| Miniproposals | ||||||||||
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| Operators | |
| Session leader(s): | Rejean Boivin |
| Physics operator(s): | Steve Wolfe |
| Engineering operator(s): | Bill Cochran |
| Engineering Operator Run Comment |
| MP #142 AT preparation and H-mode density limit.Wolfe,Boivin,Cochran. |
| Session Leader Plans |
| Physics Operators Plans |
| Session Leader Summaries |
| Entered: Jul 7 2004 03:49:24:133PM |
| Author: To Be Determined |
June 13th 2000 SL R. Boivin PO S. Wolfe EO B. Cochran AT discharge preparation Low density H-modes MP 142 Run Plan: -------- In preparation for the AT experiments on C-Mod, we will need to be able to run at lower density. However, the presence of H-mode with Lower Hybrid may complicate matters seriously. We will try to understand and document the H-mode low density limit, and project this case to AT discharges. Naturally this should also help us in understanding the implications/effects of neutrals at low density. -1) ECDC in helium to unload walls, overnight preferably 2 hours minimum. => We got a total of 12.5 hours of ECDC in helium at 5e-5 pressure. 0) Start with OH test and 50KA TF test 1) Establish standard 1MA, slightly lower field 5.1T discharge, but start with central nl of 6.0x10^19. Look for H-mode power threshold - Ramp RF power with first D and E from 0.2MW to max power (total), starting at 0.5 sec, - If needed, consider adding J port power from 0.2MW (or thereabout) to maximum useful power. (later in the shot, say after 1 sec), - Include appropriate sharp drops in RF power to monitor absorption fraction. - monitor H/D ratio for optimal fraction (approx 5% and should remain the same throughout the day) - will probably require a few shots to get tune right - tweak outer gap as needed 2) Change density, by first going down in density to minimum reasonable w/o run-aways, and past the density limit with the available power. 3) If time seems available, and at density of 5x10^19 or so, change dynamically inner gap, with fixed RF power just below the previously obtained power threshold, to see if we can trigger the H-mode with increasing inner wall recycling. Repeat, also with no change in inner gap, for long RF pulse and document performance/conditions which should be similar to AT conditions (in L-mode). Diagnostics, - both Lya systems - FSP and ASP for SOL profiles (if possible). => ASP is not ready - McP if available to look at Lya, inner wall => McP stillh as problems but JT will manually put it there. - all Da, and related, inner wall as much as possible - ECE, GPC, VB, Thomson, all edge diag as possible. - helium puffing (Kaiser ok) - bolos as usual 4) We would like to consider having nitrogen available through NINJA to puff small amounts at the inner wall for diagnostic purposes late in the shot. Use only if they do not disturb anything else. (Mostly for the new Lya view at the inner wall). Overall, the machine and plasmas performed in the most bizarre way. The low density limit was indeed at very low density today for unknown reasons. We started with nl_04 at 6x10^19 and obtained H-mode at 0.7-0.8 MW (of RF), although later in the shot we got an ohmic H-mode. As we lowered the density, the threshold went down as expected (nl_04 ~ 5x10^19), and then up at 4x10^19 (1.3-1.4 MW) but still within available power. At those densities the H-modes were brief, and barely visible, but edge temperatures together with a good look at Dalpha were good indicators of H-modes. It was very clear that the H-modes were not being fuelled efficiently if at all and the H-modes died early. We definitely need neutrals to build the density pedestal, but not the temperature one. Attempts to go lower in density to get past the density limit pushed us to very low density nl_04~2x10^19 which is virtually our record for deliberate low density discharges. At those densities, we very quickly turned into that weird mode, where the sawteeth stabilized, Zeff went up, but radiation stayed low (or decrease a bit), and density went further down, actually turning on the gas feeback! Divertor was very hot, and scrape-off layer too. That was not a pleasant regime to be in, and all of them ended with disruptions, even with ohmic only. We stayed away from these conditions by going back up in density only. So we have a few shots to look at for h-mode fuelling at low density. The rest remains a mystery. |
| Physics Operator Summaries |
| Entered: Jul 7 2004 04:37:11:350PM |
| Author: To Be Determined |
| Physics Operator's Summary for June 13, 2000 MP#142 AT preparation and H-mode low-density limit SL: Boivin PO: wolfe EO: Cochran Engineering setup: ------------------ Overnight ECDC in HELIUM, stopping 2 hours before run. Run begins at 9:00 and ends at 17:00. Power system setup as on 1000602016 Gas setup - fill B-top with 6 psi of D2 Hybrid enabled fill B-side lower with 1 psi of Ar Hybrid DISABLED leave B-side upper as is Hybrid DISABLED fill C-side with 30 psi of D2 Hybrid enabled leave J-bottom as is Hybrid DISABLED Gas System: The following gas bottles should be added in preparation for possible use later during this run: H2, N2; these can replace the Krypton and Ethylene bottles presently on the system. The following gate valves should be enabled, assuming no vacuum problems: ECE, VUV DNB gate valve should be DISABLED at the start of the run. Run Plan: -------- In preparation for the AT experiments on C-Mod, we will need to be able to run at lower density. However, the presence of H-mode with Lower Hybrid may complicate matters seriously. We will try to understand and document the H-mode low density limit, and project this case to AT discharges. Naturally this should also help us in understanding the implications/effects of neutrals at low density. -1) ECDC in helium to unload walls, overnight preferably 2 hours minimum. 0) Any early morning engineering test. 1) Establish standard 1MA, slightly lower field 5.1T discharge, but start with central nl of 6.0x10^19. Look for H-mode power threshold - Ramp RF power with first D and E from 0.2MW to max power (total), starting at 0.5 sec, - If needed, consider adding J port power from 0.2MW (or thereabout) to maximum useful power. (later in the shot, say after 1 sec), - Include appropriate sharp drops in RF power to monitor absorption fraction. - monitor H/D ratio for optimal fraction (approx 5% ans should remain the same throughout the day) - will probably require a few shots to get tune right - tweak outer gap as needed 2) Change density, by first going down in density to minimum reasonable w/o run-aways, and past the density limit with the available power. 3) If time seems available, and at density of 5x10^19 or so, change dynamically inner gap, with fixed RF power just below the previously obtained power threshold, to see if we can trigger the H-mode with increasing inner wall recycling. Repeat, also with no change in inner gap, for long RF pulse and document performance/conditions which should be similar to AT conditions. Diagnostics, - both Lya systems - FSP and ASP for SOL profiles (if possible). - McP if available to look at Lya, inner wall - all Da, and related, inner wall as much as possible - ECE, GPC, VB, Thomson, all edge diag as possible. - helium puffing (Kaiser ok) - bolos as usual 4) I would like to consider having nitrogen available through NINJA to puff small amounts at the inner wall for diagnostic purposes late in the shot. Use only if they do not disturb anything else. (Mostly for the new Lya view at the inner wall). Shot set up: ------------- Loaded from 1000602016, a 1.06MA, 7e19, 5.4T shot, and adjusted current to 1MA, nl4 to 6e19, tf current to -142000 (5.1T). Since DNB not active, set pg4 pre-puff to 24msec. Set up clearin wire (no gain) in segment #1, and put offset=12700, re-drew waveform so that new=old + 12700/|ip|, to prepare for implementing change recommended in physop summary of 1000525. Note that this waveform is close to what we actually want, and what Ian's predictor signals say we got on 1000602016. Results: -------- The run got off to a pretty good start. At 0.6e20, got good h-mode threshold point. The CLEARIN offset of 12700 was successfully implemented at shot#4. It seems to work as it should. I recommend these settings be adopted for future runs. On Shots 6-8 we dropped the density in steps of 1e19 down to 3e19. Basically, the density behaved as programmed, and we got past the minimum in threshold, but got h-modes at all densities. These h-modes appeared to have ELM activity, possibly type I. All these plasmas ramped down to essentially zero current, despite some thrashes in rampdown when the ef2's went to zero. Most had ohmic H-modes after the end of the RF pulse. On shot 9 we went to 2e19, and got a disruption at 1.1sec. The rest of the run was downhill. For the rest of the run we were plagued by disruptions, which seem to be related to a low-density behavior in which we lose the sawteeth and begin to get mhd activity which strongly reduces confinement, and eventually leads to a disruption. Moly levels were very high at the low densities. Zeff was also high, probably Mo dominated. Surprisingly, Prad was not excessive. We finally got an inner gap scan, as called for in step (3) of the plan, at 4e19 on shot 24, but the mhd problem set in at .87sec or so, so the results are not conclusive. The RF performed well, but we saw very hot spots and injections from the E-port antenna. Some places glowed after the disruptions for over 100msec. J-port antenna was fired into post-plasma period with field and gas present, during the first part of the run. Light was seen on the j-port camera, indicating there is a breakdown of some sort happening at J. Later in the run, jport antenna was added at the end of the RF ramp, and it seemed to have a deleterious effect (see shot 16, for example.) Detailed shot summary: ------------------------ Started with oh and 50kA tf tests (#1,2) Shot 3 ran as programmed, got H-modes at <1MW, nl4 6e19. shot#4 changed clearin to use 12700 offset, new waveform. It works! some thrashing in rampdown, but ramps down to nearly 0 current. shot 5: adjust RCUR to reduce outer gap. shot 6: nl4 -> 5.e19; h-modes, threshold is lower shot 7: nl4 -> 4.e19; h-modes shot 8: nl4 -> 3.e19; h-modes, threshold going up shot 9: nl4 -> 2.e19; dithers, no h-mode. Disrupts early. shots 10-16: disruption recovery, ending with a successful shot back at 6e19; similar to #5. Run J-port late in shot, it cools! shot 17: Back to 2e19, similar to #9. No h-mode up to 2MW, lose sawteeth, disrupts at .97sec shot 18: try constant rf=2.2MW at 2e19; disrupts earlier shot 19: try 3.5e19; fizzle shot 20: try again, disrupts. shot 21: back to 6e19, fizzles. shot 22: runs to rampdown, starts an h-mode but it dies early shots 23-24: 4e19, inner gap ramp. #24 makes it through the ramp, dithering until loss of sawteeth. Scorecard: ----------- tests 2 duds 0 fizzles 4 plasmas 18 ------- -- shots 24 |
| Session Leader Comments | |||
| Jun 13 2000 09:01:05:890AM | Rejean Boivin | We need to make a test of the J antenna with "gas" and TF but no plasma, so we plan to do it at the end of the plasma. However, (I guess that makes it the first AT prep result!) is that we cannot run D and E early (0.5 sec) and J at 2.1 sec, the digitizer won't take data that long. Problem arises from the antenna crate in the cell. | |
| Jun 13 2000 09:01:26:513AM | Rejean Boivin | AT discharge preparation Low density H-modes Run Plan: -------- In preparation for the AT experiments on C-Mod, we will need to be able to run at lower density. However, the presence of H-mode with Lower Hybrid may complicate matters seriously. We will try to understand and document the H-mode low density limit, and project this case to AT discharges. Naturally this should also help us in understanding the implications/effects of neutrals at low density. -1) ECDC in helium to unload walls, overnight preferably 2 hours minimum. => We got a total of 12.5 hours of ECDC in helium at 5e-5 pressure. 0) Start with OH test and 50KA TF test 1) Establish standard 1MA, slightly lower field 5.1T discharge, but start with central nl of 6.0x10^19. Look for H-mode power threshold - Ramp RF power with first D and E from 0.2MW to max power (total), starting at 0.5 sec, - If needed, consider adding J port power from 0.2MW (or thereabout) to maximum useful power. (later in the shot, say after 1 sec), - Include appropriate sharp drops in RF power to monitor absorption fraction. - monitor H/D ratio for optimal fraction (approx 5% and should remain the same throughout the day) - will probably require a few shots to get tune right - tweak outer gap as needed 2) Change density, by first going down in density to minimum reasonable w/o run-aways, and past the density limit with the available power. 3) If time seems available, and at density of 5x10^19 or so, change dynamically inner gap, with fixed RF power just below the previously obtained power threshold, to see if we can trigger the H-mode with increasing inner wall recycling. Repeat, also with no change in inner gap, for long RF pulse and document performance/conditions which should be similar to AT conditions (in L-mode). Diagnostics, - both Lya systems - FSP and ASP for SOL profiles (if possible). => ASP is not ready - McP if available to look at Lya, inner wall => McP stillh as problems but JT will manually put it there. - all Da, and related, inner wall as much as possible - ECE, GPC, VB, Thomson, all edge diag as possible. - helium puffing (Kaiser ok) - bolos as usual 4) We would like to consider having nitrogen available through NINJA to puff small amounts at the inner wall for diagnostic purposes late in the shot. Use only if they do not disturb anything else. (Mostly for the new Lya view at the inner wall). | |
| Jun 13 2000 10:26:03:047AM | 1000613003 | Rejean Boivin | Shot 003 First plasma attempt: Plasma! RF up to 1.5 MW or so, retune for next shot Went to H-mode at P~1 MW Some magnetics problems, watch out for EFIT. It appears that we have some lone ELMs. |
| Jun 13 2000 10:40:41:670AM | 1000613004 | Rejean Boivin | Shot 004 Plasma Rf better pulse, but gap is large, up 1.7 cm Went to H-mode at P~0.7 MW, less than previous one for same density Reduce gap for next shot. |
| Jun 13 2000 02:14:25:497PM | 1000613006 | Rejean Boivin | Shot 006 Plasma Lower density nl_04 ~ 5.0x10^19 Went to H-mode at P~0.7 MW Also Ohmic H-mode at the end of the shot. Next shot: Reduce density to nl_04 of 4x10^19 |
| Jun 13 2000 02:14:10:403PM | 1000613007 | Rejean Boivin | Shot 007 Plasma Lower density nl_04 ~ 4.0x10^19 Went to H-mode at P~1.4 MW Appears we passed the upturn in P_thresh Also Ohmic H-mode at the end of the shot. Next shot: Reduce density to nl_04 of 3x10^19 |
| Jun 13 2000 02:13:57:170PM | 1000613008 | Rejean Boivin | Shot 008 Plasma Lower density nl_04 ~ 3.5x10^19 Went to H-mode at P~1.4 MW Still make it to H-mode with little difficulty. Next shot: Reduce density to nl_04 of 2x10^19 |
| Jun 13 2000 02:13:38:797PM | 1000613009 | Rejean Boivin | Shot 009 Plasma Lower density nl_04 ~ 3x10^19 Edge temperature and Ha show signs of H-mode but no density rise. Lack of fueling for the density pedestal? Brick came in and killed. Next shot: Repeat |
| Jun 13 2000 12:27:28:670PM | 1000613010 | Rejean Boivin | Shot 010 Fizzle, not surprising after such a disruption. |
| Jun 13 2000 12:59:46:560PM | 1000613011 | Rejean Boivin | Shot 011 Short plasma nl_04 ~ 2x10^19 signs of runaways, from neuts only disrupted early, during flat top. |
| Jun 13 2000 01:16:45:687PM | 1000613012 | Rejean Boivin | Shot 012 Short plasma, disrupts near 0.8 sec nl_04 ~ 3x10^19 density and temperature dropping after 0.7 sec but no increase in radiation. Lose the plasma not too long after that. |
| Jun 13 2000 01:27:05:217PM | 1000613013 | Rejean Boivin | Shot 013 Fizzle no RF for next shot. |
| Jun 13 2000 02:15:28:357PM | 1000613014 | Rejean Boivin | Shot 014 plasma, disrupted shortly after 1 sec. no RF, confinement goes way down just before disruption, MHD? go higher in density for next shot |
| Jun 13 2000 02:16:24:797PM | 1000613015 | Rejean Boivin | Shot 015 plasma, disrupted shortly after 1.5 sec. no RF, higher density nl_04 near 6x10^19 next shot reenable RF |
| Jun 13 2000 02:32:11:437PM | 1000613016 | Rejean Boivin | Shot 016 plasma, multiple H-modes a la Bart! higher density nl_04 near 6x10^19 next shot go back down to 2-3 x 10^19 try to repeat shot 009 |
| Jun 13 2000 04:08:48:890PM | 1000613017 | Rejean Boivin | Shot 017 plasma, no H-modes, disrupted around 1.0 sec density nl_04 =2.0x10^19 next shot RF squared at 2.0 MW... |
| Jun 13 2000 03:21:52:890PM | 1000613018 | Rejean Boivin | Shot 018 plasma, no H-modes, disrupted around 0.75 sec density nl_04 =2.0x10^19 RF squared at 2.0 MW no H-mode, but sawtooth goes away again at 0.5 sec (this time). |
| Jun 13 2000 03:59:10:043PM | 1000613020 | Rejean Boivin | Shot 020 plasma, no H-modes, disrupted around 0.90 sec density nl_04 =3.5x10^19 but then dropping again, in spite of gas puffing RF squared at 2.0 MW no H-mode, but sawtooth goes away again at 0.7 sec (this time). |
| Jun 13 2000 04:27:35:093PM | 1000613022 | Rejean Boivin | Shot 022 plasma, first a few H-modes, but then the density dropped and we stayed in L mode! density nl_04 =6x10^19 but then dropping again, in spite of gas puffing RF squared at 2.0 MW next shot, drop density to 4x10^19, and scan innner gap from 1.5 cm to zero |
| Jun 13 2000 04:51:50:873PM | 1000613023 | Rejean Boivin | Shot 023 plasma, 2 small H-modes, and tehn disrupted after that, something came in. density nl_04 =4x10^19 the H-modes were very slow in fuelling. RF squared at 2.0 MW next shot, repeat |
| Jun 13 2000 05:10:28:250PM | 1000613024 | Rejean Boivin | Shot 024 plasma, many small H-modes at first, and then went back into sawteeth stabilized followed by minor disruptions. the H-modes were very slow in fuelling. RF squared at 2.0 MW Inner gap was scanned dynamically during the shot. (the outer changed a bit oo). |
| Jun 13 2000 05:13:57:153PM | 1000613024 | Rejean Boivin | Brief summary The low density H-mode was extremely low, in fact lower than realized before. Threshold went up with lower density somewhat, in fact we obtained ohmic H-modes. In order to get to L-mode only, we got into that very low density regime where the plasma would stabilize sawteeth, density would drop, and gas puff would turn on even at nl_04 of 2x10^19. Confinement was then poor and disruptions followed. See run summary for more details. |
| Physics Operator Comments | |||
| Jun 12 2000 03:20:41:687PM | Steve Wolfe | Setting up for the low density H-mode run 1000613 Import seg 2 from 1000602016 change segment title ip from 1.06e6 -> 1.0e6 nl04 from 0.7e20->0.6e20 tf to -141000, rampdown to zero at 2.5sec pg3 maint level to 21V Argon pulse to 25msec Segment 1: pg4 to 25ms (DNB will be off) Load/clean and save as pcs$wolfe /shot=10006130000 Noticed that the TREE file was 230/2538 blocks. Josh truncated this. Re-save in pcs$wolfe. The large tree files have been there since May! Josh will look at truncating them to save some disk space. | |
| Jun 13 2000 07:46:59:670AM | Steve Wolfe | Change tf current from -141000 to -142000, slow rampdown shorten pre-puff to 24 msec. Put clearin on wire 4 in seg 1, gains off, offset=12700. load/clean Do a coldstart. Failed - a matrix not responding. Do a ccl remcam and try again. OK that worked. I had done a ccl remcam on spanna yesterday, so I don't understand why it needed it again, but it seems ok now. hloader log also ok. | |
| Jun 13 2000 08:15:09:217AM | Steve Wolfe | Draw a modified clearin waveform in seg 1, just for practice. Added 12700/|ip| to old waveform. | |
| Jun 13 2000 11:58:10:467AM | 1000613001 | Steve Wolfe | shot#1 : OH Tuesday test currents look ok. oh1: 0.6758 uohm oh2u: 0.2450 uohm oh2l: 0.3798 uohm got a gas puff at 1sec, with no valves enabled. clearin in sg 1 starts at zero, looks ok. proably the NINJA He puff. It got to 1.5e-5 gauge. |
| Jun 13 2000 11:58:26:640AM | 1000613002 | Steve Wolfe | shot#2: tf test. NINJA disabled, no gas this time. It looked like 28 peak went up on #1, but not nearly as much as the pressure rise. magnetics camac errors reading bp17 and 18jk, and others Rick to cell to work on TCI. CLEARIN in seg#1 has initial offset of 1825, up to 3000 during tf; at seg switch, jumps to -8450. Note that there is a program of -.03, and Ip has 25000a offset, so the start value may be ok. |
| Jun 13 2000 11:59:44:343AM | 1000613002 | Steve Wolfe | shot#2: tf test. NINJA disabled, no gas this time. It looked like 28 peak went up on #1, but not nearly as much as the pressure rise. |
| Jun 13 2000 11:58:43:170AM | 1000613003 | Steve Wolfe | shot#3: Try for plasma, using original CLEARIN programing This is a try at 6e19, 1MA, 5.1T. heaters went down before this shot, vessel temp to 6.0 degrees C/ plasma, several h-modes. More magnetics errors. startup is terrible, ip turns around. Current rise is too fast, bz too low. outer gap looks large, but it is probably missing data. I want to go ahead and implement the clearin offset change. |
| Jun 13 2000 11:59:07:217AM | 1000613004 | Steve Wolfe | shot#4: increase pg4 puff to 26msec change segment 2 clearin offset to 12700, copy waveform from seg1, smooth it out some. Ian's flux routines didn't run because of the magnetics errors, so I'm flying blind. It looked ok on shot 1. load it and hope. plasma, some vertical problems in rampdown, but clearin change seems to have worked. ramps ALL the way down. h-modes. startup still ratty. Gaps look about the same, outer gap around 1.8cm Rejean requests outer gap to go closer to 1.0. next shot: rcur from .665 to .668 ramp current down faster, end at 1.84 IC_ef4 from -1290 to -1280 |
| Jun 13 2000 11:59:21:547AM | 1000613005 | Steve Wolfe | shot#5: rcur from .665 to .668 to reduce outer gap. ramp current down faster, end at 1.84 pull clearin in more at rampdown IC_ef4 from -1290 to -1280 plasma, still vertical problem in rampdown, but runs full length. problem happens when ef2U zeros. breakdown is a little late, but no hesitation and fast current rise. oh2l resistance is up to .85uohm. ?? next shot: extend ef2byef4, and ic_ef4 longer in rampdown. lower density to 5e19. |
| Jun 13 2000 12:00:37:480PM | 1000613007 | Steve Wolfe | shot#7: nl4 to 4e19, maint level to 0.0 after .5sec clearin moved more negtive in rampdown. plasma, h-modes, at .78 sec this time, got the 4e19 ok. next shot: drop to 3e19 |
| Jun 13 2000 12:00:24:903PM | 1000613008 | Steve Wolfe | shot#8: nl4 to 3e19 plasma, h-modes around .8sec, nl=3.6e19 next shot: down to 2e19 |
| Jun 13 2000 12:16:16:123PM | 1000613009 | Steve Wolfe | shot#9: nl4 down to 2e19 disruption at 1.1sec Is it a brick? plasma is cooling long before the disruption dithers from .8sec, then cools. next shot, try a repeat. |
| Jun 13 2000 12:31:39:903PM | 1000613010 | Steve Wolfe | shot#10: repeat with nl4 down to 2e19 fizzle. slow current rise. CII up to .004 just go again |
| Jun 13 2000 12:50:39:140PM | 1000613011 | Steve Wolfe | shot#11: repeat with nl4 down to 2e19 early disruption, .66sec. runaways. better early current rise, still somewhat slow we did get 2e19. next shot, back to 3e19. |
| Jun 13 2000 01:15:44:797PM | 1000613012 | Steve Wolfe | shot#12: back to 3e19. disrupts at .8sec. no runaways. long hesitation, barely makes it. next shot, back to 4e19 |
| Jun 13 2000 02:14:06:450PM | 1000613013 | Steve Wolfe | shot#13: back to 4e19 fizzle. early bd, hesitates like on 12, doesn't make it this time. next shot, turn RF off for a shot, try to get through one. |
| Jun 13 2000 01:48:01:513PM | 1000613014 | Steve Wolfe | shot#14: back to 4e19, no RF. disrupts at 1.07sec, can't blame this on on RF injections. density right at 4e19, lose the sawteeth at ~.82, density drops a little, then disrupts later. Nothing obvious on MHD or bolo, but Raise density some more. |
| Jun 13 2000 02:07:00:873PM | 1000613015 | Steve Wolfe | shot#15: back to 6e19, maint pg3 to 15V, no RF. lower pre-puff to 24msec disrupts in rampdown, at 1.56sec. slow current rise, but makes it through. TRAQ2 data corrupted, have to run EFIT with PCS data. |
| Jun 13 2000 02:20:16:123PM | 1000613016 | Steve Wolfe | shot#16: turn rf back on. leave nl4 at 6e19. plasma, h-modes, full length. next shot: back to 2e19, like shot #9. |
| Jun 13 2000 03:03:22:310PM | 1000613017 | Steve Wolfe | shot#17: back to 2e19, like shot #9. Another heat trip before this shot. disrupts at .97sec, no h-mode up to 2MW, nl4=2.0e19. lose the sawteeth at .6sec. next shot: try turning rf on at constant power |
| Jun 13 2000 03:18:42:030PM | 1000613018 | Steve Wolfe | shot#18: back to 2e19, like shot #9. try turning rf on at constant power at 0.5sec disrupts at .74sec, no h-mode, 2.2MW next shot raise nl4 to 3.5e19, leave rf the same. |
| Jun 13 2000 03:30:53:107PM | 1000613019 | Steve Wolfe | shot#19: raise nl4 to 3.5e19, leave rf the same. fizzle. Not surprising, considering the level of shit on the RGA. next shot: try again |
| Jun 13 2000 03:56:47:873PM | 1000613020 | Steve Wolfe | shot#20: raise nl4 to 3.5e19, leave rf the same. disrupts at .87sec, no hmode, lose sawteeth at .62sec back to 6e19, like shot 16, to try to get out of this low-density disruption/fizzle cycle. |
| Jun 13 2000 04:10:24:140PM | 1000613021 | Steve Wolfe | shot#21: back to 6e19, like shot 16, to try to get out of this low-density disruption/fizzle cycle. fizzle. Should have dropped the fill. probably wouldn't have helped; current gets above 30kA @10msec, then stalls. CII=.005mW/cm2/ster, no burnout. try again. |
| Jun 13 2000 04:24:36:920PM | 1000613022 | Steve Wolfe | shot#22: back to 6e19, like shot 16, to try to get out of this low-density disruption/fizzle cycle. plasma, disrupts at 1.54, some runaways early h-mode dies at .68sec. drop to 4e19, program an inner gap scan to limited (.6 to 1.2sec) |
| Jun 13 2000 04:49:21:357PM | 1000613023 | Steve Wolfe | shot#23: drop nl4 to 4e19, program an inner gap scan to limited (.6 to 1.2sec) clearin from .0037 to -.014; rcur from .668 to .659 drop fill to 22msec disrupts at .7sec, before got much of a ramp. two tiny h-modes at .61, .66. |
| Jun 13 2000 05:10:40:843PM | 1000613024 | Steve Wolfe | shot#24: drop puff to 20msec and repeat. plasma disrupted at 1.4sec, made it through the ramp. lots of ditethery transitions that don't last. stored energy drops after .87sec, when sawteeth get lost. rf constant. left gap went to zero at 1.2sec, as programmed, right gap grew to 2cm, which implies I overcompensated the rcur change. |
| Engineering Operator Comments | ||||
| Shot | Time | Type | Status | Comment |
| 1 | 09:00:04:500AM | Test | Ok | OH Coax Test |
| 2 | 09:14:48:560AM | Test | Ok | TF 50Kamp Test |
| 3 | 10:05:04:560AM | Plasma | Ok | |
| 4 | 10:25:55:357AM | Plasma | Ok | |
| 5 | 10:44:42:013AM | Plasma | Ok | |
| 6 | 11:04:04:920AM | Plasma | Ok | |
| 7 | 11:23:30:123AM | Plasma | Ok | |
| 8 | 11:43:34:140AM | Plasma | Ok | |
| 9 | 12:03:36:530PM | Plasma | Ok | |
| 10 | 12:23:29:903PM | Plasma | Ok | |
| 11 | 12:38:41:373PM | Plasma | Ok | |
| 12 | 12:58:38:000PM | Plasma | Ok | |
| 13 | 01:19:35:153PM | Plasma | Ok | |
| 14 | 01:35:24:013PM | Plasma | Ok | |
| 15 | 01:56:01:013PM | Plasma | Ok | |
| 16 | 02:14:34:123PM | Plasma | Ok | |
| 17 | 02:48:14:500PM | Plasma | Ok | |
| 18 | 03:09:03:340PM | Plasma | Ok | |
| 19 | 03:26:06:420PM | Plasma | Ok | |
| 20 | 03:43:06:467PM | Plasma | Ok | |
| 21 | 04:02:11:153PM | Plasma | Ok | |
| 22 | 04:18:32:047PM | Plasma | Ok | |
| 23 | 04:38:00:077PM | Plasma | Ok | |
| 24 | 04:58:04:687PM | Plasma | Ok | |