| Miniproposals | ||||||||||
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| Operators | |
| Session leader(s): | Dmitri Mossessian |
| Physics operator(s): | Earl Marmar |
| Engineering operator(s): | Ed Fitzgerald,Bill Cochran |
| Engineering Operator Run Comment |
| MP #315 JET non-dimensional similarity. Mossessian/Marmar/Cochran/Fitzg |
| Session Leader Plans |
| Physics Operators Plans |
| Session Leader Summaries |
| Entered: Jul 7 2004 03:49:31:820PM |
| Author: To Be Determined |
| Run summary for 1021104 - JET dimensionless identity expt. (MP#315) Background: We have developed the shape that is close to the one that was run on JET - 1020904007. One of the problems was that we tried to go to lower than normal epsilon=0.3 and in the process lost control of elongation and upper delta. We will need to start from this shape and try to tweak it to match the JET shape. The shape changes somewhat in H-mode (higher beta pushes triangularity up) so we will have to compare H-mode plasmas. Shot 1020904007 is a 1 MA shot. JET was actually able to run lower current, so we will need to reprogram the current to something around 0.8 MA., Bt ~5.3 T. The exact value of current, as well as toroidal field, will depend on the minor radius we will get for our plasma. Once we obtain a satisfactory shape we will do density/power scan to cover the range of pedestal parameters that was accessed on JET. We will start with target nl=8e19, P_RF=2 MW. JET actually ran with lower triangularity of 0.35-0.4. On C-Mod we can get delta_lower=0.45 without problems, but lower values mean that we have to move outer strike point out of the divertor. We are not sure what will happen if we do that, but perhaps we could try. The 1021031 run showed that at lower triangularity plasma does not behave in a "usual way". Mainly, we could not get a good QC mode for current above 0.6 MA. So it may be important to get as good a delta match as possible with JET - we might even get the same kind of ugly H-mode that we saw on JET, with bursts of ELMs or something like ELMs between short ELM-free periods. Summary: Good match in Ip and Bt was obtained easily. Good shape match was achieved on shot 7. Interestingly, the value of upper triangularity from JET EFIT is larger than the corresponding value for C-Mod, but boundary plots, when overlayed, look very similar. So we assume that we got good shape match and proceeded with density and temperature scan to match pedestal parameters. It turns out that density scan is not really possible - RF refused to perform at higher target densities (nl>1e20). The temperature scan also was not very wide (again becase of troubles with RF and/or heating efficiency) but eventually we got something like a good match of pedestal Te and ne. The net result is good - we had matched shape and pedestals. Further conclusions will follw after data analysis. Good shots: 1021104006 Plasma with 4 ELM-free H-modes ___________________________________ 1021104007 move RXL out 5 mm; move RXU out 1 cm Plasma with long EDA-like H-mode with dithering bursts. The shape is pretty good ---------------------------------------------------------------------------- 1021104008 TF current to -152 kA after 0.1 s (from -150 kA) increase target nl04 to 1e20 from 0.8e20 Similar to 7. ---------------------------------------------------------------------------- 1021104017 nl04 target to 1.0e20 RF refused to work with 1.2e20 target. Returned to 1e20. H-mode . RF is tripping. Next shot - asking for 1.5 MW RF ---------------------------------------------------------------------------- 1021104018 h-mode starting at 1.0 s ---------------------------------------------------------------------------- 1021104020 1.8 MW RF, EDA-like H-mode with dithering bursts that cause RF to trip. Next shot - RF to 2.5 MW ---------------------------------------------------------------------------- 1021104021 2.5 MW RF and tripping. Similar to 20. Next - 3 MW RF ---------------------------------------------------------------------------- 1021104022 H-mode, RF trips a lot. Te pedestal changes from ~350 to 200 eV - not very different from lower power shots. ---------------------------------------------------------------------------- 1021104023 Similar to 22. Next shot - try target 1.2e20 again. ---------------------------------------------------------------------------- 1021104024 Target goes up to 1.1e20. Te pedestal is 400 eV briefly, ne_ped 2.7e20. - reasonable match Next - try higher density. ---------------------------------------------------------------------------- 1021104026 Target >1.1e20 does not work (no H-mode). Returned to 1.1e20. RF 2.5 MW and tripping. ---------------------------------------------------------------------------- 1021104029 Delta_lower=0.55. Similar to 28 ---------------------------------------------------------------------------- 1021104030 Same as 29. Next shot - decrease delta_lower to 0.35 ---------------------------------------------------------------------------- 1021104031 Very good shape match, but very ugly H-mode. |
| Physics Operator Summaries |
| Entered: Jul 7 2004 04:37:16:787PM |
| Author: To Be Determined |
| Physop run summary, 1021104 MP#315 JET non-dimensional similarity SL Mossessian PO Marmar ECDC at 2e-4 over the weekend with 60 degree bake, stopping by 8:00 am. Power systems as on 1021101002 Gas and gate-valve setup as on 1021101 ICRF: Transmitters 1, 2 and 3 in run-on by 8:00 am The run will start at 10:00 am, and may be extended to 6:00 pm if warranted. Plan: Start from a shot like 1020904007, but adjust to match JET parameters. Background: We have developed the shape that is close to the one that was run on JET - 1020904007. One of the problems was that we tried to go to lower than normal epsilon=0.3 and in the process lost control of elongation and upper delta. We will need to start from this shape and try to tweak it to match the JET shape (Dmitri has a code that compares boundaries for given shot/time). The shape changes somewhat in H-mode (higher beta pushes triangularity up) so we will have to compare H-mode plasmas. Shot 1020904007 is a 1 MA shot. JET was actually able to run lower current, so we will need to reprogram the current to something around 0.8 MA., Bt ~5.3 T. The exact value of current, as well as toroidal field, will depend on the minor radius we will get for our plasma. Once we obtain a satisfactory shape we will do density/power scan to cover the range of pedestal parameters that was accessed on JET. We will start with target nl=8e19, P_RF=2 MW. JET actually ran with lower triangularity of 0.35-0.4. On C-Mod we can get delta_lower=0.45 without problems, but lower values mean that we have to move outer strike point out of the divertor. We are not sure what will happen if we do that, but perhaps we could try. The 1021031 run showed that at lower triangularity plasma does not behave in a "usual way". Mainly, we could not get a good QC mode for current above 0.6 MA. So it may be important to get as good a delta match as possible with JET - we might even get the same kind of ugly H-mode that we saw on JET, with bursts of ELMs or something like ELMs between short ELM-free periods. Results: The run was moderately successful. We managed to get quite good matches to the JET shape. The RF was trippy, but there were a variety of H-modes produced at power levels between 1.5 and 3 MW, with some triangularity scans and limited density scans. I don't know if the H-modes were as "ugly" as on JET, but they were certainly not beautiful. The run went to 6:00 pm. Startup was balky early in the run, until the fill pressure was lowered to the 0.055 milli-Torr range for shot 16 (20 msec puff on PG4). After that we got 16 plasmas in a row. After a data acquisition glitch on shot 1, there were no power supply or computer problems today. Scorecard: Plasmas 23 Fizzles 7 Duds 1 Total cycles 31 From: SPANNA::MARMAR Date: 4-NOV-2002 18:39:46 Subj: Physop run summary 1021104 Physop run summary, 1021104 MP#315 JET non-dimensional similarity SL Mossessian PO Marmar ECDC at 2e-4 over the weekend with 60 degree bake, stopping by 8:00 am. Power systems as on 1021101002 Gas and gate-valve setup as on 1021101 ICRF: Transmitters 1, 2 and 3 in run-on by 8:00 am The run will start at 10:00 am, and may be extended to 6:00 pm if warranted. Plan: Start from a shot like 1020904007, but adjust to match JET parameters. Background: We have developed the shape that is close to the one that was run on JET - 1020904007. One of the problems was that we tried to go to lower than normal epsilon=0.3 and in the process lost control of elongation and upper delta. We will need to start from this shape and try to tweak it to match the JET shape (Dmitri has a code that compares boundaries for given shot/time). The shape changes somewhat in H-mode (higher beta pushes triangularity up) so we will have to compare H-mode plasmas. Shot 1020904007 is a 1 MA shot. JET was actually able to run lower current, so we will need to reprogram the current to something around 0.8 MA., Bt ~5.3 T. The exact value of current, as well as toroidal field, will depend on the minor radius we will get for our plasma. Once we obtain a satisfactory shape we will do density/power scan to cover the range of pedestal parameters that was accessed on JET. We will start with target nl=8e19, P_RF=2 MW. JET actually ran with lower triangularity of 0.35-0.4. On C-Mod we can get delta_lower=0.45 without problems, but lower values mean that we have to move outer strike point out of the divertor. We are not sure what will happen if we do that, but perhaps we could try. The 1021031 run showed that at lower triangularity plasma does not behave in a "usual way". Mainly, we could not get a good QC mode for current above 0.6 MA. So it may be important to get as good a delta match as possible with JET - we might even get the same kind of ugly H-mode that we saw on JET, with bursts of ELMs or something like ELMs between short ELM-free periods. Results: The run was moderately successful. We managed to get quite good matches to the JET shape. There were a variety of H-modes produced at RF power levels between 1.5 and 3 MW, with some triangularity scans and limited density scans. I don't know if the H-modes were as "ugly" as on JET, but they were certainly not beautiful. The run went to 6:00 pm. Startup was balky early in the run, until the fill pressure was lowered to the 0.055 milli-Torr range for shot 16 (20 msec puff on PG4). After that change we got 16 plasmas in a row. After a data acquisition glitch on shot 1, there were no other power supply or computer problems today. The TF resistance was reading a little high betwen shots; this slowed the shot cycle by about 2 or 3 minutes per shot. Scorecard: Plasmas 23 Fizzles 7 Duds 1 Total cycles 31 |
| Session Leader Comments | |||
| Nov 4 2002 11:09:36:710AM | Dmitri Mossessian | MP#315 JET non-dimensional similarity We have developed the shape that is close to the one that was run on JET - 1020904007. One of the problems was that we tried to go to lower than normal epsilon=0.3 and in the process lost control of elongation and upper delta. We will need to start from this shape and try to tweak it to match the JET shape (Dmitri has a code that compares boundaries for given shot/time). The shape changes somewhat in H-mode (higher beta pushes triangularity up) so we will have to compare H-mode plasmas. Shot 1020904007 is a 1 MA shot. JET was actually able to run lower current, so we will need to reprogram the current to something around 0.8 MA., Bt ~5.3 T. The exact value of current, as well as toroidal field, will depend on the minor radius we will get for our plasma. Once we obtain a satisfactory shape we will do density/power scan to cover the range of pedestal parameters that was accessed on JET. We will start with target nl=8e19, P_RF=2 MW. JET actually ran with lower triangularity of 0.35-0.4. On C-Mod we can get delta_lower=0.45 without problems, but lower values mean that we have to move outer strike point out of the divertor. We are not sure what will happen if we do that, but perhaps we could try. The 1021031 run showed that at lower triangularity plasma does not behave in a "usual way". Mainly, we could not get a good QC mode for current above 0.6 MA. So it may be important to get as good a delta match as possible with JET - we might even get the same kind of ugly H-mode that we saw on JET, with bursts of ELMs or something like ELMs between short ELM-free periods. | |
| Nov 4 2002 11:10:40:177AM | 1021104003 | Dmitri Mossessian | Strat from 1020904007, reduce Ip to 0.8MA Lower delta too high, upper delta too low. No edge Thomson - alignment problem |
| Nov 4 2002 11:12:17:650AM | 1021104004 | Dmitri Mossessian | Moving RXL out to reduce delta caused disruption. Just before the disruption the shape match was good. |
| Nov 4 2002 12:10:50:363PM | 1021104006 | Dmitri Mossessian | Plasma with 4 ELM-free H-modes |
| Nov 4 2002 12:12:29:023PM | 1021104007 | Dmitri Mossessian | Plasma with long EDA-like H-mode with dithering bursts. Next shot - target to 1e20 |
| Dec 9 2002 01:52:39:837PM | 1021104008 | Dmitri Mossessian | Similar to 7. Next shot - target 1.2e20 |
| Nov 4 2002 02:33:19:803PM | 1021104017 | Dmitri Mossessian | RF refused to work with 1.2e20 target. Returned to 1e20. H-mode . RF is tripping. Next shot - asking for 1.5 MW RF |
| Nov 4 2002 03:13:18:143PM | 1021104020 | Dmitri Mossessian | 1.8 MW RF, EDA-like H-mode with dithering bursts that cause RF to trip. Next shot - RF to 2.5 MW |
| Nov 4 2002 04:02:04:367PM | 1021104021 | Dmitri Mossessian | 2.5 MW RF and tripping. Similar to 20. Next - 3 MW RF |
| Nov 4 2002 04:03:34:523PM | 1021104022 | Dmitri Mossessian | H-mode, RF trips a lot. Te pedestal changes from ~350 to 200 eV - not very different from lower power shots. Next shot - repeat. |
| Nov 4 2002 04:03:56:837PM | 1021104023 | Dmitri Mossessian | Similar to 22. Next shot - try target 1.2e20 again. |
| Nov 4 2002 05:15:03:023PM | 1021104024 | Dmitri Mossessian | Target goes up to 1.1e20. Te pedestal is 400 eV briefly, ne_ped 2.7e20. - reasonable match Next - try higher density. |
| Nov 4 2002 05:15:50:290PM | 1021104026 | Dmitri Mossessian | Target >1.1e20 does not work (no H-mode). Returned to 1.1e20. RF 2.5 MW and tripping. |
| Nov 4 2002 05:47:35:950PM | 1021104029 | Dmitri Mossessian | Delta_lower=0.55. Similar to 28 |
| Nov 4 2002 05:48:29:497PM | 1021104030 | Dmitri Mossessian | Same as 29. Next shot - decrease delta_lower to 0.35 |
| Nov 4 2002 06:09:31:907PM | 1021104031 | Dmitri Mossessian | Very good shape match, but very ugly H-mode. |
| Physics Operator Comments | |||
| Nov 4 2002 10:04:12:420AM | 1021104001 | Earl Marmar | load segment 1 from 1021031004, add 1 msec to prefill puff load segment 2 from 1020904007; reduce nl04 to 8e19, reduce Ip to .8 MA fizzle; very slow current rise |
| Nov 4 2002 10:22:55:340AM | 1021104002 | Earl Marmar | reduce prefill 3 ms dud; fields look ok |
| Nov 4 2002 10:51:23:320AM | 1021104003 | Earl Marmar | increase prepuff 6 msec (now 28 msec) plasma 1.5 MW RF; semi-EDA |
| Nov 4 2002 11:05:07:687AM | 1021104004 | Earl Marmar | move RXU in 2 cm, RXL out 1 cm plasma disrupt at .61 s (strike too high on nose?); n/ncrit goes up to 1.3 |
| Nov 4 2002 11:11:39:070AM | 1021104005 | Earl Marmar | reduce prefill by 1 msec move RXL back in 1 cm fizzle |
| Nov 4 2002 11:31:52:180AM | 1021104006 | Earl Marmar | no PCS changes plasma |
| Nov 4 2002 11:47:05:017AM | 1021104007 | Earl Marmar | move RXL out 5 mm; move RXU out 1 cm plasma Dmitri says the shape is pretty good |
| Nov 4 2002 12:10:13:460PM | 1021104008 | Earl Marmar | TF current to -152 kA after 0.1 s (from -150 kA) increase target nl04 to 1e20 from 0.8e20 plasma |
| Nov 4 2002 12:21:14:177PM | 1021104009 | Earl Marmar | raise nl04 target to 1.2e20 from 1.0e20 tweak upper x-point (out 3 mm, up 3 mm) fizzle |
| Nov 4 2002 12:46:39:983PM | 1021104010 | Earl Marmar | no pcs changes plasma no H-mode |
| Nov 4 2002 12:48:50:237PM | 1021104011 | Earl Marmar | lowered pg4 prepuff by 2 msec fizzle |
| Nov 4 2002 01:05:52:683PM | 1021104012 | Earl Marmar | raise pg4 prepuff by 2 msec fizzle |
| Nov 4 2002 01:22:14:460PM | 1021104013 | Earl Marmar | load segment 1 from 1021030013 plasma no H-mode |
| Nov 4 2002 01:36:26:810PM | 1021104014 | Earl Marmar | no pcs changes fizzle |
| Nov 4 2002 01:54:32:850PM | 1021104015 | Earl Marmar | increase pg4 prepuff to 27 msec fizzle |
| Nov 4 2002 02:07:14:370PM | 1021104016 | Earl Marmar | reduce pg4 prefill to 20 msec plasma no h-mode |
| Nov 4 2002 02:33:01:490PM | 1021104017 | Earl Marmar | nl04 target to 1.0e20 plasma H-mode |
| Nov 4 2002 02:39:00:513PM | 1021104018 | Earl Marmar | no pcs changes plasma h-mode starting at 1.0 s |
| Nov 4 2002 03:00:17:687PM | 1021104019 | Earl Marmar | no pcs changes plasma no H-Mode |
| Nov 4 2002 03:22:03:877PM | 1021104020 | Earl Marmar | no pcs changes plasma H-Mode |
| Nov 4 2002 03:42:28:023PM | 1021104021 | Earl Marmar | no PCS changes plasma H-mode |
| Nov 4 2002 03:44:07:637PM | 1021104022 | Earl Marmar | no PCS changes plasma multiple H-modes |
| Nov 4 2002 04:04:12:447PM | 1021104023 | Earl Marmar | TF ramp-down started 200 ms earlier (now at 1.3 seconds) plasma multiple H-modes |
| Nov 4 2002 04:18:06:890PM | 1021104024 | Earl Marmar | nl04 target to 1.2e20 BT rampdown start at 1.1 plasma H-Mode |
| Nov 4 2002 04:36:36:997PM | 1021104025 | Earl Marmar | nl04 target to 1.32e20 adjust TF rampdown (try to avoid disruption at 350 kA) plasma no H-mode |
| Nov 4 2002 04:50:07:110PM | 1021104026 | Earl Marmar | nl04 target back to 1.2e20 plasma H-Mode |
| Nov 4 2002 05:05:20:587PM | 1021104027 | Earl Marmar | no pcs changes plasma no H-Mode |
| Nov 4 2002 05:19:52:500PM | 1021104028 | Earl Marmar | decrease RXL by 1 cm (increase delta_lower) plasma H-Mode |
| Nov 4 2002 06:06:58:980PM | 1021104029 | Earl Marmar | decrease RXL another 1 cm plasma H-Mode |
| Nov 4 2002 06:07:20:730PM | 1021104030 | Earl Marmar | no PCS changes plasma H-Mode |
| Nov 4 2002 06:08:15:293PM | 1021104031 | Earl Marmar | move RXL out 2.5 cm (reduce delta_lower) plasma Short H-Mode |
| Engineering Operator Comments | ||||
| Shot | Time | Type | Status | Comment |
| 1 | 09:57:44:550AM | Plasma | Ok | |
| 2 | 10:19:19:943AM | Plasma | Ok | |
| 3 | 10:32:53:857AM | Plasma | Ok | |
| 4 | 10:52:16:087AM | Plasma | Ok | |
| 5 | 11:07:17:220AM | Plasma | Ok | |
| 6 | 11:20:30:943AM | Plasma | Ok | |
| 7 | 11:34:38:887AM | Plasma | Ok | |
| 8 | 11:54:21:183AM | Plasma | Ok | |
| 9 | 12:10:47:380PM | Plasma | Ok | |
| 10 | 12:30:13:503PM | Plasma | Ok | |
| 11 | 12:45:41:543PM | Plasma | Ok | |
| 12 | 01:00:35:067PM | Plasma | Ok | |
| 13 | 01:15:40:103PM | Plasma | Ok | |
| 14 | 01:31:00:957PM | Plasma | Ok | |
| 15 | 01:46:57:887PM | Plasma | Ok | |
| 16 | 02:03:04:223PM | Plasma | Ok | |
| 17 | 02:18:40:047PM | Plasma | Ok | |
| 18 | 02:33:40:787PM | Plasma | Ok | |
| 19 | 02:50:23:157PM | Plasma | Ok | |
| 20 | 03:07:01:557PM | Plasma | Ok | |
| 21 | 03:22:52:597PM | Plasma | Ok | |
| 22 | 03:39:54:130PM | Plasma | Ok | |
| 23 | 03:56:31:030PM | Plasma | Ok | |
| 24 | 04:12:03:070PM | Plasma | Ok | |
| 25 | 04:26:39:717PM | Plasma | Ok | |
| 26 | 04:42:20:397PM | Plasma | Ok | |
| 27 | 04:57:55:107PM | Plasma | Ok | |
| 28 | 05:13:41:117PM | Plasma | Ok | |
| 29 | 05:28:34:907PM | Plasma | Ok | |
| 30 | 05:44:23:257PM | Plasma | Ok | |
| 31 | 05:58:23:327PM | Plasma | Ok | |