V(0.45-1.2s) D-port tripped, not much heating TF 6.5-7.5T (0.33-1.1s), should be off-axis MC during RF pulse reduce He3 and start RF earlier for next shot.
Jan 24 1996 02:32:51:060PM	960124016	Yuichi Takase	Shot 016: plasma He3 puff 90V(0.4-0.42s)+30V(0.42-1.2s) Both RF tripped (E-port overload)
Jan 24 1996 03:01:43:040PM	960124017	Yuichi Takase	Shot 017: plasma nel prog = 0.8-1.0 @ 0.4s Both RF tripped (loading varies over too wide a range) steady BT @ 7.0T for next shot
Jan 24 1996 04:33:46:770PM	960124018	Yuichi Takase	Shot 018: plasma BT=7.0T, E-port 1.2MW, no heating
Jan 24 1996 04:35:07:450PM	960124019	Yuichi Takase	Shot 019: plasma BT=7.5T, no RF (mistuned)
Jan 24 1996 04:40:02:860PM	960124020	Yuichi Takase	Shot 020: plasma BT=7.5T, D-port 1MW, no heating
Jan 24 1996 04:40:41:900PM	960124021	Yuichi Takase	Shot 021: plasma BT=7.5T, D-port 1MW, no heating, off-axis ion heating?
Jan 24 1996 04:41:39:450PM	960124022	Yuichi Takase	Shot 022: plasma BT=7.2T, no RF
Jan 24 1996 05:03:26:530PM	960124023	Yuichi Takase	Shot 023: plasma (early disruption) fiducial attempt
Jan 24 1996 05:48:52:700PM	960124024	Yuichi Takase	Shot 024: plasma fiducial with Ar, Mo 0.5e15 with 0.75MW RF, RF H-mode @ 1.7MW

Physics Operator Comments
Jan 23 1996 05:33:16:020PM	960124001	Robert Granetz	MP 136A -- ICRF Heating w/Low single-pass absorption schemes after boronization SL: Y. Takase PO: R. Granetz EO: Today's run consists of two main parts: (1) 2nd harmonic He3 minority heating in deuterium at 3.4-4.0 tesla, and (2) H-He3 mode conversion heating at 6.5-7.5 tesla. This is the first run after the boronization on 22 Jan, and the hope is that this will noticeably reduce the molybdenum influx, which has been a significant problem with previous attempts to utilize ICRF heating schemes which have low single-pass absorption.
Jan 23 1996 05:33:56:690PM	960124001	Robert Granetz	Engineering setup for Wednesday 24 Jan 1996: Discharge clean in helium Fill A-side (actually K-side) plenum with 19-20 psi of deuterium Fill B-top plenum with 5 psi of deuterium. Fill B-side-lower plenum with 4 psi of argon. Confirm that B-side-upper plenum is already filled with 19-20 psi of Helium-3. (If this plenum already contains Helium-3, don't purge it. This stuff is expensive, after all.). DISCONNECT THE PLC CONTROL OF THE VALVE!!! Enable hybrid control of A-side, B-top, and B-side-lower valves for start of run. Enable the ECE, VUV, Moly monitor, PCX, and TCX valves, assuming status of each is okay.
Jan 23 1996 05:35:08:620PM	960124001	Robert Granetz	Run plan: I) Start with the engineering setup from shot 960116037, for an initial fiducial shot. II) After a successful fiducial, we will switch to the engineering setup for 960118035 (a 2.6 tesla shot) for the first half of the run. (1) Hybrid control of the TF must be enabled for this part of the run. (2) Set TF inversion at 1.2 s for this part of the run. (3) Enable hybrid control of B-side-upper (He3) for this part of the run (4) TF will be ramped from 4.8 T @ t=0.3 s to 3.2 at t=1.1 s (5) Set density at nl_04=1.0e20 m-2 (6) Set plasma current at 0.60 MA to begin with.
Jan 23 1996 05:35:27:280PM	960124001	Robert Granetz	III) For the last part of the run, we will switch to the engineering setup for 960119022 (a 6.5 tesla shot). (1) Switch from D2 to H2 in both the A-side and B-top plena. Same pressures as with deuterium. (2) Keep hybrid control of the TF enabled? (3) TF will be ramped from 6.5 to 7.5 T during the RF pulse. (4) Set plasma current at 1.0 MA.
Jan 24 1996 08:43:03:680AM	960124001	Robert Granetz	Shot 01 -- OH1 and OH2 test (first shot of the week). Good. Next shot: setup for fiducial plasma
Jan 24 1996 08:59:44:370AM	960124002	Robert Granetz	Shot 02 -- Fiducial. Good shot, except for some hard x-rays. The soft x-rays are at their typical (non-boronized) level (5 uA during ohmic). There was argon puffing on this fiducial. Next shot: start program at 3.4-4.0 tesla. Load in prepared shot which is based on 960118035. Enable hybrid control of TF.
Jan 24 1996 09:26:17:540AM	960124003	Robert Granetz	Shot 03 -- Plasma. Good shot. Disrupted at 1.30 s during rampdown. No significant Prf. Btor started at 4.87 T and ramped down to 3.4 tesla at t=1.15 s. He3 puff caused density increase of nl=0.24e20. Next shot: tweak TF programming, and improve RCUR programming after t=1.2 s to try and avoid rampdown disruption.
Jan 24 1996 09:46:46:970AM	960124004	Robert Granetz	Shot 04 -- Plasma. Good shot. Disrupted at 1.29 s. Btor ramped from 4.8 T, through 4.0 T at t=0.72 s, to 3.3 T at 1.1 s. Plasma position jogged outward at 1.2 s and hit the outboard limiter. This turned out to be caused by the switch in RCUR offset at 1.20 s, with the compensating jog in programming not occurring until 1.25 s. Next shot: a small tweak at end of TF ramp, and change time of RCUR offset switch to occur at 1.25 s.
Jan 24 1996 10:21:14:030AM	960124005	Robert Granetz	Shot 05 -- Plasma. Good shot. Disrupted at 1.29 s again. Density won't pump out at all after 1.2 s, which may be the cause of these rampdown disruptions. Prf=1.25 MW from 0.7 to 1.2 s. No sign of molybdenum, even on the soft x-rays. No sign of any increase in Te or ne either. In fact, there's a small decrease in density and x-rays. Btor passes through 4.0 T at 0.70 s and reaches 3.2 T at 1.10 s. CX and edge probes show a lot of edge heating. Next shot: reduce He3 initial pulse duration from 50 to 20 ms. Also increase argon puff duration from 20 to 30 ms.
Jan 24 1996 10:17:53:350AM	960124006	Robert Granetz	Shot 06 -- Plasma. Good shot. Still disrupted at 1.30 s. Prf=2.4 MW, then stepping down to 1.4 MW. Still no sign of molybdenum. At the higher RF power, there does appear to be a slight amount of heating...Wplasma increases by 4 kJ. Next shot: slow down Ip rampdown a little bit (to give density a little more time to decay). Also, reduce He3 maintenance level from 40 to 30 volts.
Jan 24 1996 10:42:53:610AM	960124007	Robert Granetz	Shot 07 -- Plasma. Good shot. Rampdown disruption at 1.32 s. Prf=2.25 MW for the entire time from 0.7 to 1.2 s. Still no molybdenum. Heating seems to drop off as the field ramps to 3.2 T. Next shot: shift TF rampdown later by 0.2 s so that most of the RF pulse will be at around 4 tesla.
Jan 24 1996 10:59:39:650AM	960124008	Robert Granetz	Shot 08 -- Plasma. Good shot. Rampdown had some minor disruptions to get it it to 200 kA before final disruption. This is an improvement over previous shots today. Prf=2.2 MW, again for nearly 0.5 s. There was an initial increase of 15 kJ in Wplasma, but this was transient. Next shot: shift TF rampdown later by another 0.2 s.
Jan 24 1996 11:29:25:390AM	960124009	Robert Granetz	Shot 09 -- Plasma. Good shot. Prf=2.2, but there were some dropouts. Several short ELM-free H-modes. Wplasma increases transiently by 15-20 kJ. Btor is now sweeping from 4.75 to 3.80 T during the RF pulse. The outer gap is very close to zero during most of the RF pulse. Next shot: Set Btor at a constant value of 4.2 tesla (114 kA).
Jan 24 1996 11:47:19:470AM	960124010	Robert Granetz	Shot 10 -- Plasma. Good shot. Btor is constant at 4.23 T from t=0.7 to 1.2 s. Prf=2.2, then 1.5 MW. Multiple brief ELM-free H-modes again. Similar to previous shot. Again the outer gap is getting close to zero. Bruce reports that there is a lot of boron showing up in the plasma during the RF pulse, and I think this may be due to hitting the outer limiter. Next shot: Move RCUR in by 4 mm during the RF pulse. This should increase the outer gap to 8-10 mm.
Jan 24 1996 12:04:43:380PM	960124011	Robert Granetz	Shot 11 -- Plasma. Good shot. Prf=1.4 MW for most of the pulse. Outer gap is now at 1.5 cm (so is inner gap), but the boron signal is still high from t=0.7 to 1.2 s. It looks like the RF is directly causing erosion of the boron coating. Next shot: reduce density from nl_04=1.0 to 0.8e20 m-2.
Jan 24 1996 12:18:57:270PM	960124012	Robert Granetz	Shot 12 -- Plasma. Good shot. Prf toggle many times between 2.2 MW and 0, due to many short H-modes. The effects show up on density, Prad, H-alpha, x-rays, Te, etc. Bruce reports that the strike points are sweeping up the divertor face. Next shot: repeat, with RF tuning changes.
Jan 24 1996 01:02:34:290PM	960124013	Robert Granetz	Shot 13 -- Plasma. Good shot. RF again toggles off and on in a very repeatible pattern as the plasma toggles into and out of H-mode. Plasma current rampdown was (inexplicably) much smoother. Next shot: reduce density to nl_04=0.6e20 before 0.55 s, and then 0.80e20 after 0.55 s, and increase He3 initial puff duration to 50 ms and increase He3 maintenance voltage to 40 volts.
Jan 24 1996 01:34:06:370PM	960124014	Robert Granetz	Shot 14 -- Plasma. Good shot. Prf=2.1 MW, constant for 0.5 s. No H-modes. Wplasma increased by 7-10 kJ. Next shot: change to high-field portion of the run. Recall prepared shot based on 960119022. Lots of changes though: raise Ip to 1.0 MA, extend all flattop programming to 1.2 s, density changes, etc. TF is now back under PLC control, with a current limit for 7.5 T (213 kA).
Jan 24 1996 01:52:10:420PM	960124015	Robert Granetz	Shot 15 -- Plasma. Good 1 MA shot. Rampdown disruption at 1.35 s. Density programming worked well. Prf=1.5, then 2.0 MW. Not much heating. Btor=7.0 T at 0.7 s and 7.5 T at 1.1 s. TF mistakenly inverts at 1.1 s. Next shot: change TF invert time to 1.2 s. Decrease He3 by reducing initial pulse width to 20 ms and reducing maintenance level to 30 V.
Jan 24 1996 02:12:16:310PM	960124016	Robert Granetz	Shot 16 -- Plasma. Good 1 MA shot. Rampdown disruption at 1.36 s. RF had problems. Next shot: tweak RCUR and CLEARIN after 1.2 s to try and reduce elongation during rampdown. Also tweak density.
Jan 24 1996 02:51:46:210PM	960124017	Robert Granetz	Shot 17 -- Plasma. Good 1 MA shot. Good rampdown. RF had problems again. NL_04 data lost due to camac problem. These 1 MA shots have had a bad hesitation during the rampup. Next shot: Flattop Btor at 7.0 tesla by reducing the PLC limit to 199 kA. Also, speed up Ip demand to keep up with level achieved at segment switch at 0.1 s, to try and get rid of hesitation.
Jan 24 1996 03:11:28:710PM	960124018	Robert Granetz	Shot 18 -- Plasma. Good 1 MA shot. Rampup is much better. Good rampdown. Btor flattopped at 7.0 T, as requested. RF worked a little better, but still not acceptable for heating purposes. Next shot: Flattop Btor at 7.5 T from t=0.9 to 1.2 s. This will require starting the TF at -1.2 s instead of -1.0 s, so it may affect the breakdown.
Jan 24 1996 03:31:04:440PM	960124019	Robert Granetz	Shot 19 -- Plasma. Good 1 MA shot. Btor flattopped at 7.5 T from t=0.8 to 1.2 s, as requested. RF couldn't `get it up'. Next shot: repeat.
Jan 24 1996 04:00:07:490PM	960124020	Robert Granetz	Shot 20 -- Plasma. Good 1 MA shot. Btor didn't flattop at until t=0.9 s, presumably due to the TF core warming up. RF still couldn't get it up. Next shot: repeat
Jan 24 1996 04:16:53:110PM	960124021	Robert Granetz	Shot 21 -- Plasma. Good 1 MA shot. Btor flattopped at 0.85 s. RF did a little better, with 0.7 MW injected for 80 ms. Next shot: Reduce Btor to 7.2 tesla (204 kA on PLC limit)
Jan 24 1996 04:39:59:880PM	960124022	Robert Granetz	Shot 22 -- Plasma. Good 1 MA shot. Btor flattopped at 7.2 T from t=0.6 to 1.2 s, as requested. No RF to speak of. Next shot: switch from hydrogen to deuterium and run a fiducial shot (with argon enabled). Copy from shot 002 earlier today, except increase pre-pulse puff from 10 to 12 ms.
Jan 24 1996 05:07:00:170PM	960124023	Robert Granetz	Shot 23 -- Fiducial, but disrupted at 0.27 s (upwards). There was a growing vertical oscillation starting back at 0.18 s. Next shot: repeat.
Jan 24 1996 05:36:31:480PM	960124024	Robert Granetz	Shot 24 -- Fiducial. Good shot. Molybdenum was a lot lower than on this morning's fiducial (about 3 times lower during the ohmic phase). I ran the new fiducial data storage procedure for the ohmic and RF portions of this discharge. End of run.

Engineering Operator Comments
Shot	Time	Type	Status	Comment
1	05:30:33:210PM	Test	Ok	oh test
2	08:52:09:890AM	Plasma	Ok	fiducial
3	09:09:17:180AM	Plasma	Ok
4	09:29:25:750AM	Plasma	Ok
5	09:47:28:290AM	Plasma	Ok	no faults
6	10:06:52:170AM	Plasma	Ok
7	10:23:00:770AM	Plasma	Ok
8	10:44:55:750AM	Plasma	Ok
9	11:02:32:470AM	Plasma	Ok
10	11:28:34:290AM	Plasma	Ok
11	11:48:13:570AM	Plasma	Ok
12	12:06:44:410PM	Plasma	Ok
13	12:42:23:560PM	Plasma	Ok
14	01:02:25:650PM	Plasma	Ok
15	01:38:08:980PM	Plasma	Ok
16	02:01:06:150PM	Plasma	Ok
17	02:33:54:920PM	Plasma	Ok
18	02:57:51:560PM	Plasma	Ok
19	03:20:40:350PM	Plasma	Ok
20	03:44:00:680PM	Plasma	Ok
21	04:06:40:300PM	Plasma	Ok
22	04:29:31:090PM	Plasma	Ok
23	04:54:58:220PM	Plasma	Ok
24	05:04:36:410PM	Plasma	Ok