| Miniproposals | ||||||||||
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| Operators | |
| Session leader(s): | Earl Marmar |
| Physics operator(s): | Joseph Snipes |
| Engineering operator(s): | Andy Pfeiffer,Bill Byford |
| Engineering Operator Run Comment |
| MP496, High Performance Operation at Ip>1.2 MA session leader Earl Marma |
| Session Leader Plans |
| Entered: Apr 8 2008 03:30:14:577PM |
| Author: Earl Marmar |
| Session leader run plan for Wednesday, April 9, 2008
MP496, High Performance Operation at Ip>1.2 MA Piggy-back: MP546, ITER ramp down scenario demonstration (Sips/Wolfe) This run requires boronization over the previous night, and we want to have between shot boronization available as an option during the run. Boronization recipe: 20% diborane/80% helium TC6 foreline pressure: 50 mTorr rmin/rdwell/rmax: 50/75/80 cm tdwell/tsweep: 60 /120s EF4 current: 200 A Pressure change in the bottle: 60 psi Close the diborane bottle prior to the start of the run; personnel should be available to reopen the bottle during the run if/when we decide to start using between-shot boronization. Post boronization ECDC ---------------------------- 1st Gas Setup: Gas: helium sweep: 44/103/45 cm tdwell/tsweep 20/120 s Pressure: 5e-5 Torr Duration: 1 hr 2nd Gas Setup Gas: d2 sweep: 44/103/45cm tdwell/tsweep: 20/120 s Pressure: 2e-4 Torr Duration: 1hr time to stop by 7:00 am __________________________________________ We will start from a 1.35 MA discharge like 1080201002. Target nl_04=1e20 /m^2 ICRF will be required at maximum power available, using all 4 transmitters. J-port is tuned to 78 MHz. D port has a 1 MW source tube. E port is using the FFT. Shot sequence: 1) ICRF boronization recovery - condition to 3 MW total, on at .7 seconds, off at 1.15 seconds (~5 shots) 2) Increase ICRF power, ramping from 3 MW to 5 MW (or max available) linearly between .7 and .8 seconds, then flat until 1.15 seconds (~5 shots) 3) If H-modes are ELM-free and impurity limited, increase nl_04 target density to 1.3e20. Also increase the lower triangularity by decreasing RXL. This should raise q_95 a bit, and combined with higher density, might get us closer to EDA (~5 shots). 4) If all of 1-3 works, increase plasma current in 50 kA steps from shot to shot, ultimately to 1.5 MA (~8 shots) 5) If not, switch to upper single null, with decreased triangularity (target equilibrium TBD). This should decrease edge stability, and along with lower collisionality (density) for upper-null H-modes, might give ELMs for pedestal regulation. nl_04 target should start at 8e19. Throughout the day, monitor molybdenum and radiated power, and evaluate the need for between-shot boronization as the run progresses. Start with argon off, then add moderate argon puff at the discretion of the session leader. Magnet cooling should be monitored carefully, along with RGA and other indicators of machine vacuum, to avoid vacuum leaks during the run. The piggy-back MP will make use of the rampdown portion of the shots, after 1.15 seconds. Details will be given by Sips/Wolfe. If any of the desired rampdown are aggravating high-current disruption/fizzle problems, we will stop doing those parts of the piggy-back MP. If the piggy-back conditions are compatible with moving the plasma vertically down during the rampdown, while maintaining density at or above 2.5e20 /m^3 somewhere in the confined plasma (0.6 < r/a < 0.9 is probably best), this should be done for tests of the 140 GHz reflectometry system. ZCUR changes of up to 5 cm are desired; this should be coordinated with Arturo Dominguez. |
| Entered: Apr 9 2008 07:14:33:377AM |
| Author: Steve Wolfe |
|
Piggyback plan for ITER rampdowns (MP#546) (prepared by George Sips) Being a piggy back experiment....I would propose to try to complete the Ohmic ramp down studies. The repeats are put in to ease the pressure on needing to change the discharge before every pulse. If ramp down changes hold up the next discharge, just repeat with the same settings. 1. 2MA/s ramp down (as 1080201002), Ohmic, minimal shape changes to keep lower divertor. 2. Repeat a few times to get consistent data (or allow some fine tuning to get the shape evolution as desired). Or not to interfere with main programme 3. 4MA/s ramp down, ohmic, ~2 repeats when stable. 4. 1MA/s ramp down, ohmic, ~2 repeats when stable. 5. Optimum ramp down rate (will be close to 2MA/s) keeping OH central currents constant during initial ramp down phase (Vloop~0). If there is time left, repeat the 2MA/s ramp rate, with 1MW ICRH until Ip=300kA. If this does not disrupt, repeat a few times for data consistency to improve the plasma position for RF. |
| Physics Operators Plans |
| Entered: Apr 8 2008 04:13:42:407PM |
| Author: Joseph Snipes |
| Engineering setup and run plan for Wednesday, April 9, 2008
MP496, High Performance Operation at Ip>1.2 MA Piggy-backI: MP546, ITER ramp down scenario demonstration (Sips/Wolfe) Piggy-backII: ZCUR ramps up to 5 cm after 1.15 s with ne > 2.5 x 10^20 m^-3 for 140 GHz reflectometry tests ----------------- Engineering Setup ----------------- Run begins at 09:00 and ends at 18:00 ***Note the extend run time*** Power systems as on:1080201002 Acoil: +Dtop -Dbot -Jtop +Jbot (standard) Hybrid Enabled Gas setup: Fill B-Top with 6 psi D2 Hybrid enabled (PG4) fill B-side lower with 1 psi Ar Hybrid DISABLED (PG1) leave B-side upper as is Hybrid DISABLED (PG2) fill B-main (C-side) with 40 psi D2 Hybrid enabled (PG3) fill NINJA with 10 psi D2 DISABLED Enable gatevalves and shutters: ECE, VUV, Z-bolo Torvac gatevalve toggle (yes/no): no This run requires overnight boronization, and we want to have between shot boronization available as an option during the run. Boronization recipe: 20% diborane/80% helium TC6 foreline pressure: 50 mTorr rmin/rdwell/rmax: 50/75/80 cm tdwell/tsweep: 60 /120s EF4 current: 200 A Pressure change in the bottle: 60 psi Close the diborane bottle prior to the start of the run; personnel should be available to reopen the bottle during the run if/when we decide to start using between-shot boronization. Post boronization ECDC ---------------------------- 1st Gas Setup: Gas: helium sweep: 44/103/45 cm tdwell/tsweep 20/120 s Pressure: 5e-5 Torr Duration: 1 hr 2nd Gas Setup Gas: d2 sweep: 44/103/45cm tdwell/tsweep: 20/120 s Pressure: 2e-4 Torr Duration: 1hr time to stop by 7:00 am ICRF(yes/no): yes LH(yes/no): no DNB(yes/no): yes if available Cryopump (yes/no): no Vessel temperature: 35/35/35 __________________________________________ We will start from a target nl_04=1e20/m^2, 5.4 T, 1.35 MA discharge like 1080201002 and make changes from there trying to get high performance long-lived H-modes possibly increasing the TF to 5.7 T to increase q95 a bit. We may also change to an upper null, lower triangularity plasma depending on how things go. See the Session Leader run plan for more details. |
| Session Leader Summaries |
| Entered: Apr 11 2008 12:40:33:220PM |
| Author: Earl Marmar |
| While the run was hampered by a lot of post disruption fizzles, including many from 1.35 MA, and there was a computer problem that cost several hours in the afternoon, nevertheless we has some interesting shots.
LSN showed the usual problem of ELM-free H-mode, leading to increased radiation and back transitions. On the other hand, there were several shots where the rate of increase in radiated power was not too terrible, and the density appeared to be reaching steady state (shots 14 and 15 are examples). However, most of these shots showed a sudden upturn in dPrad/dt, which usually led to disruption. Matt reports both iron and moly in those rapid increases, with iron appearing to be the worst culprit. Shots 29 and 30 were USN, and showed a very nice enhanced L-mode phase, with low density, controlled radiation, and relatively high confinement (H98 approaching 1 before the H-mode transition). After going into H-mode, radiated power increased linearly in time, until the back transition to L-mode. Following Martin's suggestion, Shot 30 was an attempt to decrease the upper triangularity, to make the edge less stable to ELMs. There was a modest shape change, but no sign of ELMs in the short-lived H-Mode. It might be worth revisiting this shot, with even less triangularity. Also, Thomson scattering was not working on shots 29 and 30, and it would be good to get those measurements. If we could figure out how to keep the plasma from transitioning to H-mode (for the particle transport), while maintaining a very hot edge temperature, that could also be a very interesting regime. |
| Physics Operator Summaries |
| Entered: Apr 9 2008 06:26:03:030PM |
| Author: Joseph Snipes |
| This run was quite a struggle. We had high current disruptions from shot 1 followed nearly always by one or more fizzles. There were 8 shots with rampdowns though three of those disrupted early in the rampdown. These are somewhat useful toward MP546 ITER ramp down scenario demonstration with 4 of those at about the ITER q95. Ip rampdown rates from 1 MA/s, 2 MA/s, and 4 MA/s were obtained. For the main MP496 High Performance Operation we did get a number of H-modes at Ip = 1.35 MA with ICRF power up to 4 MW and stored energy up to 230 kJ. However, the H-modes were very radiative and short lived. There were a total of 30 shots, though shot 25 is missing due to computer problems, but it was a fizzle anyway. Coincident with those problems on shot 25, the Thomson scattering system failed and will need some work tomorrow to get it operating again. The computer problems cost the run a couple of hours. One of those was added back as we ran until 6:00 pm. Of the 30 shots, there were 20 plasmas, 8 fizzles, and two test shots. |
| Session Leader Comments | |||
| Apr 9 2008 09:51:25:220AM | 1080409003 | Earl Marmar | second try at 1.35 MA
Disrupt at .92 seconds got some ICRF, and a short H-mode before the disruption |
| Apr 9 2008 09:52:02:567AM | 1080409004 | Earl Marmar | Ip reduced to 1 MA to ease into things |
| Apr 9 2008 11:39:06:817AM | 1080409009 | Earl Marmar | 1.2 MA, ohmic
H-mode from 1 to 1.25 seconds, some small ELMs wide1 video shows a lot of "stuff" streaming around near the inner wall midplane, from the left edge of the view, going to the right. Matt reports significant iron in these discharges |
| Apr 9 2008 11:37:49:393AM | 1080409010 | Earl Marmar | 1.2 MA
disrupt at 1.2 seconds 2 MW ICRF, H-mode, 150 kJ peak Wtot |
| Apr 9 2008 12:00:23:113PM | 1080409012 | Earl Marmar | 1.2 MA
2 MW ICRF small ELMs, lots of radiated power during H-mode max Wtot .15 MJ |
| Apr 9 2008 12:15:37:347PM | 1080409013 | Earl Marmar | 4 MW ICRF, some trips
non-steady h-modes peak Wtot 0.20 MJ, H89 ~ 1.4 (transiently) |
| Apr 9 2008 12:29:03:330PM | 1080409014 | Earl Marmar | 1.2 MA, 4 MW steady ICRF until it disrupts at .8 seconds
This one looked promising until the radiated power shot up. max Wtot = 0.20 MJ, H89 ~ 1.5 |
| Apr 9 2008 12:58:54:487PM | 1080409016 | Earl Marmar | Ip = 1.35 MA, 4 MW ICRF
several h-modes peak Wtot = 0.22 MJ, H_89 ~ 1.4 |
| Apr 9 2008 02:07:51:797PM | 1080409017 | Earl Marmar | Ip 1.35 MA, ICRF 4 MW with trips
ratty h-modes |
| Apr 9 2008 02:06:29:080PM | 1080409021 | Earl Marmar | Ip 1.35 MA, ICRF trippy, brief intervals at 5 MW
choppy H-modes |
| Apr 11 2008 12:16:22:627PM | 1080409029 | Earl Marmar | trying for upper single null
very interesting shot essentially upper null, but with the x-point basically touching the roof of the upper divertor (flat tiles). Ip 1.35 MA, q_95 = 3.00, delta_upper = .59, delta_lower = .30 ICRF power 4 MW with some trips. Stayed in L-mode for the first 185 msec of ICRF, then went into H-mode (ELM free) and RF started tripping: mostly 3, then 2 MW during the H-mode, which lasted about 90 msec. In L-mode, had hot edge (edge ECE up to 800 eV), Wtot ~ 200kJ, H89 ~ 1.4, H98 ~ .95. In H-mode, edge ECE up to 1000 eV, Wtot ~ 235kJ, H89 ~ 1.8, H98 ~ 1.1 Density is lower in H-mode that for LSN, but rising throughout the H-mode (reaching nl_04 = 1.5e20 at the H to L back transition. |
| Apr 11 2008 12:26:59:410PM | 1080409030 | Earl Marmar | decrease upper triangularity a little (trying to provoke ELMs)
another interesting USN shot x-point slightly lower than on shot 29 Ip 1.35 MA, q_95 = 2.95, delta_upper = .55, delta_lower = .30 ICRF power 4 MW, clean Stayed in L-mode for the first 150 msec of ICRF, then went into H-mode (ELM free) H-mode lasted about 70 msec. In L-mode, had hot edge (edge ECE up to 900 eV), Wtot ~ 197kJ, H89 ~ 1.35, H98 ~ .90. In H-mode, edge ECE up to 1000 eV, Wtot ~ 235kJ, H89 ~ 1.45, H98 ~ .95 Density again rising throughout the H-mode, reaching nl_04 = 1.4e20 at the H to L back transition. |
| Physics Operator Comments | |||
| Apr 9 2008 09:07:39:770AM | 1080409001 | Joseph Snipes | Shot 1: Loaded shot /home/snipes/trees/1080409000 which has a copy of shot 1080201002 in segments 1 and 2 and a copy of segment 2 of that shot in segment 3 set to start at 1.15 s, but with ZXL and ZXU modified in the rampdown to attempt to keep a SNL plasma well into rampdown for George Sips ITER rampdown studies. The ZXU gain was changed in segment 3 from 6 to 8 and the ramp rate of ZXU was reduced and the ramp rate of ZXL was increased. Disrupted at 0.638 s at full current apparently due to an impurity injection at 0.61 s. |
| Apr 9 2008 09:33:44:143AM | 1080409002 | Joseph Snipes | Shot 2: Try again. Fizzle! |
| Apr 9 2008 09:48:12:923AM | 1080409003 | Joseph Snipes | Shot 3: Reduced prepuff by 4 ms to 19 ms duration. Disrupted at 0.925 s. Got a brief H-mode from 0.84 to 0.91 s. |
| Apr 9 2008 09:56:21:033AM | 1080409004 | Joseph Snipes | Shot 4: Reduced prepuff to 17 ms duration. Reduced Ip to 1 MA in segments 2 and 3. Fizzle! |
| Apr 9 2008 10:15:29:783AM | 1080409005 | Joseph Snipes | Shot 5: Returned prepuff to 19 ms duration. Reduced Br0 to -0.5 mT. Opened HIREX gate valve where there is a small air leak that gets pumped out by the main machine pumps. Try again for a 1 MA fiducial. Still disrupted at 0.52 s after an impurity injection at 0.51 s. |
| Apr 9 2008 10:24:42:940AM | 1080409006 | Joseph Snipes | Shot 6: Try again. Disrupted again at 0.945 s following an impurity injection at 0.93 s. |
| Apr 9 2008 10:37:40:377AM | 1080409007 | Joseph Snipes | Shot 7: Moved RXL in by 5 mm to 0. Turned off the ICRF. Good shot. |
| Apr 9 2008 10:59:47:783AM | 1080409008 | Joseph Snipes | Shot 8: Increased prepuff by 3 ms to 22 ms duration. Increased CLEARIN and RCUR and ramped down ZCUR after 1.15 s to -0.01 m in segment 3 in the rampdown. ICRF back on at 2 MW nominal. Disrupted again at 0.878 s. |
| Apr 9 2008 11:08:24:877AM | 1080409009 | Joseph Snipes | Shot 9: Raised Ip to 1.2 MA in segments 2 and 3. ICRF turned off. Reduced prepuff by 2 ms to 20 ms duration. Good shot. |
| Apr 9 2008 11:21:34:877AM | 1080409010 | Joseph Snipes | Shot 10: Reduced ZXU ramp rate in segment 3 by changing the point at 2 s from 0 to 0.01. Increased prepuff by 2 ms to 22 ms duration. Turned ICRF back on. Disrupted at 1.205 s. |
| Apr 9 2008 11:35:13:893AM | 1080409011 | Joseph Snipes | Shot 11: Corrected RXL to 0 just after segment switch in segment 3. Fizzle! |
| Apr 9 2008 11:51:13:440AM | 1080409012 | Joseph Snipes | Shot 12: Reduced prepuff by 2 ms to 20 ms duration. Reduced ZCUR in segments 2 and 3 by -0.005 m to -0.005 m up to the rampdown. Good shot. |
| Apr 9 2008 12:08:50:660PM | 1080409013 | Joseph Snipes | Shot 13: Repeat with 4 MW of ICRF. Disrupted in rampdown at 1.57 s but otherwise a good shot. |
| Apr 9 2008 12:27:27:470PM | 1080409014 | Joseph Snipes | Shot 14: Repeat with 4 MW of ICRF. Disrupted in rampdown at 1.57 s but otherwise a good shot. Disrupted at 0.8 s. |
| Apr 9 2008 12:34:11:753PM | 1080409015 | Joseph Snipes | Shot 15: Reduced prepuff by 2 ms to 18 ms duration. Raised nl04 to 1.1 x 10^20 m^-2. Disrupted at 0.97 s. |
| Apr 9 2008 12:48:16:707PM | 1080409016 | Joseph Snipes | Shot 16: Raised Ip to 1.35 MA and nl04 to 1.2 x 10^20 m^-2. NINJA D2 puff starting at 0.6 s. Good shot. |
| Apr 9 2008 01:01:36:817PM | 1080409017 | Joseph Snipes | Shot 17: Raised prepuff by 4 ms to 22 ms duration. Added ICRF at 1 MW out to 1.65 s for Sips' rampdown experiment. Disrupted at 1.23 s apparently due to an impurity injection at 1.225 s. |
| Apr 9 2008 01:16:43:243PM | 1080409018 | Joseph Snipes | Shot 18: Reduced prepuff by 4 ms back to 18 ms duration. Raising ICRF power to 5 MW up to 1 s. Fizzle! |
| Apr 9 2008 01:29:27:777PM | 1080409019 | Joseph Snipes | Shot 19: Try again. Fizzle! |
| Apr 9 2008 01:42:04:733PM | 1080409020 | Joseph Snipes | Shot 20: Changed Ip rampdown rate to 4 MA/s to end at 1.49 s. Raised prepuff by 3 ms to 21 ms duration. Fizzle again. |
| Apr 9 2008 02:01:30:767PM | 1080409021 | Joseph Snipes | Shot 21: Decreased prepuff by 2 ms to 19 ms duration. Changed rampdown to match the fast rampdown rate in all shape parameters. Runaway shot. Got the ramp down. There were also some H-mode, but the RF tripped a lot. |
| Apr 9 2008 02:11:16:627PM | 1080409022 | Joseph Snipes | Shot 22: Repeat. Disrupted at 0.82 s. |
| Apr 9 2008 02:28:26:657PM | 1080409023 | Joseph Snipes | Shot 23: Reduced prepuff by 3 ms to 19 ms duration. Disrupted at 0.945 s. |
| Apr 9 2008 02:41:37:593PM | 1080409024 | Joseph Snipes | Shot 24: Increased ZCUR to +0.005 m to go to upper null. Changed CLEARIN keyword args to have zxa=+0.39 and then called that wire to go to upper null. Reduced nl04 to 8.5 x 10^19 m^-2. Changed rampdown rate to 1 MA/s and changed all shape parameters accordingly as well as their gains. Fizzle! |
| Apr 9 2008 02:55:02:547PM | 1080409025 | Joseph Snipes | Shot 25: Try again. Changed CLEARIN keyword args to have zxa=+0.39 in segment 3 as well. Runaway fizzle! |
| Apr 9 2008 04:17:38:640PM | 1080409026 | Joseph Snipes | Shot 26: Raised prepuff by 4 ms to 23 ms duration. No power shot after a long delay due to computer problems. |
| Apr 9 2008 04:36:36:110PM | 1080409027 | Joseph Snipes | Shot 27: Try again with plasma. Runaways early. Disrupted at 0.918 s. Data system still has some problems and there are a lot of data missing. More computer problems causing further delays after this shot. |
| Apr 9 2008 05:44:03:157PM | 1080409028 | Joseph Snipes | Shot 28: Lowered ZXU by 0.02 to 0.01 m in segments 2 and 3. Fizzle! Very high fill pressure than was programmed. |
| Apr 9 2008 06:02:06:483PM | 1080409029 | Joseph Snipes | Shot 29: Reduced the prepuff by 6 ms to 17 ms duration. Good shot. |
| Apr 9 2008 06:05:20:907PM | 1080409030 | Joseph Snipes | Shot 30: Increased RXU from -0.02 to -0.01 m in segments 2 and 3. Extended TF flattop to 2.5 s. Ramped down ZCUR faster in segment 3. Disrupted at 1.46 s still above 1 MA. |
| Engineering Operator Comments | ||||
| Shot | Time | Type | Status | Comment |
| 1 | 08:59:56:067AM | Plasma | Ok | |
| 2 | 09:22:09:190AM | Plasma | Ok | |
| 3 | 09:37:27:127AM | Plasma | Ok | |
| 4 | 09:54:04:970AM | Plasma | Ok | |
| 5 | 10:06:35:660AM | Plasma | Ok | |
| 6 | 10:19:26:393AM | Plasma | Ok | |
| 7 | 10:35:45:067AM | Plasma | Ok | |
| 8 | 10:53:23:067AM | Plasma | Ok | |
| 9 | 11:06:12:770AM | Plasma | Ok | |
| 10 | 11:18:40:707AM | Plasma | Ok | |
| 11 | 11:33:04:643AM | Plasma | Ok | |
| 12 | 11:49:08:330AM | Plasma | Ok | |
| 13 | 12:01:43:330PM | Plasma | Ok | |
| 14 | 12:14:11:783PM | Plasma | Ok | |
| 15 | 12:27:49:847PM | Plasma | Ok | |
| 16 | 12:42:16:800PM | Plasma | Ok | |
| 17 | 12:57:33:800PM | Plasma | Bad | OH2U/L and OH1 Commutation Fault |
| 18 | 01:14:48:800PM | Plasma | Ok | |
| 19 | 01:27:29:120PM | Plasma | Ok | |
| 20 | 01:40:06:453PM | Plasma | Ok | |
| 21 | 01:54:38:937PM | Plasma | Ok | |
| 22 | 02:08:19:140PM | Plasma | Ok | |
| 23 | 02:22:18:187PM | Plasma | Ok | |
| 24 | 02:39:29:750PM | Plasma | Ok | |
| 25 | 02:52:16:500PM | Plasma | Ok | |
| 26 | 04:14:36:593PM | Test | Ok | Data System |
| 27 | 04:24:45:657PM | Plasma | Ok | |
| 28 | 05:34:47:220PM | Plasma | Ok | |
| 29 | 05:47:07:627PM | Plasma | Ok | |
| 30 | 06:02:38:983PM | Plasma | Ok | |
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