| Miniproposals | ||||||||||||
|
| Operators | |
| Session leader(s): | Bruce Lipschultz,Steve Wukitch |
| Physics operator(s): | Ron Parker |
| Engineering operator(s): | Bill Cochran |
| Engineering Operator Run Comment |
| Progress on 2 mps-ICRF conditioning and understanding the MO sources. Li |
| Session Leader Plans |
| Physics Operators Plans |
| Session Leader Summaries |
| Entered: Jul 7 2004 03:49:23:303PM |
| Author: To Be Determined |
| Run: 1000512 Mini proposals: mps 225 (Mo sources/screening) and 268 (ICRF conditioning) SL: Bruce Lipschultz and Steve Wukitch PO: Ron Parker EO: Bill Cochrane Purpose: To try and isolate the relative contribution Mo sources from the inner wall, outer limiter/antennas, and divertor to the core Mo levels. We hope to be able to determine the screening of the Mo source from these different locations. The final aspect of the updated 225 is to understand whether rf sheath rectification is playing a role in the generation of impurities from the antenna. As part of the latter goal we have previously measured floating potential and inferred the plasma potential. We will do tht as well this run but supplement that with an attempt at directly measuring the plasma potential with an emissive probe(s) mmounted on the sides of the AB limiter. The electronics were just installed last night and we will try it today. To compare the relative sources from the different antennas we can do some work, comparing J4 and D (E is not working today). With regard to conditioning of the antennas, we will endeavor to minimize impurity production and maximize heating by varying the plasma height and strap phasing. We will compare the heating of the J antenna to D for these variations as well. Summary: The emissive probes appeared to work today. Midway through the run (shot 13) Bill Burke was able to install the second electronics board and it worked immediately! With that we were able to determine that the potentials measured by the probes (one on each side of the AB limiter) each correlate with the antennas that field lines connect them to. In the case of the A side of the limiter this means the J4 antenna, for the B-side of the limiter this means the D-antenna. We verified that the probes are measuring something approximating the plasma potential by turning off the heating current and taking data with probes in floating mode. In this case the potentials were much lower, of order 10's of volts, sometimes negative. This is to be compared to when the current was on and the probe emitting - there we measured typically 50-200 volts of potential, once as high as 400V. The plasma potential was of the level described above when the corresponding antenna was on. However, there was much variation in the measured potetials during a shot. Looking at L- and H-mode shots as well as constant power, L-mode shots Brian and I feel that it is likely that the variation we see in the range 60-300V could be due to variations in field lines that map to the probe. So, as the equilibrium changes (confinement) or just the slight variations that occur during a shot, the potentials vary. In any case the measured potentials verify that sheath rectification does occur, and that the potentials are substantial. Two or three times ionized boron would be at the peak of its sputtering yield for impact on Mo. Replacement of the Mo tiles with BN should reduce the sheaths created. We greatly appreciate Bill Burke's efforts in getting the getting this diagnostic working and testing it. The results on the comparison of antenna sources was as expected. The good news is that the Mo source rate and effect on the core by the J antennas is considerably reduced from last run period. However, the source rate from the J antennas and the effect on the core (n_mo) were typically a factor of 2-3 larger than with the D-antenna for equivalent launched power. The radiated power in the core did not increase by these same margins. That argues that the core radiation is not dominated by Mo, at least before turning on the antennas. The increase in core radiation, for L-mode plasmas and 1.2 MW of RF (limited to stay out of H-mode) was 3-400 kW for J4 and about half that for D. In H-mode, the radiated power is much higher, but it is harder to determine how much to attribute to the RF. Speaking of injections, they were most noticable on the camera views when the J-port antennas induced an H-mode. The two main locations for the injections, according to the camera views, (which can't see much of J4) were the J-port Faraday screen and the protection tiles on the lower corner, closest to H-port. Chomex has views of J4 only and saw significant molydenum source rates coming from the top of J4. The shots that had the largest injections of Moly, according to Chromex, were 005, 009, 101 and 22 with peak moly sources rates of 2e18, 3e18, 8e17 and 2e17 respectively. The injections often seemed to correlate between camera and Chromex. So the question arises with respect to the Chromex and the camera view of J - Is the light seen on the camera due to some injection from J4 coming into the field of view of the camera or vice versa? We do not know the answer. Also, during these shots the McPherson observed a Li-like Ti line (309.1 A) from 1.0 - 1.4 seconds for the first three above mentioned shots. The peak source rates occur more when the injections come from the lower protection tiles then when injections are observed coming from the screen. Shot specifics: Shot 1: This went fine. 1 MA, nel04 ~ 1. J3+ J4 stepping up to 2 MW total, followed by D ramping to 1 MW. In and out of H-mode (ELM-free). Core Mo goes up with last step in J and entry to H-mode - level 1-2e15 m^-3. Shot 2: This went fine. 1 MA, nel04 ~ 1. J3+ J4 stepping up to 2 MW total, followed by D ramping to 1 MW. In and out of H-mode (ELM-free). Core Mo goes up with last step in J and entry to H-mode - level 1-2e15 m^-3. Injection of Mo ends H-Mode. Shot 3: several large injections (3-4 e15 m^3), one of which dropped out J3. Still slightly reducing kappa. It was 1.67 on shot 1. Now it is 1.62. Will repeat. Shot 4: still had problems with RF staying on. But got H-mode. Mo level analysis failed. Shot 5: Back to 'normal' plasma kappa. Get probe set up for measurements. Biggest injection so far from J4. 5e15 core density. Shot 6: fizzle Shot 7: fizzle, delay for computer problem. Shot 8: Same as 5 but emissive probe switched from floating to plasma potential measurement. Saw increase during RF. Next vary phasing. Shot 9: 0 :Pi: 0.7Pi: -.3Pi phasing and emission turned on. Saw large voltages on the probe during the H-modes (300 V), much lower in L-mode (~ 60 V), Mo injections still occurring. Shot 10: 0 :Pi: 0.9Pi: -.1Pi. No H-mode. voltages on emissive probe stay in the 60 V range . No big injections as well. Shot 11: 0 :Pi: -.1Pi: 0.9Pi. H-mode. voltages on emissive probe jumping to 200v during H-modes, 50 V during L-mode. Radiated power still large - 2 MW. Shot 12: Only J4. Saw potentials on the J-facing emissive probe reaching 300 V during H-mode, 80 V during L-mode. Next shot we hope to have both probes on the limiter working. Mo levels with just the one antenna were not particularly high. - 1.5e15 before an injection. Shot 13: J4 steps 0.5, 0.9, 1.2 MW followed by D in several steps. We got an H-mode with D at 500 kW - ELM-free. We also saw the proper correlation with the new emissive probe facing D: When D is on we saw potential increases in the SOL in the range 50-200 V with D ONLY when D was on. Similar for the probe facing J (correlating with J4) Shot 14: J4 steps 0.5, 0.7, 1.2 MW followed by D in several steps. We got an H-mode with D at the step from 500 -800 kW - ELM-free. Similar voltages to last shot. Shot 15: J3 steps 0.5, 0.7, 1.2 MW followed by D in several steps. We got an H-mode with D at the step from 500 -800 kW - ELM-free. Similar voltages to last shot. Essentially no voltage on the A-side emissive probe which makes sense in that field lines connect it to J4 not to J3. Shot 16: J3 steps 0.5, 0.7, 1.2 MW followed by D in several steps. No H-mode because the plasma was limited on the inner wall. Potentials measured by the emissive probes were 200 V for J3 and 100 or so for the probe facing D. Shot 17: Turned off current through emissive probe and repeat shot 16. The probe should be in floating mode and measure lower voltages. This in fact what we saw. The voltage was close to zero on the probe facing J, ~-20 V on the one facing D. Shot 18: Probes back in emissive mode. Compare J3 and D. Very little potential on the emissive probe facing J, but we don't expect much w/respect to J3 rather than J4. The usual plasma potential measured on the D-facing emissive probe. Note that these plasmas are still limited on the inner wall. Shot 19: Compare J4 and D but reverse the order putting D first to address a concern regarding the density rise at the end of the shot. 300 volt potentials on the emissive probe facing J4 even though plasma is not in H-mode. J4 leads to higher Mo core content than D. The radiated power does not appear to be so different which does not make sense. Shot 20: Diverted again. Constant J4 power at 1 MW for 1 second to look for possibility that there is an energy effect (heating - evaporation) leading to Mo sources. We did not see a joule effect on this shot. No H-mode so radiated power stayed constant. Potentials measured by probe between 100 and 200 V. Shot 21: Tried for 1.5 MW out of J4 - got 1.7 MW which lasted until an H-mode tried to kick in. Then J4 overloaded and tripped. Plasma potentials were 300 V before the trip. Radiated power was not bad - 1. MW before the trip as well. Shot 22: J3 did not go so we just had J4 at 1.5 MW. No H-mode. Mo injections from J4 starting at 1.2 seconds or so. 100-300 V plasma potentials measured, |
| Physics Operator Summaries |
| Entered: Jul 7 2004 04:37:10:740PM |
| Author: To Be Determined |
| Run plan for 1000512 SL:Lipschultz/Wukitch PO:Parker Run begins at 9:00 and ends at 17:00 Engineering Setup ECDC overnight in D2, turnoff 2 hours before beginning of run Power setup as in shot 10005100021 OH and TF fizzle delays of 300 and 400 ms Gas setup: Fill B-top 6 psi D2 Hybrid enabled Fill B-side lower with 1 psi Ar Hybrid enabled Leave B-side upper as is Hybrid DISABLED Fill C-side 30 psi D2 Hybrid enabled Leave J-bottom as is Hybrid DISABLED Following Gate Valves enabled, assuming no vacuum problems: VUV,ECE, DNB Shot plan for 1000512 The purpose is to make progress on 2 mps - ICRF conditioning and understanding the Mo sources. Start by reloading 1000510021 for first shot. (1) Optimize plasma shape. This means reducing ellipticity for several shots. (2) Vary J RF power (J3 followed by J4) and look to understand Mo eruption that occurred on ramping J3 & J4 shots. Is this a power effect, or a energy (power x time)? Is it dependent on phase (shot 14, the worst case, had 0, Pi, -.85Pi, .15Pi phasing). We will need a constant RF power in square wave form with 'bad' phasing. Vary the amount of power in each antenna from shot to shot. If it shows up immediately at the beginning of the RF pulse as the power is raised, then we have an RF field effect. If it occurs later in the pulse it is probably a heating effect. (6-8 shots) (3) Compare the Mo source from the different antennas. Here we need steps in the RF power in an isolated antenna, varying up to the H-mode threshold. Staying in L-mode keeps the core impurity confinement from muddying the interpretation. The RF power steps need to be aabout 165 ms long, allowing for 3 steps per antenna and 2 antennas in one shot. Brian will be measuring the plasma profiles in the region of the antennas and we will get floating potential by that method. I will try and get the emissive probe working for measurement of the plasma potential for correlation with the RF power and phase. RF needs to specify the magnetic field. No Argon unless ok'd by Session leaders Run Summary We began by loading shot 1000510021 which nicely reproduced. Then, in line with the run plan, we lowered the elongation, principally by raising the lower X-point. The X-point was then varied up and down 5mm per shot over the next few shots. Two shots then fizzled as described in the log but plasma operation resumed with shot 8. Shots 8-15 were essentially identical as far as the plasma control system was concerned. During these shots the RF was varied by changing antennas and power levels in stair-case fashion. Measurements of the float- ing potential in the SOL were made by B. Labombard with emissive probes. Then, with shot 16 the plasma was programmed to be limited in order to prevent the transition to an H-Mode. Identical limited plasmas were produced in Shots 16 - 19 with no H-Mode. Again, the RF was varied in antenna used and power. Finally, shots 20- 22 were reprogrammed to be diverted and the RF configuration again changed shot to shot. Brief H-Modes were produced by the J-port antenna. Overall, the machine ran very well with 20 shots running exactly as programmed and only two fizzles, at least one of which was due to a technical problem. |
| Session Leader Comments | |||
| May 12 2000 09:49:00:810AM | 1000512001 | Bruce Lipschultz | Shot 1: This went fine. 1 MA, nel04 ~ 1. J3+ J4 stepping up to 2 MW total, followed by D ramping to 1 MW. In and out of H-mode (ELM-free). Vore Mo goes up with last step in J and entry to H-mode - level 1-2e15 m^-3. |
| May 12 2000 10:03:45:513AM | 1000512002 | Bruce Lipschultz | Shot 2: This went fine. 1 MA, nel04 ~ 1. J3+ J4 stepping up to 2 MW total, followed by D ramping to 1 MW. In and out of H-mode (ELM-free). Core Mo goes up with last step in J and entry to H-mode - level 1-2e15 m^-3. Injection of Mo ends H-Mode. |
| May 12 2000 10:23:17:030AM | 1000512003 | Bruce Lipschultz | Shot 3: several large injections (3-4 e15 m^3), one of which dropped out J3. Still slightly reducing kappa. It was 1.67 on shot 1. Now it is 1.62. Will repeat. |
| May 12 2000 11:11:12:937AM | 1000512005 | Bruce Lipschultz | Shot 5: Back to 'normal' plasma kappa. Get probe set up for measurements. Biggest injection so far from J4. 5e15 core density. |
| May 12 2000 11:53:56:153AM | 1000512006 | Bruce Lipschultz | Shot 6: fizzle |
| May 12 2000 11:54:33:543AM | 1000512007 | Bruce Lipschultz | Shot 7: fizzle, delay for computer problem. |
| May 12 2000 12:18:46:030PM | 1000512008 | Bruce Lipschultz | Shot 8: Same as 5 but emissive probe switched from floating to plasma potential measurement. Saw increase during RF. Next vary phasing. |
| May 12 2000 12:45:24:123PM | 1000512009 | Bruce Lipschultz | Shot 9: 0 :Pi: Pi: 0 phasing and emission turned on. Saw large voltages on the probe during the H-modes (300 V), much lower in L-mode (~ 60 V), Mo injections still occurring. |
| May 12 2000 01:03:39:310PM | 1000512010 | Bruce Lipschultz | Shot 10: 0 :Pi: 0.9Pi: -.1Pi. No H-mode. voltages on emissive probe stay in the 60 V range . No big injections as well. |
| May 12 2000 01:20:54:013PM | 1000512011 | Bruce Lipschultz | Shot 11: 0 :Pi: -.1Pi: 0.9Pi. H-mode. voltages on emissive probe jumping to 200 v during H-modes, 50 V during L-mode. Radiated power still large - 2 MW. |
| May 12 2000 02:03:09:233PM | 1000512012 | Bruce Lipschultz | Shot 12: Only J4. Saw potentials on the J-facing emissive probe reaching 300 V during H-mode, 80 V during L-mode. Next shot we hope to have both probes on the limiter working. Mo levels with just the one antenna were not particularly high. - 1.5e15 before an injection. |
| May 12 2000 02:16:30:467PM | 1000512013 | Bruce Lipschultz | Shot 13: J4 steps 0.5, 0.9, 1.2 MW followed by D in several steps. We got an H-mode with D at 500 kW - ELM-free. We also saw the proper correlation with the new emissive probe facing D: When D is on we saw potential increeases in the SOL in the range 50-200 V with D ONLY when D was on. Similar for the probe facing J (correlating with J4) |
| May 12 2000 03:13:05:153PM | 1000512015 | Bruce Lipschultz | Shot 15: J3 steps 0.5, 0.7, 1.2 MW followed by D in several steps. We got an H-mode with D at the step from 500 -800 kW - ELM-free. Similar voltages to last shot. |
| May 12 2000 03:16:21:250PM | 1000512016 | Bruce Lipschultz | Shot 16: J3 steps 0.5, 0.7, 1.2 MW followed by D in several steps. No H-mode because the plasma was limited on the inner wall. Potentials measured by the emissive probes were 200 V for J3 and 100 or so for the probe facing D. |
| May 12 2000 04:18:32:590PM | 1000512018 | Bruce Lipschultz | Shot 18: Probes back in emissive mode. Compare J3 and D. Very little potential on the emissive probe facing J, but we don't expect much w/respect to J3 rather than J4. The usual plasma potential measured on the D-facing emissive probe. Note that these plasmas are still limited on the inner wall. |
| May 12 2000 04:43:55:187PM | 1000512020 | Bruce Lipschultz | Shot 20: Diverted again. Constant J4 power at 1 MW for 1 second to look for possibility that there is an energy effect (heating - evaporation) leading to Mo sources. We did not see a joule effect on this shot. No H-mode so radiated power stayed constant. Potentials measured by probe between 100 and 200 V. |
| May 12 2000 05:05:00:107PM | 1000512021 | Bruce Lipschultz | Shot 21: Tried for 1.5 MW out of J4 - got 1.7 MW which lasted until an H-mode tried to kick in. Then J4 overloaded and tripped. Plasma potentials were 300 V before the trip. Radiated power was not bad - 1. MW before the trip as well. |
| May 12 2000 06:12:51:483PM | 1000512022 | Bruce Lipschultz | Shot 22: J3 did not go so we just had J4 at 1.5 MW. No H-mode. Mo injections from J4 starting at 1.2 seconds or so. 100-300 V plasma potentials measured, |
| Physics Operator Comments | |||
| May 12 2000 10:05:52:873AM | 1000512001 | Ron Parker | First shot was successful. Setup to reproduce conditions of shot 1000510021. In line with run plan, next shot will be similar, but ZXU lowered by 5 mm and ZXU raised by 5mm |
| May 12 2000 10:03:38:187AM | 1000512002 | Ron Parker | This shot was programmed to move the lower X-point 5 mm higher. Also the upper X point was moved by same amount. Net result should have been a lowering of elongation. Shot had slightly lower elongation. Next shot: ZXL increased by 5mm. |
| May 12 2000 10:22:43:890AM | 1000512003 | Ron Parker | In this shot, ZXL was raised again by 5 mm to further reduce elongation. Shot had an injection and will be repeated. |
| May 12 2000 10:35:53:467AM | 1000512004 | Ron Parker | Shot ran as programmed, with ZXL the same as in previous shot. In next shot, the settings for shot 1000512001 will be restored, but ZXL will be set 5 mm lower than in this shot. |
| May 12 2000 11:11:41:920AM | 1000512005 | Ron Parker | Shot ran well. ZXL moved as programmed. In next shot an additional ramp in ZXL has been programmed from 1-1.4s, moving the x-point further down by 5mm at ~1.4 s. Bob Granetz will take over as PO after this shot. |
| May 12 2000 11:26:22:077AM | 1000512006 | Ron Parker | (Granetz is making this entry) Shot 06 -- Fizzle. Tiny difference in Br0. Bill Cochran reports that there was a small problem with EF2L, but I don't think it was enough to cause the fizzle. Next shot: change Br0 offset by +0.0004 T |
| May 12 2000 11:54:54:030AM | 1000512007 | Ron Parker | (Granetz is making this entry.) Shot 07 -- Fizzle. There was a delay between CHECK and PULSE states, due to a minor problem in the alternator house, and this apparently let to a reduction in the gas load coming from the DNB, which resulted in a low fill pressure at breakdown. Next shot: no PCS changes. |
| May 12 2000 11:56:10:013AM | 1000512007 | Ron Parker | (Granetz is making this entry.) The next shot is delayed due to a computer crash. |
| May 12 2000 12:08:58:700PM | 1000512008 | Ron Parker | (Granetz is making this entry.) Shot 08 -- Plasma. Good shot. Prf is up to 2 MW. Several H-modes, H-alpha looks more like ELMfree, but ne looks like EDA. |
| May 12 2000 01:33:50:233PM | 1000512009 | Ron Parker | R. Parker back as operator. Shot ran well as programmed. No changes to plasma control for next shot. |
| May 12 2000 01:24:56:623PM | 1000512010 | Ron Parker | Shot ran as planned. |
| May 12 2000 01:25:54:780PM | 1000512011 | Ron Parker | Shot ran as planned without changes. |
| May 12 2000 01:27:47:200PM | 1000512012 | Ron Parker | Shot ran without changes. Operator error: hold was lifted before RF'ers were ready. Cell entry to tend to emissive probe electronics. |
| May 12 2000 02:05:56:670PM | 1000512013 | Ron Parker | Shot ran as programmed with no changes. Good H-mode with D-port antenna, but no sign of H-mode at same power with J port. (J port pulse preceeded D-port pulse.) |
| May 12 2000 02:36:34:577PM | 1000512014 | Ron Parker | Shot ran well, H-mode a little more erratic than previous shot. Went into H-mode at 0.5 MW. No plasma control changes. For next shot, SL requests lower X point to be moved in by 5 mm |
| May 12 2000 03:03:02:497PM | 1000512015 | Ron Parker | Shot 15 ran again as programmed. Startup remains reliable. Next shot will be programmed for a limited plasma to avoid H-mode. Clearin was decreased 16 mm and R was decreased 8 mm. |
| May 12 2000 03:10:38:687PM | 1000512016 | Ron Parker | Shot ran just as planned, very slightly limited, but enought to prevent the L-H transition. Next shot will be programmed to repeat (no changes). |
| May 12 2000 03:43:50:420PM | 1000512017 | Ron Parker | Shot ran well, remaining limited. Next shot will be the same as far as plasma control is concerned, but J3 will be used instead of J4. |
| May 12 2000 03:58:16:543PM | 1000512018 | Ron Parker | This shot had a major injection around 0.8 s. Next shot: Back to J4 antenna, and switched timing--D port first, then J4. |
| May 12 2000 04:20:43:497PM | 1000512019 | Ron Parker | Shot 19 ran well. Plasma stays limited and in L-Mode. Next shot will revert to diverted operation--loaded from shot 15. J4 will do a solo number for 1 s. |
| May 12 2000 04:35:33:590PM | 1000512020 | Ron Parker | Shot 20 ran as programmed (diverted). Short appearance of an H-Mode from J-port antenna. Next shot, same plasma control settings and more power from J4. |
| May 12 2000 04:55:04:793PM | 1000512021 | Ron Parker | Shot 21 ran well, but the RF kicked out (overcurrent trip) shortly after a transition into H-mode. The next and last shot of the run will be identical as far as the plasma control system is concerned and with somewhat lower RF power. J4 power be backed off and J3 will be pulsed as well. |
| May 12 2000 05:26:00:327PM | 1000512022 | Ron Parker | Shot ran as programmed with brief evidences of H-Mode. |
| Engineering Operator Comments | ||||
| Shot | Time | Type | Status | Comment |
| 1 | 09:16:00:873AM | Plasma | Ok | |
| 2 | 09:47:20:607AM | Plasma | Ok | |
| 3 | 10:04:40:733AM | Plasma | Ok | |
| 4 | 10:22:55:060AM | Plasma | Ok | |
| 5 | 10:43:51:090AM | Plasma | Ok | |
| 6 | 11:12:28:373AM | Plasma | Ok | |
| 7 | 11:30:14:340AM | Plasma | Ok | Fizzle |
| 8 | 11:59:25:467AM | Plasma | Ok | Plasma |
| 9 | 12:18:45:403PM | Plasma | Ok | |
| 10 | 12:37:58:653PM | Plasma | Ok | |
| 11 | 12:59:46:610PM | Plasma | Ok | |
| 12 | 01:19:12:293PM | Plasma | Ok | |
| 13 | 01:55:31:157PM | Plasma | Ok | |
| 14 | 02:15:39:857PM | Plasma | Ok | |
| 15 | 02:39:07:247PM | Plasma | Ok | |
| 16 | 03:00:40:420PM | Plasma | Ok | |
| 17 | 03:20:03:840PM | Plasma | Ok | |
| 18 | 03:43:21:780PM | Plasma | Ok | |
| 19 | 04:03:11:560PM | Plasma | Ok | |
| 20 | 04:22:39:687PM | Plasma | Ok | |
| 21 | 04:42:56:357PM | Plasma | Ok | |
| 22 | 05:01:02:310PM | Plasma | Ok | |