| Miniproposals | ||||||||||
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| Operators | |
| Session leader(s): | Jim Terry,Jim Terry |
| Physics operator(s): | Jim Irby |
| Engineering operator(s): | Gary Dekow,Bill Cochran,Frank Silva |
| Engineering Operator Run Comment |
| MP#223,224/Irby, Silva |
| Session Leader Plans |
| Physics Operators Plans |
| Session Leader Summaries |
| Entered: Jul 7 2004 03:49:21:053PM |
| Author: To Be Determined |
| Session Leader's summary of run 990901 MP#223 and #224 - "Recombination and Ionization in the C-Mod Divertor" and "Measurement of the plasma parameters and their scalings in recombining regions of Alcator C-Mod". Physics Operator: Jim Irby Session Leader: Jim Terry The run was successful in accomplishing the following goals: 1) measuring the spatial extent and magnitude of the volume recombination over a range of densities and "degrees" of detachment 2) measuring the effect of the bypass flaps on the detachment threshold (their state had no effect on the threshold) (shots 8 (CLOSED) - 9 (OPEN), and shots 16 (OPEN) - 17,18 (CLOSED)) 3) measuring the effect of the bypass flaps on the main plasma fueling rate (shots 8 (CLOSED) - 9 (OPEN), and shots 16 (OPEN) - 17,18 (CLOSED)), 4) measuring the effect of N_2 impurity puffs on the detachment characteristics (shots 20 and 21) Setup: Toroidal Field: 5.4 T Plasma Current: 1.0 MA Working gas species: D2 N2 available D2 available for NINJA Density: multiple, up to ne0_TCI=4.7x10^20 m-3 General Plan: On shots 001 thru 008 the maximum density is raised in steps of ~0.5x1020 m-3 from ne=2.0x1020 m-3 on shot 002 to ne=4.7x1020 m-3 on shot 008. At peak densities of ne=4.7x1020 m-3, the detachment thresholds and the density rises were compared for shots with the flaps OPEN (009) and CLOSED (008). At peak densities of ne=3.7-4.0x1020 m-3, the detachment thresholds and the density rises were compared for shots with the flaps OPEN (016) and CLOSED (015,017,018,019). Puff N_2 to cool the divertor plasma, investigate the effects on detachment (020 and 021). A detailed accounting follows: 001 Good shot - except that strike points are not being held const. The outer strike pt moves up to about probe 6. nl_04 =1.34e20 Ne0_TCI=2.5e20 @ 1 s 002 Good shot - strike points are more const. The outer strike pt is between probe 4 and 5. nl_04 =1.04e20 Ne0_TCI=1.93e20 003 Good shot - strike points drift up somewhat. The outer strike pt moves up from probe 4 to 5. nl_04 =1.47e20 Ne0_TCI=2.58e20 at 1 s no detachment 004 Good shot - strike points still drifting up. The outer strike pt moves up from probe 4 to 6. nl_04 =1.78e20 Ne0 (based on NL_04) is probably ~3.5 e20 at 1 s detachment on probe 5 (separatrix) finished by 0.8 005 Good shot - good strike point control. The outer strike pt on probe 4. nl_04 =1.75e20 rising to 2.0 Ne0_TCI=3.87e20 at 1.15 s detachment (as determined by TV) at about 1.05 s, probes show it earlier Divertor camera shows the detachment. 006 Good shot - good strike point control. The outer strike pt on probe 5. nl_04 =rising to 2.15e20 Ne0_TCI=4.4e20 at 1 s detachment at about .8 s, 007 Good shot - repeat of last shot nl_04 =2.08e20 Ne0 _TCI=4.4e20 at 1 s CAMAC problems Good fast edge fluctuation signal looking at D_2 puff at A-B limiter 008 Good shot - a repeat of last shot nl_04 rises to 2.27 at 1 s Ne0_TCI=4.7e20 at 1 s detachment between 0.8 and 0.9 s, Capillary puff was on the inner midplane, rather than at the A-B limiter 009 Good shot - a repeat of last shot BUT WITH THE FLAPPERS OPEN nl_04 rises to 2.27 at 1 s Ne0_TCI=4.75e20 at 1 s detachment is earlier than with the flaps closed, between 0.6 and 0.7 s, but this is at about the same density - implying that the detachment threshold is not affected by the flaps, they just allow a faster density rise. Capillary puff was at the A-B limiter 010 Odd shot - although this was supposed to be a repeat of last shot BUT WITH THE FLAPPERS CLOSED, however it was a vastly different shot. It appears as if the plasma is poloidally detached most of the shot. nl_04 rises to 2.25 at 0.7 s Ne0_TCI=4.4e20 at 1 s Capillary puff was at the A-B limiter This shot should not be taken as representative. Disrupted at 1.39 s 011 fizzle 012 not usable - something happens at 0.9 s which ultimately leads to a disruption at 1.18 s 013 not usable - poor current and density rise - probably a poloidal detachment around 0.4 s 014 Good shot -dropped the density back down to nl_04 of 1.37e20. Ne0_TCI~2e20 no detachment 015 Good shot -ramped the density to nl_04 of 1.95e20 at 1.25 s. Ne0_TCI=3.9e20 at 1.25 s Detachment on probes occurs from 0.85 to 0.95 s Outer strike pt is on probe 5 The flappers were closed. 016 Good shot - Repeat of the last shot, BUT WITH THE FLAPS OPEN the density got to nl_04 of 2.07e20 at 1.15 s. Ne0_TCI=4.25e20 at 1 .15 s Detachment on probes occurs from 0.6 to 0.7 s, ie earlier than on shot 015. Detachment occurs at an NL_05 between 1.55 and 1.75e20 Outer strike pt is on probe 5 017 Good shot - Repeat of the last shot, BUT WITH THE FLAPS CLOSED, ie just like 015 In fact it is just like 015. - with the density going to nl_04 of 1.95e20 at 1.15 s. Ne0=3.7e20 at 1.15 s Detachment on probes occurs from 0.7 to 0.9 s. Detachment occurs at an NL_05 between 1.55 and 1.8e20 Outer strike pt is on probe 5 018 Good shot - Repeat of the last shot - but with 1st attempt at an N_2 puff - saw no nitrogen from puff 019 Good shot - Repeat of the last shot - but with 2nd attempt at an N_2 puff - small or no nitrogen from puff. This implies that B_side_upper is not opening Inner probe 3 detachs at 0.65 s, inner probe 4 at 1 s. 020 Good shot - Repeat, but moved N_2 puff to B side lower. 50 ms puff - saw it. McPherson looking at Lyman_alpha and Li-like N. No change in detachment characteristics. 021 Good shot - Repeat, but with 3 N_2 puffs - disrupts after the 3rd puff Deep detachment - 2nd puff also detachs the inner divertor completely 2nd puff affects density - Ne0_TCI=4.2e20 at .91 s 022 disrupted at 0.73s |
| Physics Operator Summaries |
| Entered: Jul 7 2004 04:37:09:190PM |
| Author: To Be Determined |
| Physop Run Summary for 990901 ----------------------------------------------------------------- MP#223 and #224 Recombination and Ionization in the C-Mod Divertor and Measurement of the Plasma Parameters and Their Scalings in Recombining Regions of Alcator C-Mod SL: Terry EO: Silva, Cochran, Dekow PO: Irby Run should begin at 9:00AM and end at 5:00PM. ICRF will piggyback as possible at the end of flattop, to continue conditioning of J3 and J4. Engineering setup: *** Two hours of ECDC in D2 prior to the run. *** We will run 5.4T shots at 1.0 and possibly 0.8 MA. Setup power supplies from 990826002 Gas setup - fill B-top with 6 psi of D2 Hybrid enabled fill B-side lower with 1 psi of Ar Hybrid DISABLED fill B-side upper with 6 psi of N2 Hybrid DISABLED fill C-side with 30 psi of D2 Hybrid enabled leave J-bottom as is Hybrid DISABLED The following gate valves should be enabled, assuming no vacuum problems: ECE, VUV. ----------------------------------------------------------------- Results: Machine ran extremely well again today except when we tried to push the density too high or puff too much nitrogen. At the highest densities the plasma detached (MARFed??) and seemed to ingest bits of the wall (mostly carbon). Problems: At the highest densities we were railing OH1 at its 27kA limit. Also had a case or two of EF1U railing. Lost magnetics data on a couple of shots. We should investigate replacing the TRAQ modules. B_side_lower had not been used for several weeks and did not work today. We had to switch to B_side_lower to get our N2 puffs. ----------------------------------------------------------------- 21 plasmas 1 fizzle --------- 22 shots |
| Session Leader Comments | |||
| Sep 1 1999 10:19:50:467AM | Jim Terry | The run plan for 990901 is described in MPs 223 and 224 - "Recombination and Ionization in the C-Mod Divertor" and "Meas. of the plasma parameters and their scalings in recombining regions of Alcator C-Mod". The basic plan is to run with a series of density ramps, ultimately reaching deep divertor detachment and densities of ~4.5e20 m^-3. The flappers will be used on some of the shots. Setup: Toroidal Field: 5.4 T Plasma Current: 1.0 MA Working gas species: D2 ****N2 available thru B-side upper**** D2 available for NINJA Density: multiple, up to ne=4.5x10^20 m -3 Load shot 990826002. It has constant strike points, mostly between outer probes 3 and 4 and at inner probe 1. Plan: 5 ohmic shots in which the maximum density is raised in steps of 0.5x1020 m -3 from ne=2.0x1020 m -3 on shot 1 to ne=4.5x1020 m-3 on shot 5. 5 shots having a peak density of ne=4.5x1020 m -3. Open various combinations of flappers ~ 100 ms after the maximum density has been reached. 5 shots at lower density (ne=2x1020 m -3) and with no RF, but puffing N2 to cool the divertor plasma. Reserve option to raise or ower the current in order to raise the density or deepen the detachment. | |
| Sep 2 1999 09:07:28:217AM | 990901001 | Jim Terry | Good shot - except that strike points are not being held const. The outer strike pt moves up to about probe 6. nl_04 =1.34e20 Ne0_TCI=2.5e20 @ 1 s Divertor camera pictures are dim. |
| Sep 2 1999 09:09:11:107AM | 990901002 | Jim Terry | Good shot - strike points are more const. The outer strike pt is between probe 4 and 5. nl_04 =1.04e20 Ne0_TCI=1.93e20 Divertor camera images show a brighter inner nose. Good Lyman spectrum. |
| Sep 2 1999 09:22:06:577AM | 990901003 | Jim Terry | Good shot - strike points drift up somewhat. The outer strike pt moves up from probe 4 to 5. nl_04 =1.47e20 Ne0_TCI=2.58e20 at 1 s no detachment though Divertor camera images show more light on outer leg. Good Lyman spectrum. |
| Sep 2 1999 09:44:17:437AM | 990901004 | Jim Terry | Good shot - strike points still drifting up. The outer strike pt moves up from probe 4 to 6. nl_04 =1.78e20 Ne0 (based on NL_04) is probably ~3.5 e20 at 1 s detachment on probe 5 (separatrix) finished by 0.8 |
| Sep 2 1999 09:48:22:013AM | 990901005 | Jim Terry | Good shot - good strike point control. The outer strike pt on probe 4. nl_04 =1.75e20 rising to 2.0 Ne0_TCI=3.87e20 at 1.15 s detachment (as determined by TV) at about 1.05 s, probes show it earlier Divertor camera shows the detachment. Good Lyman spectrum. |
| Sep 2 1999 09:49:22:170AM | 990901006 | Jim Terry | Good shot - good strike point control. The outer strike pt on probe 5. nl_04 =rising to 2.15e20 Ne0_TCI=4.4e20 at 1 s detachment at about .8 s, Divertor camera shows the detachment. Good Lyman spectrum. |
| Sep 2 1999 10:02:35:560AM | 990901007 | Jim Terry | Good shot - repeat of last shot nl_04 =2.08e20 Ne0 _TCI=4.4e20 at 1 s CAMAC problems Good fast edge fluctuation signal looking at D_2 puff at A-B limiter |
| Sep 2 1999 10:04:18:390AM | 990901008 | Jim Terry | Good shot - a repeat of last shot nl_04 rises to 2.27 at 1 s Ne0_TCI=4.7e20 at 1 s detachment between 0.8 and 0.9 s, Divertor camera shows the detachment. Good Lyman spectrum. Capillary puff was on the inner midplane, rather than at the A-B limiter |
| Sep 2 1999 10:05:31:217AM | 990901009 | Jim Terry | Good shot - a repeat of last shot BUT WITH THE FLAPPERS OPEN nl_04 rises to 2.27 at 1 s Ne0_TCI=4.75e20 at 1 s detachment is earlier than with the flaps closed, between 0.6 and 0.7 s, but this is at about the same density - implying that the detachment threshold is not affected by the flaps, they just allow a faster density rise. Divertor camera shows the detachment. Good Lyman spectrum. Capillary puff was at the A-B limiter |
| Sep 2 1999 10:25:11:937AM | 990901010 | Jim Terry | Odd shot - although this was supposed to be a repeat of last shot BUT WITH THE FLAPPERS CLOSED, however it was a vastly different shot. It appears as if the plasma is poloidally detached most of the shot. nl_04 rises to 2.25 at 0.7 s Ne0_TCI=4.4e20 at 1 s Capillary puff was at the A-B limiter This shot should not be taken as representative. Disrupted at 1.39 s |
| Sep 1 1999 02:16:42:623PM | 990901011 | Jim Terry | fizzle |
| Sep 1 1999 02:18:32:030PM | 990901012 | Jim Terry | Not a usable shot - the current and density rise are OK, but something happens at 0.9 s which ultimately causes a disruption at 1.18 s |
| Sep 1 1999 02:20:33:543PM | 990901013 | Jim Terry | Not a usable shot - the current and density rise are not good, ultimately nl_04 reaches flattop at 2.0e20. Lots of inner wall light around 0.4 s. |
| Sep 2 1999 10:31:27:547AM | 990901014 | Jim Terry | Good shot -dropped the density back down to nl_04 of 1.37e20. Ne0_TCI~2e20 no detachment |
| Sep 2 1999 10:32:46:607AM | 990901015 | Jim Terry | Good shot -ramped the density to nl_04 of 1.95e20 at 1.25 s. Ne0_TCI=3.9e20 at 1.25 s Detachment on probes occurs from 0.85 to 0.95 s Outer strike pt is on probe 5 The flappers were closed. |
| Sep 2 1999 10:35:35:920AM | 990901016 | Jim Terry | Good shot - Repeat of the last shot, BUT WITH THE FLAPS OPEN the density got to nl_04 of 2.07e20 at 1.15 s. Ne0_TCI=4.25e20 at 1 .15 s Detachment on probes occurs from 0.6 to 0.7 s, ie earlier than on shot 015. Detachment occurs at an NL_05 between 1.55 and 1.75e20 Outer strike pt is on probe 5 |
| Sep 2 1999 10:37:16:543AM | 990901017 | Jim Terry | Good shot - Repeat of the last shot, BUT WITH THE FLAPS CLOSED, ie just like 015 In fact it is just like 015. - with the density going to nl_04 of 1.95e20 at 1.15 s. Ne0=3.7e20 at 1.15 s Detachment on probes occurs from 0.7 to 0.9 s. Detachment occurs at an NL_05 between 1.55 and 1.8e20 Outer strike pt is on probe 5 |
| Sep 1 1999 04:01:12:797PM | 990901018 | Jim Terry | Good shot - Repeat of the last shot - but with 1st attempt at an N_2 puff - saw nothing |
| Sep 2 1999 10:41:35:513AM | 990901019 | Jim Terry | Good shot - Repeat, 2nd try at the N_2 puff, but saw nothing. Ne0_TCI=3.6e20 at 1 s. This means that the B side upper is not opening. McPherson looking at Lyman_alpha and Li-like N. |
| Sep 1 1999 04:45:12:997PM | 990901020 | Jim Terry | Good shot - Repeat, but moved N_2 puff to B side lower. 50 ms puff - saw it - 60 kW on 2pi radiation bolo. McPherson looking at Lyman_alpha and Li-like N. No change in detachment characteristics. |
| Sep 2 1999 10:43:39:577AM | 990901021 | Jim Terry | Good shot - Repeat, but with 3 N_2 puffs - disrupts after the 3rd puff Deep detachment - 2nd puff also detachs the inner divtertor 2nd puff affects density - Ne0_TCI=4.2e20 at .91 s McPherson looking at Lyman_alpha and Li-like N. |
| Sep 1 1999 05:13:28:637PM | 990901022 | Jim Terry | Disrupts after the 1st N_2 puff McPherson looking at Lyman_alpha and Li-like N. |
| Physics Operator Comments | |||
| Sep 1 1999 08:05:26:920AM | Jim Irby | Did cold start Loaded shot 990826002 | |
| Sep 1 1999 08:26:23:297AM | Jim Irby | Raised flat-top density from 1e20 to 1.25e20 per JT request | |
| Sep 1 1999 08:45:23:310AM | Jim Irby | Removed -.0005 T tweak on Br_0 left from shot 990826002. There was no tweak on 990831028. | |
| Sep 1 1999 09:21:52:230AM | Jim Irby | Took flat-top request up to 1.35e20. Earlier value would have been a little low for peak density. | |
| Sep 1 1999 09:50:04:700AM | Jim Irby | Changed TF current from -144 to -150 kA. Extended flat-top to 1.5 seconds. | |
| Sep 1 1999 10:16:16:797AM | 990901001 | Jim Irby | Good shot Br0 -.001 at 5 ms BZ0 +.001 at 5 ms Peak density 2e20 early 2.5e20 late |
| Sep 1 1999 10:16:33:950AM | 990901002 | Jim Irby | Dropped density request back to 1.0e20. JT noticed we seem to have lost control of x-point at the higher density |
| Sep 1 1999 10:39:04:480AM | 990901003 | Jim Irby | Increased NL04 request to 1.5e20 Moved RXL in 5 mm Moved ZXL down 5 mm |
| Sep 1 1999 10:57:45:810AM | 990901003 | Jim Irby | Good shot Br0 -.001 T at 5 ms Bz0 +.0007 at 5 ms RF faulted |
| Sep 1 1999 11:10:48:170AM | 990901004 | Jim Irby | Bruce and Jim head into cell to made some diagnostic adjustments Decreased RCUR from 0.670 to 0.668 to increase outer gap by 4 mm Density request to 1.75e20 from 1.50e20 Good shot |
| Sep 1 1999 11:31:06:700AM | 990901005 | Jim Irby | Extended density rampdown from 1.0 to 1.4 seconds Moved RXL in another 5mm Good shot |
| Sep 1 1999 11:57:12:950AM | 990901006 | Jim Irby | Density request to 2.0e20 from 1.75e20 Plasma Lost it at 1.6 second EF1U maxed out Bz0 +.0005 at 5 ms Br0 -.0008 at 5 ms |
| Sep 1 1999 12:26:29:513PM | 990901007 | Jim Irby | Repeat Plasma Lost it at about 1.6 seconds again --- lots of gas Problems with CAMAC |
| Sep 1 1999 12:45:51:000PM | 990901008 | Jim Irby | Increased density request to 2.25e20 upto 1 second and then started rampdown RF off the air until the density is brought back down Plasma Lost it again at about 1.6 seconds Bz0 +.002 T again at 5 ms Br0 -.00067 T at 5 ms |
| Sep 1 1999 01:03:53:030PM | 990901009 | Jim Irby | Flappers open for full shot Otherwise it is a repeat Plasma Lost it at about 1.55 seconds More CAMAC problems --- most data recovered |
| Sep 1 1999 01:42:31:670PM | 990901010 | Jim Irby | Flaps closed for this shot Extended pre-puff 2 ms to help reduce early x-rays Plasma --- x-rays reduced but very different density Foil bolo indicates much more radiation Lost it at 1.39 seconds, almost full current distruption OH1 at 27 kA limit |
| Sep 1 1999 01:38:14:623PM | 990901011 | Jim Irby | Lower density request to 2.0e20 to reduce disruptivity Flaps stay closed Fizzle ---- Earl suggests making Br a little more negative ---- Steve suggests it's Bz |
| Sep 1 1999 02:01:58:047PM | 990901012 | Jim Irby | No changes basepressure before shot 8.5e-7 Torr Plasma Lost it at 1.2 seconds, most gatevalves closed Foil goes up to 2 MW briefly at 0.9 seconds. Density, Ha signals remain "noisy" to end of shot. Lots of carbon claimed by spectros |
| Sep 1 1999 02:12:28:357PM | 990901013 | Jim Irby | Repeating again, but without injection I hope Plasma Got to 1.53 seconds -- early injection |
| Sep 1 1999 02:25:07:857PM | 990901014 | Jim Irby | Dropped density request to 1.35e20 from 2.25e20 --- try to reproduce shot 1 Plasma Looks good --- nothing railed --- looks clean |
| Sep 1 1999 02:55:53:450PM | 990901015 | Jim Irby | Density request to 1.85e20 Plasma Looks good --- 1.69 seconds |
| Sep 1 1999 03:08:24:420PM | 990901016 | Jim Irby | No changes Plasma for 1.75 seconds --- flappers were open Bz0 +.0027 at 5 ms Br0 -.00055 at 5 ms |
| Sep 1 1999 03:21:55:653PM | 990901017 | Jim Irby | No changes again --- edge guys seem happy Base pressure before shot 1.3e-6 Torr Plasma --- 1.7 seconds |
| Sep 1 1999 03:57:46:857PM | 990901018 | Jim Irby | Enabled N2 puff on b_side_upper from 0.620 to 0.64 seconds --- 5.38 psi Plasma --- 1.72 seconds Bz0 +0.0021 Br0 -0.0006 |
| Sep 1 1999 04:16:24:653PM | 990901019 | Jim Irby | Edge guys go to CELL Extended N2 puff by 30 ms: 0.62 to 0.67 seconds: 5.38 psi Plasma --- 1.71 seconds --- No sign of N2 ---- switching to b_side_lower for N2 puff |
| Sep 1 1999 04:28:15:373PM | 990901020 | Jim Irby | Switched nitrogen puff from b_side_upper to b_side lower replacing the argon Puff from 0.62 to 0.67 ms at 5 psi base pressure 1.1e-6 Plasma --- 1.67 seconds --- N2 puff doubles 2Pi |
| Sep 1 1999 04:53:16:217PM | 990901021 | Jim Irby | Added two more puffs of N2 and extended first puff: 0.62 to 0.69 0.80 to 0.85 1.05 to 1.10 Plasma ---- 1.12 seconds --- Last puff did it in?? |
| Sep 1 1999 05:05:30:013PM | 990901022 | Jim Irby | Removed 3rd puff: 1st puff 0.62 to 0.71 2nd puff 0.80 to 0.83 Plasma --- but only to 0.73 seconds --- 1st puff?? |
| Engineering Operator Comments | ||||
| Shot | Time | Type | Status | Comment |
| 1 | 09:53:14:793AM | Plasma | Ok | no faults/plasma |
| 2 | 10:20:28:310AM | Plasma | Ok | no faults/plasma |
| 3 | 10:40:12:590AM | Plasma | Ok | no faults/plasma |
| 4 | 11:02:33:513AM | Plasma | Ok | no faults/plasma |
| 5 | 11:22:51:030AM | Plasma | Ok | no faults/plasma |
| 6 | 11:43:08:327AM | Plasma | Ok | no faults/plasma |
| 7 | 12:03:58:077PM | Plasma | Ok | (null) |
| 8 | 12:31:39:593PM | Plasma | Ok | (null) |
| 9 | 12:50:25:310PM | Plasma | Ok | (null) |
| 10 | 01:12:50:047PM | Plasma | Ok | (null) |
| 11 | 01:31:48:200PM | Plasma | Ok | no faults/fizzel |
| 12 | 01:44:29:483PM | Plasma | Ok | (null) |
| 13 | 02:01:13:013PM | Plasma | Ok | (null) |
| 14 | 02:19:52:890PM | Plasma | Ok | (null) |
| 15 | 02:39:25:700PM | Plasma | Ok | (null) |
| 16 | 02:58:33:480PM | Plasma | Ok | (null) |
| 17 | 03:16:51:153PM | Plasma | Ok | (null) |
| 18 | 03:35:55:233PM | Plasma | Ok | (null) |
| 19 | 04:01:14:170PM | Plasma | Ok | (null) |
| 20 | 04:22:46:937PM | Plasma | Ok | (null) |
| 21 | 04:43:39:030PM | Plasma | Ok | (null) |
| 22 | 04:58:15:967PM | Plasma | Ok | (null) |