| Miniproposals | ||||||||||
|
| Operators | |
| Session leader(s): | Martin Greenwald |
| Physics operator(s): | Bill Rowan |
| Engineering operator(s): | Unknown |
| Engineering Operator Run Comment |
| Purpose: MP #347 C-Mod Performance Evaluation/Greenwald/Rowan |
| Session Leader Plans |
| Physics Operators Plans |
| Session Leader Summaries |
| Entered: Jul 7 2004 03:49:33:413PM |
| Author: Martin Greenwald |
| Run Summary for 1030701 MP 347 Session Leader Greenwald Phys Op Rowan Plan: We will attempt to study performance issues by running inner-wall limited discharges with strong RF heating at 0.8 MA. The total power will be moderately high, but we should not push performance - the power should be steady except for programmed notches designed to allow evaluation of the absorbed power via dW/dt analysis. Separate trips on each of the 3 antennas will be programmed to allow separate evaluation of each. These studies will be carried out at a variety of densities. Recent experiments suggested that lower density - thus hotter - plasmas show better heating. If time permits, plasma currents of 0.6 and 1.0 MA could be run as well. The L-mode studies will take about 0.4 seconds of each discharge. Following this period, the inner gap will be increased from 0 to about 1 cm to allow an H-mode plasma to develop from a fully heated discharge. This would provide further tests for the scaling of heating efficiency with temperature. Careful spectroscopic study of impurities should accompany these experiments to determine the extent to which low or high Z impurities are present. Boron or nitrogen from the BN tiles may be a factor in the apparent drop in plasma performance. We start with 10305300014 - an inner wall limited plasma from earlier this campaign. The RF should be set to run from 0.7 to 1.5 sec. Notches should be programmed in right from the start: D @ 0.8, 1.2 sec E @ 0.9, 1.3 sec J @ 1.0, 1.4 sec We work up to high power in all antennas. We can start modifying the equilibrium in the second half of the shot early in the run - even if we don't have the first part fully set up. The plan is to pull the plasma off the inner wall (L gap to ~ 1cm) and form a lower single null discharge. The change should start at about 1.05 second and be fairly rapid. We want the A coils setup up for minimal error field for the entire run. Results: Fairly good. The start was delayed by attempts to fix power systems for the D antenna. Eventually we gave up on this and ran with only E and J. This limited our ability to run at very high densities as J won't start in these cases. The overall confinement followed results from earlier years quite closely. Data from different currents overlaid (using ITER89 scaling). The degradation in performance as density was raised was also observed. H factors varied from 1.3 at nebar ~ 1e20 to 0.7 at nebar > 2.5e20. We got fast efits for all the RF power notches. The data will take closer inspection as the time histories don't always look right. Unclear if this is a problem with the timebaseor something more fundamental about the approach. The attempt to form good H-modes by pulling the plasma off the inner wall after it was heated did not work at all. The H-modes produced were all terrible. Initial analysis of fast H-alpha data from the edge suggests that there is no rapidchange in the edge plasma associated with RF turn off (or on). Shots for further analysis: 1030701001 1030701002 1030701003 1030701005 1030701006 1030701007 1030701008 1030701009 1030701010 1030701011 1030701012 1030701013 1030701015 1030701018 1030701019 1030701020 1030701021 1030701022 1030701023 1030701024 1030701026 |
| Physics Operator Summaries |
| Entered: Jul 7 2004 04:37:18:503PM |
| Author: Bill Rowan |
| Physop Summary for Tuesday, July 1, 2003. Run 1030701 Purpose: MP#347 C-Mod Performance Evaluation SL: Greenwald PO: Rowan Engineering Setup for Tuesday 07/01/2003--------------------------- Run starts at 09:00 ECDC in D2 at 2e-4 Torr, stopping by 07:00 Power Systems as on 1030501026 A-coils setup: [+Dtop -Dbot -Jtop +Jbot] Gas setup: fill B-Top with 6 psi D2 Hybrid enabled (PG4) fill B-side lower with 1 psi Ar Hybrid enabled (PG1) fill B-side upper with 10 psi D2 Hybrid DISABLED (PG2) (for ECDC) fill C-side with 30 psi D2 Hybrid enabled (PG3) Enable the following gate valves, assuming no vacuum problems: ECE, DNB, VUV All ICRF transmitters will be needed for this run. ------------------------------------------------------------------ Results--------------------------------------------------------------- We started from shot 1030501026. This was a limited on the high field side. The startup was from shot 1030630004. In this setup, the current is notched during the current rise (at times), and there is a hard x-ray burst starting at early time. Both would be worth some attention, but that is difficult to justify at the expense of the main purpose of the run. There was an initial request to increase the elongation of the limited discharge from approximately 1.3 to something closer to 1.5. This was easily accomplished by fine tuning using clearin and rcur; that is, by moving in the direction of a diverted equilibrium. The equilibrium was adjusted at 1.1 s to produce a diverted configuration late in the discharge. There were disruptions on shot 007, 008, and 012. On Wednesday, Wolfe compared these to discharges during his run and concluded that there were problems with the EF2 supply -- pickup, noise... See his log for 1030702. Score card plasma 19 disruptions 3 all after 1s fizzles 4 total 26 ------------------------------------------------------------------- Details---------------------------------------------------------- Loaded shot 1030501026. Will load segment 1 from yesterday. 1030630004 set up the a coils for the first shot. Turned on at 0.5s and off at 1.5 s D is not available. Starting the run without it. 001. Plasma. Startup is okay. Discharge looks like a good place to start. Limited on the high field side H/D ratio incorrect. Next shot. No pcs changes. 002. Plasma. Next shot. Changed clearin from -0.03 m to -0.02 m Increased RCUR by 0.005 at the same time 003. Plasma elongation is approx 1.4 Next shot. Leave the initial elongation alone at 1.05 s begin to pull the plasma off the inner wall clearin increased by 0.01 m. rcur increased by 0.005m 004. Plasma. Does become diverted at approximately 1s The right gap gets a little small. Next shot. Increase clearin by another 0.01 m 005. Plasma. Right gap corrected to approximately 1 cm Next shot. No pcs changes 006. Plasma Next shot. No pcs changes 007. Plasma. Disruption at 1.5s. Next shot. No PCS changes. 008. Plasma. Disruption at 1.5 s again Next shot. Flatten the density and reduce the nl_04 demand to 4.0e+19 009. Plasma. Density still not flat. Next shot. Flatten the density so that is near nebar =1.0e+20 m-3 010. Plasma Density is reasonably flat. Next shot. Reduce the density in the first part of the shot. Increase the pre puff from 26 ms to 30 ms to take care of x-ray 011. Plasma Next shot. Increase nl_04 to 1.5e+20 012. Plasma. Disruption at 1.17s Next shot. Reduce the density by approximately 30% 013. Plasma. Full length. Next shot. No pcs changes. 014. Fizzle Next shot. Reduce the prefill fro 30 ms to 26 ms 015. Plasma. Next shot. Increase IP to 1 MA Slight reduction in density. 016. Fizzle Next shot. Bz0 may be a little high. Reduced it icef4 from -1320A to -1335A 017. fizzle Next shot. Raise ICEF$ from -1335 to -1305 This is going in the other direction wrt my previous change 018. Plasma. Long delay before this shot. There appears to be a vacuum leak. BZ_0 responded as expected. Next shot. Change the equilibrium to remain limited throughout the shot. 019. Plasma. Limited on the inner wall. Next shot. Reduce nl_04 demand from 0.9e+20 to 0.6e+20 020. Plasma Next shot. Reducet the nl_04 demand from 0.6e+20 to 0.45e+20 021. Plasma. Next shot. 0.6 MA 022. Plasma. Next shot. Increased nl_04 demand from 4.5e+19 to 7.0e+19 Increase the prefill from 26 ms to 30 ms 023. Plasma Next shot. Further increase in nl_04 demand from 7.0e+19 to 9e+19 024. Plasma Next shot. Further increased in nl_04 demand from 9e+19 to 1.1e+20 025. Fizzle Next shot. Decrease the prefill from 30 ms to 26 ms 026. Plasma. Last shot. |
| Session Leader Comments | |||
| Jul 1 2003 09:04:02:753AM | Martin Greenwald | MP#347 C-Mod Performance Evaluation SL: Greenwald PO: Rowan Plan: We will attempt to study performance issues by running inner-wall limited discharges with strong RF heating at 0.8 MA. The total power will be moderately high, but we should not push performance - the power should be steady except for programmed notches designed to allow evaluation of the absorbed power via dW/dt analysis. Separate trips on each of the 3 antennas will be programmed to allow separate evaluation of each. These studies will be carried out at a variety of densities. Recent experiments suggested that lower density - thus hotter - plasmas show better heating. If time permits, plasma currents of 0.6 and 1.0 MA could be run as well. The L-mode studies will take about 0.4 seconds of each discharge. Following this period, the inner gap will be increased from 0 to about 1 cm to allow an H-mode plasma to develop from a fully heated discharge. This would provide further tests for the scaling of heating efficiency with temperature. Careful spectroscopic study of impurities should accompany these experiments to determine the extent to which low or high Z impurities are present. Boron or nitrogen from the BN tiles may be a factor in the apparent drop in plasma performance. We start with 10305300014 - an inner wall limited plasma from earlier this campaign. The RF should be set to run from 0.7 to 1.5 sec. Notches should be programmed in right from the start: D @ 0.8, 1.2 sec E @ 0.9, 1.3 sec J @ 1.0, 1.4 sec We work up to high power in all antennas. We can start modifying the equilibrium in the second half of the shot early in the run - even if we don't have the first part fully set up. The plan is to pull the plasma off the inner wall (L gap to ~ 1cm) and form a lower single null discharge. The change should start at about 1.05 second and be fairly rapid. We want the A coils setup up for minimal error field for the entire run. | |
| Jul 1 2003 10:23:49:953AM | Martin Greenwald | We're going to get started without D port antenna We should be starting in another 10-15 minutes | |
| Jul 1 2003 05:53:44:740PM | Martin Greenwald | Results: Fairly good. The start was delayed by attempts to fix power systems for the D antenna. Eventually we gave up on this and ran with only E and J. This limited our ability to run at very high densities as J won't start in these cases. The overall confinement followed results from earlier years quite closely. Data from different currents overlaid (using ITER89 scaling). The degradation in performance as density was raised was also observed. H factors varied from 1.3 at nebar ~ 1e20 to 0.7 at nebar > 2.5e20. We got fast efits for all the RF power notches. The data will take closer inspection as the time histories don't always look right. Unclear if this is a problem with the timebaseor something more fundamental about the approach. The attempt to form good H-modes by pulling the plasma off the inner wall after it was heated did not work at all. The H-modes produced were all terrible. Initial analysis of fast H-alpha data from the edge suggests that there is no rapidchange in the edge plasma associated with RF turn off (or on). Shots for further analysis: 1030701001 1030701002 1030701003 1030701005 1030701006 1030701007 1030701008 1030701009 1030701010 1030701011 1030701012 1030701013 1030701015 1030701018 1030701019 1030701020 1030701021 1030701022 1030701023 1030701024 1030701026 | |
| Jul 1 2003 11:10:40:903AM | 1030701001 | Martin Greenwald | Good shot RF total to 2 MW 1.1 from E, 0.85 from J4 appropriate notches break in slope in fast efits look a bit strange H factors (frac = .9) are slightly above 1 radiation is low something seems wrong with h/d ratio - though raw spectra are present |
| Jul 1 2003 11:35:11:690AM | 1030701002 | Martin Greenwald | Good Shot More RF power, but lots of trips on J Hard to evaluate, but H factors look OK still issues with H/D and EFIT |
| Jul 1 2003 12:37:01:143PM | 1030701006 | Steve Wolfe | Shot #6: Steve says ge is getting closer to correct phase. Lots of faults on J, need it to be cleaner to evaluate notches. |
| Jul 1 2003 12:48:21:223PM | 1030701007 | Steve Wolfe | Shot #7: Lots of hard xrays, disrupted at 1.5sec 2.6MW total, Steve says phase is good. L-mode notches look good, both the ones in H-mode are just following an ELMy burst (or whatever), so the b-i-s is tent-shaped rather than a straight fall. |
| Jul 1 2003 01:00:42:150PM | 1030701008 | Steve Wolfe | Shot #8: Another disruptionm, RF ran clean but density is dropping at the end. If this is an H-mode it's really strange. Density falls, stored energy is nearly constant, and the Halpha bursts are confusing the notches. Next shot: Move on to the lower density case and flatten it out. |
| Jul 1 2003 01:15:22:937PM | 1030701009 | Steve Wolfe | Shot #9: Full length plasma. Density is still dropping; it seems to be programmed that way. RF seems happy, but we still get this funny bursty behavior. Nominal H-factors are nearly constant~1.1. Notch drops are approx E-port: 1./1.3MW in L 0.9/1.3 in H J : 0.7/1.4 in L, too close to an ELM in H Next shot: flatten the density demand |
| Jul 1 2003 01:32:49:560PM | 1030701010 | Martin Greenwald | Good shot density at about 1.2e20 does transition to nasty looking h-modes after the plasma goes diverted. L-mode phase still looks good |
| Jul 1 2003 01:43:42:280PM | 1030701011 | Martin Greenwald | Good shot slightly lower density H factor still OK H-modes still bad |
| Jul 1 2003 01:58:12:363PM | 1030701013 | Martin Greenwald | Too much density for J-port antenna disrupts early |
| Jul 1 2003 02:12:20:603PM | 1030701013 | Martin Greenwald | Density dropped to 2e20 RF power low in L-mode phase H factors low |
| Jul 1 2003 02:19:07:427PM | 1030701014 | Martin Greenwald | fizzle |
| Jul 1 2003 02:28:18:880PM | 1030701015 | Martin Greenwald | Good Shot RF steady density to 2.2e20 H-factors in L-mode are low H-modes unimpressive |
| Jul 1 2003 02:38:03:703PM | 1030701016 | Martin Greenwald | fizzle |
| Jul 1 2003 02:51:55:023PM | 1030701017 | Martin Greenwald | fizzle |
| Jul 1 2003 03:37:27:080PM | 1030701018 | Martin Greenwald | Good Shot Current to 1.0 MA density about 2.2e20 repeating for next shot, but limited for whole shot |
| Jul 1 2003 03:40:54:613PM | 1030701019 | Martin Greenwald | Good shot limited for whole shot good RF traces nebar ~ 2.2e20 H factors down slightly |
| Jul 1 2003 03:54:11:150PM | 1030701020 | Martin Greenwald | Good Shot nebar to 1.7e20 1 MA |
| Jul 1 2003 04:18:34:657PM | 1030701021 | Martin Greenwald | Good shot nebar to 1.5e20 |
| Jul 1 2003 04:32:29:663PM | 1030701022 | Martin Greenwald | Ip to .6 MA nebar ~ 1e20 H factor up to 1.35 |
| Jul 1 2003 04:34:18:620PM | 1030701023 | Martin Greenwald | Good Shot though lots of trips on RF Ip at 0.6 nebar ~ 1.3e20 |
| Jul 1 2003 04:56:24:200PM | 1030701024 | Martin Greenwald | Good shot density to 1.9 |
| Jul 1 2003 04:57:41:700PM | 1030701025 | Martin Greenwald | fizzle |
| Jul 1 2003 05:13:18:210PM | 1030701026 | Martin Greenwald | density to 2.0 at 0.6 MA Density too high for J, but otherwise OK |
| Physics Operator Comments | |||
| Jul 1 2003 07:43:58:430AM | Bill Rowan | There is an RF problem. The start of this run will be delayed until 10am to allow the engineers to evaluate. | |
| Jul 1 2003 09:05:04:990AM | Bill Rowan | Engineering Setup for Tuesday 07/01/2003 MP#347 C-Mod Performance Evaluation SL: Greenwald PO: Rowan Run starts at 09:00 ECDC in D2 at 2e-4 Torr, stopping by 07:00 Power Systems as on 1030501026 A-coils setup: [+Dtop -Dbot -Jtop +Jbot] Gas setup: fill B-Top with 6 psi D2 Hybrid enabled (PG4) fill B-side lower with 1 psi Ar Hybrid enabled (PG1) fill B-side upper with 10 psi D2 Hybrid DISABLED (PG2) (for ECDC) fill C-side with 30 psi D2 Hybrid enabled (PG3) Enable the following gate valves, assuming no vacuum problems: ECE, DNB, VUV All ICRF transmitters will be needed for this run. Loaded shot 1030501026. Will load segment 1 from yesterday. 1030630004 | |
| Jul 1 2003 09:30:30:500AM | Bill Rowan | set up the a coils for the first shot. Turned on at 0.5s and off at 1.5 s | |
| Jul 1 2003 10:38:37:430AM | Bill Rowan | D is not available. Starting the run without it. | |
| Jul 1 2003 11:05:10:347AM | 1030701001 | Bill Rowan | 001. Plasma. Startup is okay. Discharge looks like a good place to start. Limited on the high field side H/D ratio incorrect. Next shot. No pcs changes. |
| Jul 1 2003 11:32:01:467AM | 1030701002 | Bill Rowan | 002. Plasma. Next shot. Changed clearin from -0.03 m to -0.02 m Increased RCUR by 0.005 at the same time |
| Jul 1 2003 11:45:45:363AM | 1030701003 | Bill Rowan | 003. Plasma elongation is approx 1.4 |
| Jul 1 2003 11:53:21:547AM | 1030701003 | Bill Rowan | Next shot. Leave the initial elongation alone at 1.05 s begin to pull the plasma off the inner wall clearin increased by 0.01 m. rcur increased by 0.005m |
| Jul 1 2003 12:02:42:920PM | 1030701004 | Bill Rowan | 004. Plasma. Does become diverted at approximately 1s The right gap gets a little small. |
| Jul 1 2003 12:04:15:640PM | 1030701004 | Bill Rowan | Next shot. Increase clearin by another 0.01 m |
| Jul 1 2003 12:20:19:087PM | 1030701005 | Bill Rowan | 005. Plasma. Right gap corrected to approximately 1 cm |
| Jul 1 2003 12:20:53:620PM | 1030701005 | Bill Rowan | Next shot. No pcs changes |
| Jul 1 2003 12:34:51:827PM | 1030701006 | Bill Rowan | 006. Plasma Next shot. No pcs changes |
| Jul 1 2003 12:41:55:433PM | 1030701007 | Bill Rowan | 007. Plasma. Disruption at 1.5s. |
| Jul 1 2003 12:47:07:143PM | 1030701007 | Bill Rowan | 007. Plasma. Disruption at 1.5s. Next shot. No pcs changes |
| Jul 1 2003 01:09:38:193PM | 1030701008 | Bill Rowan | 008. Plasma. Disruption at 1.5 s again Next shot. Flatten the density and reduce the nl_04 demand to 6.0e+19 |
| Jul 1 2003 01:10:39:663PM | 1030701009 | Bill Rowan | 009. Plasma. Density still not flat. Next shot. Flatten the density so that is near nebar =1.0e+20 m-3 |
| Jul 1 2003 01:30:09:600PM | 1030701010 | Bill Rowan | 010. Plasma Density is reasonably flat. Next shot. Reduce the density in the first part of the shot. Increase the pre puff from 26 ms to 30 ms to take care of x-ray |
| Jul 1 2003 01:43:09:760PM | 1030701011 | Bill Rowan | 011. Plasma Next shot. Increase nl_04 to 1.5e+20 |
| Jul 1 2003 01:56:53:957PM | 1030701012 | Bill Rowan | 012. Plasma. Disruption at 1.17s Next shot. Reduce the density by approximately 30% |
| Jul 1 2003 02:06:13:297PM | 1030701013 | Bill Rowan | 013. Plasma. Full length. Next shot. No pcs changes. |
| Jul 1 2003 02:12:49:230PM | 1030701014 | Bill Rowan | 014. Fizzle |
| Jul 1 2003 02:16:50:767PM | 1030701014 | Bill Rowan | Next shot. Reduce the prefill fro 30 ms to 26 ms |
| Jul 1 2003 02:29:27:770PM | 1030701015 | Bill Rowan | 015. Plasma. Next shot. Increase IP to 1 MA Slight reduction in density. |
| Jul 1 2003 02:46:19:500PM | 1030701016 | Bill Rowan | 016. Fizzle Next shot. Bz0 may be a little high. Reduced it icef4 from -1320A to -1335A |
| Jul 1 2003 02:57:56:720PM | 1030701017 | Bill Rowan | 017. fizzle Next shot. Raise ICEF$ from -1335 to -1305 This is going in the other direction wrt my previous change |
| Jul 1 2003 03:27:07:000PM | 1030701018 | Bill Rowan | 018. Plasma. Long delay before this shot. There appears to be a vacuum leak. BZ_0 responded as expected. |
| Jul 1 2003 03:33:05:603PM | 1030701018 | Bill Rowan | Next shot. Change the equilibrium to remain limited throughout the shot. |
| Jul 1 2003 03:33:38:337PM | 1030701018 | Bill Rowan | |
| Jul 1 2003 03:56:21:187PM | 1030701019 | Bill Rowan | 019. Plasma. Limited on the inner wall. Next shot. Reduce nl_04 demand from 0.9e+20 to 0.6e+20 |
| Jul 1 2003 03:55:44:667PM | 1030701020 | Bill Rowan | 020. Plasma Next shot. Reducet the nl_04 demand from 0.6e+20 to 0.45e+20 |
| Jul 1 2003 04:10:49:143PM | 1030701021 | Bill Rowan | 021. Plasma. Next shot. 0.6 MA |
| Jul 1 2003 04:21:43:833PM | 1030701022 | Bill Rowan | 022. Plasma. Next shot. Increased nl_04 demand from 4.5e+19 to 7.0e+19 |
| Jul 1 2003 04:24:04:587PM | 1030701022 | Bill Rowan | Increase the prefill from 26 ms to 30 ms |
| Jul 1 2003 04:35:00:120PM | 1030701023 | Bill Rowan | 023. Plasma Next shot. Further increase in nl_04 demand from 7.0e+19 to 9e+19 |
| Jul 1 2003 04:51:31:580PM | 1030701024 | Bill Rowan | 024. Plasma Next shot. Further increased in nl_04 demand from 9e+19 to 1.1e+20 |
| Jul 1 2003 04:59:30:797PM | 1030701025 | Bill Rowan | 025. Fizzle Next shot. Decrease the prefill from 30 ms to 26 ms |
| Engineering Operator Comments | ||||
| Shot | Time | Type | Status | Comment |
| 1 | 10:51:11:043AM | Plasma | Ok | |
| 2 | 11:18:29:040AM | Plasma | Ok | |
| 3 | 11:38:42:290AM | Plasma | Ok | |
| 4 | 11:55:00:970AM | Plasma | Ok | |
| 5 | 12:08:29:053PM | Plasma | Ok | |
| 6 | 12:22:25:577PM | Plasma | Ok | |
| 7 | 12:35:52:563PM | Plasma | Ok | |
| 8 | 12:49:27:977PM | Plasma | Ok | |
| 9 | 01:02:26:963PM | Plasma | Ok | |
| 10 | 01:16:02:487PM | Plasma | Ok | |
| 11 | 01:30:52:383PM | Plasma | Ok | |
| 12 | 01:44:13:467PM | Plasma | Ok | |
| 13 | 01:57:52:767PM | Plasma | Ok | |
| 14 | 02:10:31:880PM | Plasma | Ok | |
| 15 | 02:23:14:323PM | Plasma | Ok | |
| 16 | 02:36:08:403PM | Plasma | Ok | |
| 17 | 02:49:36:800PM | Plasma | Ok | |
| 18 | 03:22:23:040PM | Plasma | Ok | |
| 19 | 03:35:15:277PM | Plasma | Ok | |
| 20 | 03:48:24:627PM | Plasma | Ok | |
| 21 | 04:01:12:317PM | Plasma | Ok | |
| 22 | 04:16:06:183PM | Plasma | Ok | |
| 23 | 04:29:18:390PM | Plasma | Ok | |
| 24 | 04:42:10:880PM | Plasma | Ok | |
| 25 | 04:55:35:730PM | Plasma | Ok | |
| 26 | 05:08:37:407PM | Plasma | Ok | |