| Miniproposals | ||||||||||
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| Operators | |
| Session leader(s): | J. Randall Wilson |
| Physics operator(s): | Earl Marmar |
| Engineering operator(s): | Bill Cochran,Sam Pierson,Gary Dekow |
| Engineering Operator Run Comment |
| automatically entered by signon - please replace with real comment |
| Session Leader Plans |
| Entered: Aug 27 2007 04:15:30:480PM |
| Author: J. Randall Wilson |
| Session Leader Plan for Run 1070828
MP 515: Effect of launched LH wave n_par spectrum on current profile Session Leader: J.R. Wilson Physop: R. Parker The purpose of these experiments is to investigate the effect of varying the launched n|| spectrum on the LH-perturbed current distribution in C-Mod plasmas. The measurements will be carried out in both Ohmic and ICRF-heated L-Mode plasmas, as well as in H-Mode plasmas providing suitable low density H-Modes can be produced. Overnight ECDC, usual formula. Power systems as on 1070827009 A-coil configuration: normal [Dtop -Dbot -Jtop +Jbot] and 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) leave NINJA as is DISABLED Enable the following gate valves and shutters: ECE, VUV, Z-bolo shutters, NB Torvac setup: Gate valves open during pulse. ICRF: E-port ready at beginning of run; also J-port if feasible Starting shot: 1070827009 Following the advice of the EPC, we'll concentrate on n|| scans in the run: Shots 1-5: Establish 800 kA, 5.4 T, 5e19 m-3 discharge. Couple �?�500 kW LHCD @ n|| = 1.6. Ensure plasma stays in L-Mode with available ICRF power (J-port preferred but if not, E-port is OK), Optimize shape for coupling. Shots 6-10: No ICRH. Obtain good quality MSE and IXS data on shot established in shots 1-5. Shots 11-15: Repeat shots 6-10 with ICRH = 1 MW and higher if available. Shots 16-20: Couple �?�500 kW LHCD @ n|| = 2.3. No ICRH. Obtain good quality MSE and IXS data. Shots 21-25: Repeat shots 16-20 with 1 MW and higher if available, avoiding H-Mode. Shots 25 - end of run: Repeat above shot sequence beginning with shot 16, with n|| = 3.1. Note: If ICRF part of plan is unproductive, stick with Ohmic and increase n to 8e19 m-3. |
| Physics Operators Plans |
| Entered: Aug 27 2007 05:32:45:910PM |
| Author: Earl Marmar |
| Engineering setup for Tuesday, 28 Aug 2007
MP 515: Effect of launched LH wave n_par spectrum on current profile Session Leader: J.R. Wilson Physop: E. Marmar Run is scheduled to begin at 9:00 am and end at 5:00 pm (EDT) The purpose of these experiments is to investigate the effect of varying the launched n|| spectrum on the LH-perturbed current distribution in C-Mod plasmas. The measurements will be carried out in both Ohmic and ICRF-heated L-Mode plasmas, as well as in H-Mode plasmas providing suitable low density H-Modes can be produced. Overnight ECDC in deuterium (2e-4 gauge) standard sweep Power systems as on 1070827019 A-coil configuration: normal [Dtop -Dbot -Jtop +Jbot] and 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) leave NINJA as is DISABLED Enable the following gate valves and shutters: ECE, VUV, Z-bolo shutters, DNB Torvac setup: Gate valves open during pulse. ICRF: E-port and J-port ready for first plasma LHRF: ready for first plasma Starting shot: 1070827019 nl_04 target to 0.5e20 All usual diagnostics, including DNB. MSE and hard x-ray imaging particularly important for this run. |
| Session Leader Summaries |
| Entered: Aug 28 2007 05:48:12:710PM |
| Author: Ron Parker |
| The purpose of the run was to drive current with LH waves launched at various n_par's, and to measure the resulting current profile, to the extent possible, with MSE. As usual hard X-Rays were monitored and their profiles will be compared with the j-profile inferred from MSE.
The run was partially successful, with LHCD applied to both 800 kA and 1 MA discharges. The density was kept low in order to maximize the driven current. The maximum coupled power was ~ 700 kw, and the maximum deltaV/V was ~ 50%. It appeared that the driven current may have been somewhat closer to the edge than expected, judging from the rapid response of the loop voltage. It will be interesting to compare with shots from July 2006. Other effects noted: both stabilization and destabilization of a tearing mode, e.g., shot 4 where the TM was excited and shot 15 where a tearing mode seemed to be suppressed. (See entries under MHD by S. Wolfe). Also, in the case of the largest voltage drop, the sawtooth inversion radius contracted by 3-4 FRC channels . Complete sawtooth stabilization did not occur on any shot. The current drive efficiency seems to have degraded somewhat from last year. Thus, with 700 kW it was only possible to reduce the loop voltage by a factor of 2, whereas last year with 800 kW it was possible to at least transiently reverse the loop voltage. It may be that the n_par spectrum has been somewhat modified by the effects of many arcs during this campaign. Hopefully there will be an opportunity to measure the n_par spectrum if the launcher can be removed at the end of the campaign. One part of the MP was not accomplished, namely combining LHCD with ICRH and investigating the driven current profile at higher temperature. As anticipated, the ICRF caused a density rise that reduced LHCD efficiency and coupling. Next time this is attempted, the ICRF should be applied first and the outer gap adjusted for optimal coupling before turning on the LH. There was not sufficient time to try this in this run. |
| Physics Operator Summaries |
| Session Leader Comments | |||
| Aug 28 2007 09:06:00:127AM | 1070828001 | Ron Parker | Randy is SL but I'll also make comments under SL in logbook.
Note that Earl is PO. Starting with 85 kW per klystron, except 4&5 which are at 75 kW, and 90 deg ideal phasing. |
| Aug 28 2007 09:16:33:453AM | 1070828001 | J. Randall Wilson | 450 kW LH from 0.7 to 1.0 sec
next move to 0.9 to 1.2 s to help MSE |
| Aug 28 2007 09:19:06:770AM | 1070828001 | Ron Parker | Pretty good shot, LH did not trip, delta vloop ~ 0.2 V
Next: move LH to 0.9 s starting time. |
| Aug 28 2007 09:39:43:397AM | 1070828002 | Ron Parker | Shot was OK, breakdown in WG 5 lower caused trip.
Coupling was not as good as on first shot due to lower density at grill. Next: reduce outer gap by 4 mm. |
| Aug 28 2007 09:40:18:647AM | 1070828002 | J. Randall Wilson | moved to 0.9 s
one drop-out on LH reflection higher due to lower density in front of grill but loop voltage drop as large |
| Aug 28 2007 10:04:12:710AM | 1070828003 | Ron Parker | Shot 3 was OK, but still one trip and breakdown in the launcher.
Coupling better, but still 30% reflected power. DeltaV/V ~25%, but relatively fast response on loop voltage. No clear change on MSE. |
| Aug 28 2007 10:21:24:000AM | 1070828003 | J. Randall Wilson | added 0.04 s to pulse width at MSE request
one arc |
| Aug 28 2007 10:21:14:220AM | 1070828004 | Ron Parker | Shot was good, no trip, 20-30% deltaV/V.
Next:tease power up a bit. Steve reports stong tearing mode appears during LH. |
| Aug 28 2007 10:21:35:453AM | 1070828004 | J. Randall Wilson | clean shot |
| Aug 28 2007 10:41:40:103AM | 1070828005 | Ron Parker | Shot 5 dropped out at 1.2 s, due to window arc.
Still clear deltaV/V ~ 25-35%. Power ~ 500 kW. |
| Aug 28 2007 10:42:38:680AM | 1070828005 | J. Randall Wilson | arc near end back by tube 9 |
| Aug 28 2007 10:56:59:690AM | 1070828006 | Ron Parker | Shot 6 was best so far
Try to get a little more power (~ 15%) on next shot. |
| Aug 28 2007 11:21:09:757AM | 1070828008 | Ron Parker | Pretty good shot, almost 600 kW coupled, no dropouts.
Next: 1 MW from J port, 1-1.2 s. |
| Aug 28 2007 11:55:12:670AM | 1070828009 | Ron Parker | Shot 9 was good, clear MSE effect and no dropouts.
Next: Can we get a little more power? |
| Aug 28 2007 12:08:37:767PM | 1070828010 | Ron Parker | Shot 10 had LH dropout, useful for MSE cmparison.
Next: reduce klystron 8 power by 15 kW |
| Aug 28 2007 12:20:48:550PM | 1070828011 | Ron Parker | Good shot, full length LH. Sawteeth region narrows a bit.
Next: 1 MW from J port. |
| Aug 28 2007 12:32:29:993PM | 1070828012 | Ron Parker | Shot 12 had 1 MW ICRH, but LH tripped out possibly due to H-Mode. |
| Aug 28 2007 12:54:23:590PM | 1070828013 | Ron Parker | ICRF again tripped out LH.
Next: 75 deg phasing, no ICRH |
| Aug 28 2007 12:59:58:160PM | 1070828014 | Ron Parker | Shot 14 ran well with ~ 700 kw coupled.
deltaV/V~ 30-40%. Next: reduce nl_04 to 4e19. |
| Aug 28 2007 01:13:18:600PM | 1070828015 | Ron Parker | Repeat of shot 14 with slightly lower density. DeltaV/V ~ 50%, although LH tripped and did not recover after 1.1s |
| Aug 28 2007 01:22:27:647PM | 1070828016 | Ron Parker | Shot 16 had LH trip @ 0.95 s and did not recover. |
| Aug 28 2007 01:36:39:060PM | 1070828017 | Ron Parker | Shot 17 disrupted. |
| Aug 28 2007 02:36:00:870PM | 1070828018 | Ron Parker | Good shot, full length LH, 700 kW, deltaV/V ~ 40-50%. Best shot today so far for LH. |
| Aug 28 2007 02:23:13:490PM | 1070828019 | Ron Parker | Shot 19 was 60 deg phasing. A few trips. |
| Aug 28 2007 02:23:54:163PM | 1070828020 | Ron Parker | Shot 20 was a good 60 deg shot. early trip but recovered from 0.95 to 1.25 s. |
| Aug 28 2007 02:34:15:150PM | 1070828021 | Ron Parker | Shot 21 disrupted. Attempting to couple to 1 MA discharge. |
| Aug 28 2007 03:06:10:400PM | 1070828023 | Ron Parker | Shot 23 was a good shot, but LHCD was weak! Maybe due to density rise. |
| Aug 28 2007 03:20:40:390PM | 1070828024 | Ron Parker | Shot 24 was good, LH dropped out at 1.15s and did not recover.
Phasing was 75 deg, to improve penetration. |
| Aug 28 2007 03:37:11:243PM | 1070828025 | Ron Parker | Shot 25 was not very good, and disrupted on rampdown. High noise level on reflected power. |
| Aug 28 2007 03:37:35:120PM | 1070828026 | Ron Parker | Shot 25 fizzled. |
| Aug 28 2007 04:31:08:610PM | 1070828029 | Ron Parker | Shot 29 was a good shot, deltaV/V ~ 0.5. But compared to last July, not as efficient. |
| Aug 28 2007 05:01:36:780PM | 1070828031 | Ron Parker | Shot 31 went off, stepped phase -- 60,75,90,75,60 |
| Aug 28 2007 05:17:41:727PM | 1070828032 | Ron Parker | On this shot we tried to step the LH power up after 1 s, but no luck after several retries. The deltaV/V was ~ 50 % from 0.9-1.0 s. Phasing= 75 deg. |
| Physics Operator Comments | |||
| Aug 28 2007 09:15:52:720AM | 1070828001 | Earl Marmar | load from 1070827019
nl_04 target to 0.5e20 plasma nl_04 between .5 and .6e20 LH pulse steady at .4 MW |
| Aug 28 2007 09:40:40:960AM | 1070828002 | Earl Marmar | no pcs changes
plasma |
| Aug 28 2007 09:58:49:410AM | 1070828003 | Earl Marmar | increase RCUR 2mm (to decrease outer gap 4 mm)
plasma efit shows outer gap now about 2 mm some early hards |
| Aug 28 2007 10:21:19:923AM | 1070828004 | Earl Marmar | increase prefill puff by 1 msec (now 22 msec)
increase RXU 5mm plasma early hards are worse, current rise looks ratty around 0.2 seconds |
| Aug 28 2007 10:28:09:053AM | 1070828005 | Earl Marmar | increase prefill 1 msec (now 23 msec)
increase early segment 2 nl_04 program, still asking for 5e19 in flattop plasma early hards a little better, but still there |
| Aug 28 2007 11:06:00:077AM | 1070828006 | Earl Marmar | increase prefill 1 msec (now 24 msec)
increase early segment 2 nl_04 program again, still asking for 5e19 in flattop plasma |
| Aug 28 2007 11:05:45:187AM | 1070828007 | Earl Marmar | no pcs changes
plasma |
| Aug 28 2007 11:24:24:420AM | 1070828008 | Earl Marmar | no pcs changes
plasma |
| Aug 28 2007 11:49:43:567AM | 1070828009 | Earl Marmar | no pcs changes
some delay before the shot for computer issues plasma |
| Aug 28 2007 12:00:41:787PM | 1070828010 | Earl Marmar | no pcs changes
plasma |
| Aug 28 2007 12:33:11:243PM | 1070828011 | Earl Marmar | turn on active mhd in dpcs
plasma |
| Aug 28 2007 12:33:21:010PM | 1070828012 | Earl Marmar | no pcs changes
plasma |
| Aug 28 2007 12:57:15:077PM | 1070828013 | Earl Marmar | increase prefill puff 1 msec (now 25 msec)
plasma |
| Aug 28 2007 12:57:33:547PM | 1070828014 | Earl Marmar | no pcs changes
plasma |
| Aug 28 2007 01:07:30:670PM | 1070828015 | Earl Marmar | nl_04 target to 4e19
plasma |
| Aug 28 2007 01:29:40:267PM | 1070828016 | Earl Marmar | increase RCUR 1 mm (to decrease outer gap 2 mm)
plasma current rise after 0.14 seconds is looking ragged density lurching around, up to 0.6e19 at start of LH pulse |
| Aug 28 2007 01:36:29:090PM | 1070828017 | Earl Marmar | increase prefill puff 1 msec (now 26 msec)
plasma big injection at 0.39 s, disrupts shortly after |
| Aug 28 2007 01:59:42:377PM | 1070828018 | Earl Marmar | reduce prefill puff 2 msec (now 24 msec)
plasma |
| Aug 28 2007 02:04:20:930PM | 1070828019 | Earl Marmar | no pcs changes
plasma more early hards |
| Aug 28 2007 02:23:50:053PM | 1070828020 | Earl Marmar | add 3 msec to prefill puff (now 27 msec)
decrease RCUR 1 mm (to increase outer gap 2 mm) plasma |
| Aug 28 2007 02:37:37:823PM | 1070828021 | Earl Marmar | increase RCUR 1 mm (to decrease outer gap 2 mm)
Ip to 1.0 MA plasma ugly current ramp, early disruption |
| Aug 28 2007 02:48:53:717PM | 1070828022 | Earl Marmar | decrease prefill puff 2 msec (now 25 msec)
slow down the current rise, still aiming for 1MA fizzle |
| Aug 28 2007 03:08:02:950PM | 1070828023 | Earl Marmar | no pcs changes
plasma nice 1MA target, nl_04=4e19 at LH turnon; density rises to 6e19 during LH |
| Aug 28 2007 03:06:58:260PM | 1070828024 | Earl Marmar | add 2 msec to prefill puff (now 27 msec) |
| Aug 28 2007 03:34:46:680PM | 1070828025 | Earl Marmar | nl_04 target to 3.5e19
plasma disrupt in rampdown |
| Aug 28 2007 03:37:36:683PM | 1070828026 | Earl Marmar | decrease prefill puff 3 msec (now 24 msec)
add a gas puff after 1.5 seconds fizzle |
| Aug 28 2007 03:53:21:283PM | 1070828027 | Earl Marmar | no pcs changes
fizzle |
| Aug 28 2007 04:07:54:090PM | 1070828028 | Earl Marmar | decrease prefill puff 3 msec (now 21 msec)
fizzle |
| Aug 28 2007 04:29:47:327PM | 1070828029 | Earl Marmar | add .5 mT to BR_0 offset
plasma |
| Aug 28 2007 04:47:22:663PM | 1070828030 | Earl Marmar | reduce prefill puff 4 msec (now 17 msec)
Ip to .8 MA fizzle |
| Aug 28 2007 04:58:46:650PM | 1070828031 | Earl Marmar | BR_0 offset .5 mT more negative
plasma |
| Aug 28 2007 05:15:20:427PM | 1070828032 | Earl Marmar | increase prefill puff 2 msec(now 19 msec)
turn off the late (after 1.5 s) gas puff plasma lithium pellet (1.5 seconds), then disrupt |
| Engineering Operator Comments | ||||
| Shot | Time | Type | Status | Comment |
| 1 | 09:07:13:657AM | Plasma | Ok | |
| 2 | 09:29:45:833AM | Plasma | Ok | |
| 3 | 09:47:31:203AM | Plasma | Ok | |
| 4 | 10:07:01:463AM | Plasma | Ok | |
| 5 | 10:21:57:517AM | Plasma | Ok | |
| 6 | 10:42:01:103AM | Plasma | Ok | |
| 7 | 10:57:10:423AM | Plasma | Ok | |
| 8 | 11:11:10:757AM | Plasma | Ok | |
| 9 | 11:36:30:453AM | Plasma | Ok | |
| 10 | 11:54:24:917AM | Plasma | Ok | |
| 11 | 12:07:25:953PM | Plasma | Ok | |
| 12 | 12:20:42:147PM | Plasma | Ok | |
| 13 | 12:33:26:447PM | Plasma | Ok | |
| 14 | 12:46:01:340PM | Plasma | Ok | |
| 15 | 01:00:47:440PM | Plasma | Ok | |
| 16 | 01:16:18:183PM | Plasma | Ok | |
| 17 | 01:30:31:800PM | Plasma | Ok | |
| 18 | 01:44:45:883PM | Plasma | Ok | |
| 19 | 01:59:00:797PM | Plasma | Ok | |
| 20 | 02:16:42:323PM | Plasma | Ok | |
| 21 | 02:30:35:250PM | Plasma | Ok | |
| 22 | 02:43:20:380PM | Plasma | Ok | |
| 23 | 02:55:58:087PM | Plasma | Ok | |
| 24 | 03:09:04:590PM | Plasma | Ok | |
| 25 | 03:21:50:283PM | Plasma | Ok | |
| 26 | 03:35:38:570PM | Plasma | Ok | |
| 27 | 03:49:21:920PM | Plasma | Ok | |
| 28 | 04:03:16:957PM | Plasma | Ok | |
| 29 | 04:15:35:180PM | Plasma | Ok | |
| 30 | 04:31:25:157PM | Plasma | Ok | |
| 31 | 04:46:30:803PM | Plasma | Ok | |
| 32 | 05:09:39:357PM | Plasma | Ok | |
| System Availability | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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