| Miniproposals | ||||||||||
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| Operators | |
| Session leader(s): | Stefano Bernabei |
| Physics operator(s): | Ron Parker |
| Engineering operator(s): | Sam Pierson,Bill Parkin |
| Engineering Operator Run Comment |
| MP 418 L/H Coupling Study EO Pierson PO Parker SL Bernabei |
| Session Leader Plans |
| Physics Operators Plans |
| Entered: Apr 14 2005 09:16:21:673AM |
| Author: Ron Parker |
| Engineering Setup for Thursday, 14 April 2005 MP 418 Lower Hybrid Coupling Studies (Cont'd) Session Leader: Bernabei Physics operator: Parker Overnight discharge clean in D2, bake at 60 C. Run Begins at 09:00 and ends at 17:00 Power sytems as on 1050331 A-coils in standard configuration (lock mode suppression) +Dtop -Dbot -Jtop +Jbot (same as 1050316) Gas Setup: fill B-top with 6 psi D2 hybrid enabled (PG4) fill B-side lower with 2 psi Ar Hybrid enabled (PG1) leave B-side upper with He3 Hybrid disabled fill B-main (C-side) with 30 psi D2 Hybrid enabled (PG3) leave J-bot Hybrid disabled (PG2) Enable the following: ECE gate valve, Z-bolo shutters VUV gate valve NO ICRF!! Lower Hybrid 3 carts ready to pulse, +90 degree phasing. Pulse length up to 20 msec power per klystron up to 20 kW The run will focus on basic LH coupling studies. Plasma conditions will be routine, 5.4 T, 700 kA, single null. Lowish density. We may want to raise field to enhance penetration. The plan is to study coupling and any apparent plasma phenomena associated with LH at 4 coupler positions; at each coupler position 4 phase increments will be set, namely +60, +90, +120 and +150 degrees. |
| Session Leader Summaries |
| Entered: Apr 19 2005 09:00:54:500AM |
| Author: J. Randall Wilson |
| Physics summary for April 14 run.
LHCD / Stefano Bernabei The plan was to look at coupling (reflection as a whole and in individual waveguides) launching waves in the counter direction (anti-current drive). The results should either confirm that the phase calibration is correct, or that we are not launching the programmed spectrum. In addition we have obtained very valuable information on optimizing coupling. The day's run was succesfull, we obtained the data we wanted and had some spare time to perform a very important test. Two weeks ago we performed a phase scan at three coupler positions, one of them is shown in the plot As expected, best coupling is always at DF~90° Repeating this scan in counter-CD the result should be ideally the same. we did the scan at 1 and 3 mm distances. We added two phases, DF=30° and 135°, in order to have a more complete curve to confirm the trend. There is a caveat: the plot has been obtained while keeping the high power phase shifters fixed at DF=90°, which means that only the 90° phasing is technically correct (in this case in fact if the phase between two adjacent klystrons is programmed to be 90° there is a regular 90° phase difference across the whole array). For the other phasings, an appropriate phase difference between adjacent klystrons is needed in order to have the requested spectrum. This brings to the last experiment of the day: we adjusted all the power phase shifters in order to produce a DF=150° regular phase progression to be compared to the similar spectrum obtained keeping DF=90° fixed between waveguides n and n+1. We chose 150° because is a phasing mosly affected by the approximation. This test is of great importance if it shows that the two methods of phasing coincide: when it will be needed to change phase, it will not be required to open the door and spend ~half an hour to adjust the high power phase shifters. Naturally, a great deal of analysis is need at this point. Arcing. Arcing reappeared, but later in the morning it seemed to weaken. Instead of appearing immediately at the RF turn on it moved toward the end of the pulse and seemed weaker. But there were two very puzzling things. 1 the arcs were always in the top array, like two weeks ago: density in front of the coupler is wonderfully constant, as measured by th probes so there is no apparent reason. 2 two weeks ago, arc was in wg 16. Yesterday morning was in wg 19, then it subsided, and appeared in wg 12. The first horrible thought is that the windows have been coated by titanium or braze material. But in this case I suppose that reflection would be total, which I don't believe it is. Anyway, we have to address this problem with priority, and if we convince ourselves that coating does not occurr, we should aggressively condition the couplers. |
| Physics Operator Summaries |
| Entered: Jan 25 2012 01:08:05:963PM |
| Author: Ron Parker |
| Run 1050414 was devoted to completing the LH phase scan begun on 1050331. For this run,
the phase was mainly scanned in the counter current drive direction, to compare with the co-current drive direction investigated in the 3/31 run. Toward the end of the run, the phase was set to be in the co direction and the mechanical phase shifter was set to produce a "pure" spectrum with 150 degree phasing. In the run, some difficulty was encountered with startup until S. Wolfe pointed out that BR was a bit too positive. After setting BR to -0.5 mT, startup issues were cured and the machine ran reliably (although the hards were a slight problem.) Data were collected and the run was successful in accomplishing the goals. While the LH antenna seems to be cleaning up, a more vigorous conditioning program needs top be implemented to increase the power. - |
| Session Leader Comments | |||
| Apr 14 2005 03:08:05:313PM | Stefano Bernabei | 1050414001
work with reversed phase, to compare refl. coeff. with CD phasing / start with 0.1 mm distance | |
| Apr 14 2005 09:44:48:500AM | 1050414002 | Stefano Bernabei | 1050414001
work with reversed phase, to compare with CD phasing start with +90 degrees fizzle 1050414002 +90 good no arcing |
| Apr 14 2005 10:47:26:047AM | 1050414005 | Stefano Bernabei | 1050414005
+90 faint breakdown: perhaps waveguide 19? we are running 10 msec pulse to minimize risk of arcing |
| Apr 14 2005 01:32:36:180PM | 1050414007 | Stefano Bernabei | 60 degrees good shot
breakdown: material flying out of top waveguide |
| Apr 14 2005 12:05:18:810PM | 1050414008 | Stefano Bernabei | 120 degrees good shot, no visible arcing, but big step in reflection in wg 19 and 20 |
| Apr 14 2005 12:14:47:040PM | 1050414009 | Stefano Bernabei | dud |
| Apr 14 2005 03:40:36:260PM | 1050414010 | Stefano Bernabei | 150 deg good shot, no visible arc / no sign of arcing in reflection, but
flying material from top array |
| Apr 14 2005 01:21:44:173PM | 1050414013 | Stefano Bernabei | 135 phase intermediate between 120 and 150 to confirm the trend in rel. coeff.
double RF power: arc late in the pulse in wg 19 1nd 21 |
| Apr 14 2005 02:07:38:277PM | 1050414015 | Stefano Bernabei | 135 deg good shot, distance plasma limiter changed to 3.5 mm |
| Apr 14 2005 02:18:26:397PM | 1050414016 | Stefano Bernabei | 150 deg good shot no sign of arcing: is it being conditioned? |
| Apr 14 2005 02:35:58:367PM | 1050414017 | Stefano Bernabei | 120 deg / god shot / arcing in 19-20 "counter arcing?" in wg 18-21 |
| Apr 14 2005 03:02:56:380PM | 1050414018 | Stefano Bernabei | 90 deg arcing in 19-20 immediately after turn-on |
| Apr 14 2005 02:59:34:943PM | 1050414019 | Stefano Bernabei | 60 degrees good but arcing |
| Apr 14 2005 03:45:23:777PM | 1050414020 | Stefano Bernabei | 30 deg: relct. coefficient should be much higher |
| Apr 14 2005 04:39:16:133PM | 1050414021 | Stefano Bernabei | MOVE ALL HIGH POWER PHASE SHIFTERS: COMPARE IRREGULAR PHASING (gray spectra)
WITH REGULAR PROGRESSIVE PHASING. We choose 150 deg. because is the spectrum most affected among the gray spectra (90 deg is zero modification) ~10 kW per guide / good shot / disappointing arcing / 3.5 mm dist. |
| Apr 14 2005 05:03:16:490PM | 1050414022 | Stefano Bernabei | same shot 150 / double power ~20 kW per guide
OK / strong arc in waveguide ~14 ?? see film |
| Apr 14 2005 05:06:25:347PM | 1050414023 | Stefano Bernabei | 150 deg / same settings / 30 kW per guide 5 msec pulse
shot OK / same waveguide arcing last shot of the day |
| Physics Operator Comments | |||
| Apr 14 2005 09:30:11:173AM | 1050414001 | Ron Parker | First shot was a dud due to operator error. For shot 2, segment 1 drom 4/13/05 will be loaded. |
| Apr 14 2005 09:43:45:797AM | 1050414002 | Ron Parker | Shot 2 ran well and LH data for 90 deg phasing was aquired. Next shot will be a repeat. |
| Apr 14 2005 10:14:10:237AM | 1050414003 | Ron Parker | Shot 3 was a dud due to a failure of magnetic signal F25. Hopefully short pause while this is checked out. Coil checked out OK. We'll try again and see if it fixed itself. |
| Apr 14 2005 10:31:48:620AM | 1050414004 | Ron Parker | Shot 4 disrupted early -- reasons unknown. Runaways high, for next shot fill pressure will be increased from 20 to 23 ms. |
| Apr 14 2005 10:43:25:873AM | 1050414005 | Ron Parker | Shot ran OK, no apparent reason for improvement over shot 3. Phasing was +90 deg. On next shot, phasing will be +60 deg. Also, density was very low toward end of shot. We'll try to keep nl_4 at 5e19 during shot and move RCUR a bit inwards during rampdown. |
| Apr 14 2005 11:59:38:637AM | 1050414006 | Ron Parker | Shot 6 was a dud. |
| Apr 14 2005 11:56:13:403AM | 1050414007 | Ron Parker | Shot 7 ran well, data collected for 60 deg approx CCD phasing. |
| Apr 14 2005 12:10:54:137PM | 1050414008 | Ron Parker | Shot 8 ran well, LH data collected for 120 deg CCD approx phasing. |
| Apr 14 2005 12:19:20:490PM | 1050414009 | Ron Parker | Shot 9 had a late breakdown and fizzled. |
| Apr 14 2005 12:39:57:960PM | 1050414010 | Ron Parker | Shot 10 ran OK, breakdown still a bit late. Data collected for 150 deg CCD approx phasing. |
| Apr 14 2005 01:12:12:010PM | 1050414011 | Ron Parker | Shot 11 ran and data collected for 135 deg CCD approx phasing. |
| Apr 14 2005 01:15:13:343PM | 1050414012 | Ron Parker | Shot 12 was a dud. Decrease BR by 0.5 mT for next shot. |
| Apr 14 2005 01:33:50:880PM | 1050414013 | Ron Parker | Shot ran , this time RF power was increased to 200 kW. |
| Apr 14 2005 01:51:23:490PM | 1050414014 | Ron Parker | Shot 14 ran OK. Same conditions as in in Shot 13. Slight pause while coupler is pulled out to - 3mm from limiter. |
| Apr 14 2005 02:08:33:617PM | 1050414015 | Ron Parker | Shot 15 ran OK. First shot with grill 3 mm back from limiter. Phase 135 deg CCD, approx. |
| Apr 14 2005 02:33:37:090PM | 1050414017 | Ron Parker | Shot 16 ran, grill at -3mm. Phase is 120 deg CCD, approx Next shot, 90 deg, CCD, approx. |
| Apr 14 2005 02:43:11:230PM | 1050414018 | Ron Parker | Shot 18 ran OK, 90 phasing CCD, "exact". Next : 60 deg phasing, CCD approx. |
| Apr 14 2005 03:15:46:610PM | 1050414019 | Ron Parker | Shot 19 ran, 60 deg phasing CCD approx. Next: 30 deg, CCd approx. |
| Apr 14 2005 04:42:50:730PM | 1050414020 | Ron Parker | Shot 20 ran OK, data on 30 deg phasing collected. Next: 150 deg "ideal" CD phasing. |
| Apr 14 2005 04:41:46:400PM | 1050414021 | Ron Parker | Shot 21 ran well. Next: same phase as in 21, 20 kW (X2 power). |
| Apr 14 2005 05:20:15:810PM | 1050414023 | Ron Parker | Shot 23 ran OK, higher power, possibly 300 kW (according to the IQ detectors.) |
| Engineering Operator Comments | ||||
| Shot | Time | Type | Status | Comment |
| 1 | 09:19:39:057AM | Plasma | Ok | |
| 2 | 09:32:09:157AM | Plasma | Ok | |
| 3 | 09:44:43:343AM | Plasma | Ok | |
| 4 | 10:14:31:673AM | Plasma | Ok | |
| 5 | 10:32:04:510AM | Plasma | Ok | |
| 6 | 10:47:37:047AM | Plasma | Ok | |
| 7 | 11:43:54:680AM | Plasma | Ok | |
| 8 | 11:59:47:713AM | Plasma | Ok | |
| 9 | 12:13:06:613PM | Plasma | Ok | |
| 10 | 12:26:19:880PM | Plasma | Ok | |
| 11 | 12:42:05:607PM | Plasma | Ok | |
| 12 | 12:59:57:740PM | Plasma | Ok | |
| 13 | 01:13:38:260PM | Plasma | Ok | |
| 14 | 01:26:28:410PM | Plasma | Ok | |
| 15 | 01:56:15:520PM | Plasma | Ok | |
| 16 | 02:10:45:733PM | Plasma | Ok | |
| 17 | 02:27:29:160PM | Plasma | Ok | |
| 18 | 02:40:58:980PM | Plasma | Ok | |
| 19 | 02:53:35:790PM | Plasma | Ok | |
| 20 | 03:16:22:030PM | Plasma | Ok | |
| 21 | 04:28:55:243PM | Plasma | Ok | |
| 22 | 04:44:37:480PM | Plasma | Ok | |
| 23 | 05:02:33:647PM | Plasma | Ok | |