| Miniproposals | ||||||||||
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| Operators | |
| Session leader(s): | Peter Oshea |
| Physics operator(s): | Joseph Snipes |
| Engineering operator(s): | Vinny Bertolino |
| Engineering Operator Run Comment |
| mod icrf |
| Session Leader Plans |
| Physics Operators Plans |
| Session Leader Summaries |
| Entered: Jul 7 2004 03:49:14:820PM |
| Author: To Be Determined |
| ***************************** * Run 951214 Modulated RF heating ( Mode Conversion at 6.4 T , H[He3] plasmas ) * Session Leader : O'Shea * Physics Operator : Snipes ***************************** Plan is to revisit the best heating parameters from 950608 (shot #17 ). and to do a current scan at that density ( nel_04 ~ 1.0 ) while achieving good RF modulation at a variety of frequencies. ***************************** The run was not that successful, but much better than yesterday's. Run started a little late, had some vacuum problem's early on and a power glitch killed the run early. Through the bulk of the day, though, we had a good string of plasmas. Some decent heating shots were obtained (shots 8,13,14,15,18..) but only a couple with good modulation for transport. Convergence on good heating parameters was slow (trouble getting low enough target densities with appropriate ion ratios). One discovery was that E-port antenna seems to heat better than D-port ( see shot 15 ). Didn't have time to investigate this.... (note the E-port transmitter frequency is lower than D-port by ~500kHz. other differences?). Brian fired his scanning probe into shot 18. All shots at 800kA, target density ~0.9e20. No current scan. Shot summary follows: ***************************************************************** Shot Comment ==== ============================ 001 Hard xrays. Gas problems. Stopping to swap pumps. 002 Fizzle ...pressure is high....gas and vacuum probs Changing over vacuum roughing pumps.... 003 One puff of He (90v for 50ms) but with feedback so try the calib shot again. 004 He calib shot. Get a density rise from 0.6-->1.0 e19 with a 100ms He puff @90V. Central heating strongest at end of shot, long after He puff. 005 Going back to the feedback as of yor. Heating is weak. 006 Retry with RF reset. Hards. Runaway startup. Early returns indicate that the Helium is too low for good heating (lower than shot 4) so raising He program voltage from 32 to 55.... 007 Disrupts at 0.6. Doesn't make it to RF. He sig WAS higher. (Moly injection). 008 Shot went fine. Heating is moderate, but constant at least. HeII sig is level at about 11 (this on goes up to 11)) (see user9:[terry.scopes]heII.dat) throughout the heating. So my guess to raise the He was good i think. Upped preprogram voltage on he from 55 to 65. 009 Shot went, disrupts late. High plasma, work on equilibrium. RF coupling not good. Not tuned to helium change?.. Heating is similarly bad, though i think it's worse than can be explained from low RF power. Changing He preprogrammed voltage from 65 ---> 45 . cooling delay 010 Shot went better. Heating is better. For next shot, tweaking down the He (45--->40) increasing the mod freq to 62Hz.... 011 Plasma through RF. heating ok. evidence for off axis heating late. Not only are things not great, they seem to be changing with time throughout the shot. 012 Retry of above. heating and He a little lower. with same gas programming, lower HeII so things are sagging shot to shot. 013 Had upped the He to 50 (we think that at 40 it's almost off). RF has trouble coupling but heating is good when it does. Helium sig IS higher. Right now we are looking at the overall density. We are currently getting values higher than the programmed value, which is strange b/c usually we undershoot. For next shot, we kept He at 50...dropped preprog on H a little. 18 ...17 Hoping for shot to shot swing. 014 Heating is good early, for once, though not really good. RF crowbars. Some theories/observations:... Why is the 2nd pulse of RF more effective ? -comes from E-port antenna which is at 0.5 MHz lower freq. Golovato changing over to E port (from D) for main modulation train. Meanwhile Joe is trying to lower the density by lowering the preprogrammed voltages on both the H and He .... H 17....15 He 50...44 015 no reduction of density.... Heating is better....Eport antenna? 016 Burp due to fast cooling...turned off cooling...wait H 15...12 He 52 (don't want He to sag) (feedback off for He) Fizzle. 017 Retry. Plasma. HIGHER density (boo). Heating is pretty lousy. For next shot, must to reduce density!!! getting rid of preprogramming 018 He voltage to 42... density goes down! heating is pretty good but RF trips.....tuning is off He sig goes down..... maybe it's to be expected with the density change going to retry..... Power glitch 019,020,021,022.....fizzles. |
| Physics Operator Summaries |
| Entered: Jul 7 2004 04:36:55:613PM |
| Author: To Be Determined |
| ICRF Modulation in Hydrogen (He3 minority) at 6.45 T 951214 Engineer in Charge: Vince Bertolino Physicist in Charge: Joseph Snipes Session Leader: Peter O'Shea Setup: Discharge clean in hydrogen. Enable A side with hydrogen at 20 psi and B side upper with He3 at 20 psi. Setup as on shot 950608017 except that EF1 L and U limits should be [-7.5,5] and EF2 L and U limits should be 5.5. TF set to a flattop of 180 kA giving 6.45 T flattop. The run will start at 0.8 MA, 6.45 T, and nl04 = 9 x 10^19 m^-2. Then, we will perform a current scan from 0.6 MA to 1 MA, varying the He3 concentration to get the best ICRF heating. The ICRF will be modulated to look at the heating. At the beginning of the run, there were problems with the turbo pumps not pumping. So, we stopped and replaced the roughing pump behind the turbo pumps. That helped some, but the neutral pressures were always above 2.5 x 10^-6 Torr and often well above that. Once we got going again at nearly 11:00 am, we got a number of good shots with RF modulation and by adjusting the He3/H ratio some mode conversion heating was observed. Later we had some cooling problems that slowed down the shot rate considerably. Then, just as we were running shot 951214019, there was a power glitch that shut off local power including the room lights. The computers stayed on, but the power supplies were left in an unusual state and somehow air was puffed into the machine. After resetting a number of things including the cryo pump, the cooling system, gate valves, etc,, we tried again to get plasma. Shot 19 was retaken and it fizzled. Then, we tried again and it fizzled. Wolfe then noticed that the EFC supply was not working. We fired shot 21 and it also fizzled and EFC failed again. We then stopped to investigate the EFC problem. A couple of EFC tests showed that EFC seems to be O.K. Scorecard: 23 shots, 16 plasmas, 5 fizzles, 2 test shots Shot 1 : Copied shot 950608017 into segment 2 and shot 951212015 into segment 1. Extended pre-puff to 19 msec flattop since hydrogen should need higher pressure to breakdown than deuterium. He3 off for this shot. Starting at 0.8 MA, 6.45 T. Decent shot. Hard x rays 0.639 Roentgen. I forgot to enable B top for the pre-puff. There appears to be a H leak since the machine was at 6 x 10^-6 Torr before the shot and at 1 x 10^-5 long after the shot. The turbo pumps are not pumping the hydrogen away. So, we are stopping to swap out the roughing pump with the idea that its oil is saturated. Shot 2 : Enabled B top in H at 5 psi and B side upper in He3 at 20 psi. Put a He3 puff at 90 V from 0.5 to 0.55 sec. Fizzle. Shot 3 : Reduced pre-puff to 17 msec flattop. Good shot. More gas problems. Opening ballast on roughing pump to try to improve the pumping. Shot 4 : He3 puff set to 90 V from 0.6 to 0.7 sec. RF moved to 0.8 sec. Turned off density feedback from 0.5 sec. Turned off pre-programmed H gas after 0.5 sec. Good shot. Shot 5 : Reduced pre-puff to 15 msec. Copied gas pre-programming for A (K) side (H) and B side upper (He3) from shot 950608017 and turned the density feedback on again from 0.5 to 1.8 sec. Good shot. RF timing was from 0.8 to 1 sec. Shot 6 : Turned off pre-programmed density after 1 sec. RF timing moved to 0.65 sec. Hard x rays early and throughout the shot 0.9 Roentgen. Shot 7 : Raised pre-programmed He3 puffing from 32 V to 55 V throughout the flattop. Increased pre-puff to 17 msec. Raised early gas between 0.01 and 0.04 sec. Appears that a piece of Moly fell into the plasma. Shot 8 : Repeat. Good shot. Shot 9 : Raised He3 pre-programming to 65 V throughout the flattop. Good shot. Disrupted at 1.38 sec. Shot 10: Decreased ZCUR from -1.5 to -2 cm. Decreased ZXL by 1 cm to -1.8 cm. Reduced ZXU from 4 cm down to 2 cm and ramped it to -2 cm by 1.8 sec during the rampdown. Decreased He3 pre-programming to 45 V during the flattop. Good shot. Equilibrium looks good. Shot 11: Decreased He3 pre-programming to 40 V during the flattop. Good shot. Shot 12: Repeat. Good shot. Shot 13: Raised He3 pre-programming to 50 V. Good shot. Shot 14: Reduced pre-programming on A (K) side H gas from 18.9 to 17 V during the flattop. Good shot. Shot 15: Reduced pre-programming on A (K) side H gas from 17 to 15 V. Reduced pre-programming on B side upper (He3) to 44 V. Good shot. Shot 16: Reduced pre-programming on A (K) side H gas from 15 to 12 V. Turned off density feedback on the He3 gas so that it is only on H now. He3 gas valve voltage set to 52 V. Fizzle. Shot 17: Reduced Br offset by 0.5 mT to 5.9 mT. FSP injected at 1.04 sec. Good shot. Shot 18: He3 reduced to 42 V. H pre-programming shut off at 0.5 sec. Good shot. Good heating, but RF poorly tuned to lower density. Shot 19: Repeat to tune the RF. Power glitch caused a puff of air to enter the machine as well as some other electrical problems. Fizzle. Shot 20: Repeat. Fizzle. Shot 21: Reduced pre-puff by 3 msec to 14 msec. Fizzle. EFC problems. Shot 22: EFC test shot. Start time set to -0.005 sec. EFC looks O.K. Shot 23: Fizzle detector set to 0.5 sec. EFC test. |
| Session Leader Comments |
| Physics Operator Comments | |||
| Dec 14 1995 08:42:00:740AM | Joseph Snipes | Setup:
Discharge clean in hydrogen. Enable A side with hydrogen at 20 psi and B side upper with He3 at 20 psi. Setup as on shot 950608017 except that EF1 L and U limits should be [-7.5,5] and EF2 L and U limits should be 5.5. TF set to a flattop of 180 kA giving 6.45 T flattop. The run will start at 0.8 MA, 6.45 T, and nl04 = 9 x 10^19 m^-2. Then, we will perform a current scan from 0.6 MA to 1 MA, varying the He3 concentration to get the best ICRF heating. The ICRF will be modulated to look at the heating. | |
| Dec 14 1995 09:15:44:610AM | 951214001 | Joseph Snipes | Shot 1 : Copied shot 950608017 into segment 2 and shot 951212015 into segment
1. Extended pre-puff to 19 msec flattop since hydrogen should need higher pressure to breakdown than deuterium. He3 off for this shot. Starting at 0.8 MA, 6.45 T. Decent shot. Hard x rays 0.639 Roentgen. I forgot to enable B top for the pre-puff. There appears to be a H leak since the machine was at 6 x 10^-6 Torr before the shot and at 1 x 10^-5 long after the shot. |
| Dec 14 1995 11:19:28:150AM | 951214002 | Joseph Snipes | Shot 2 : Enabled B top in H at 5 psi and B side upper in He3 at 20 psi. Put
a He3 puff at 90 V from 0.5 to 0.55 sec. Fizzle. |
| Dec 14 1995 11:21:10:360AM | 951214003 | Joseph Snipes | Shot 3 : Reduced pre-puff to 17 msec flattop. Good shot. More gas
problems. Opening ballast on roughing pump to try to improve the pumping. |
| Dec 14 1995 11:37:00:980AM | 951214004 | Joseph Snipes | Shot 4 : He3 puff set to 90 V from 0.6 to 0.7 sec. RF moved to 0.8 sec.
Turned off density feedback from 0.5 sec. Turned off pre-programmed H gas after 0.5 sec. Good shot. |
| Dec 14 1995 11:37:49:390AM | 951214005 | Joseph Snipes | Shot 5 : Reduced pre-puff to 15 msec. Copied gas pre-programming for A (K)
side (H) and B side upper (He3) from shot 950608017 and turned the density feedback on again from 0.5 to 1.8 sec. Good shot. |
| Dec 14 1995 12:01:55:590PM | 951214006 | Joseph Snipes | Shot 6 : Turned off pre-programmed density after 1 sec. RF timing moved to
0.65 sec. Hard x rays early and throughout the shot 0.9 Roentgen. |
| Dec 14 1995 12:07:22:820PM | 951214007 | Joseph Snipes | Shot 7 : Raised pre-programmed He3 puffing from 32 V to 55 V throughout the
flattop. Increased pre-puff to 17 msec. Raised early gas between 0.01 and 0.04 sec. Disrupted at 0.6 sec. Appears that a piece of Moly fell into the plasma. |
| Dec 14 1995 12:51:02:840PM | 951214008 | Joseph Snipes | Shot 8 : Repeat. Good shot.
|
| Dec 14 1995 12:51:27:330PM | 951214009 | Joseph Snipes | Shot 9 : Raised He3 pre-programming to 65 V throughout the flattop. Good
shot. Disrupted at 1.38 sec. |
| Dec 14 1995 12:51:45:080PM | 951214010 | Joseph Snipes | Shot 10: Decreased ZCUR from -1.5 to -2 cm. Decreased ZXL by 1 cm to -1.8
cm. Reduced ZXU from 4 cm down to 2 cm and ramped it to -2 cm by 1.8 sec during the rampdown. Decreased He3 pre-programming to 45 V during the flattop. Good shot. |
| Dec 14 1995 01:35:53:030PM | 951214011 | Joseph Snipes | Shot 11: Decreased He3 pre-programming to 40 V during the flattop.
Good shot. |
| Dec 14 1995 01:36:10:080PM | 951214012 | Joseph Snipes | Shot 12: Repeat. Good shot.
|
| Dec 14 1995 02:22:32:430PM | 951214013 | Joseph Snipes | Shot 13: Raised He3 pre-programming to 50 V.
Good shot. |
| Dec 14 1995 02:23:16:700PM | 951214014 | Joseph Snipes | Shot 14: Reduced pre-programming on A (K) side H gas from 18.9 to 17 V
during the flattop. Good shot. |
| Dec 14 1995 02:25:08:350PM | 951214015 | Joseph Snipes | Shot 15: Reduced pre-programming on A (K) side H gas from 17 to 15 V.
Reduced pre-programming on B side upper (He3) to 44 V. Good shot. |
| Dec 14 1995 02:36:23:030PM | 951214015 | Joseph Snipes | Shot 15: Reduced pre-programming on A (K) side H gas from 17 to 15 V.
Reduced pre-programming on B side upper (He3) to 44 V. Good shot. |
| Dec 14 1995 03:05:47:410PM | 951214016 | Joseph Snipes | Shot 16: Reduced pre-programming on A (K) side H gas from 15 to 12 V.
Turned off density feedback on the He3 gas so that it is only on H now. He3 gas valve voltage set to 52 V. Fizzle. |
| Dec 14 1995 03:12:00:820PM | 951214017 | Joseph Snipes | Shot 17: Reduced Br offset by 0.5 mT to 5.9 mT. FSP injected at 1.04 sec.
Good shot. |
| Dec 14 1995 03:39:55:360PM | 951214018 | Joseph Snipes | Shot 18: He3 reduced to 42 V. H pre-programming shut off at 0.5 sec.
Good shot. Good heating, but RF poorly tuned to lower density. |
| Dec 14 1995 05:24:24:820PM | 951214019 | Joseph Snipes | Shot 19: Repeat to tune the RF. Power glitch caused a puff of air to enter
the machine as well as some other electrical problems. Fizzle. |
| Dec 14 1995 05:25:01:640PM | 951214020 | Joseph Snipes | Shot 20: Repeat. Fizzle.
|
| Dec 14 1995 05:25:22:790PM | 951214021 | Joseph Snipes | Shot 21: Reduced pre-puff by 3 msec to 14 msec. Fizzle. EFC problems.
|
| Dec 14 1995 05:27:13:150PM | 951214022 | Joseph Snipes | Shot 22: EFC test shot. EFC looks O.K.
|
| Dec 14 1995 05:30:02:690PM | 951214023 | Joseph Snipes | Shot 23: Fizzle detector set to 0.5 sec. EFC test. EFC looks O.K.
|
| Dec 14 1995 05:34:32:610PM | 951214023 | Joseph Snipes | At the beginning of the run, there were problems with the turbo pumps not
pumping. So, we stopped and replaced the roughing pump behind the turbo pumps. That helped some, but the neutral pressures were always above 2.5 x 10^-6 Torr and often well above that. Once we got going again at nearly 11:00 am, we got a number of good shots with RF modulation and by adjusting the He3/H ratio some mode conversion heating was observed. Later we had some cooling problems that slowed down the shot rate considerably. Then, just as we were running shot 951214019, there was a power glitch that shut off local power including the room lights. The computers stayed on, but the power supplies were left in an unusual state and somehow air was puffed into the machine. After resetting a number of things including the cryo pump, the cooling system, gate valves, etc,, we tried again to get plasma. |
| Dec 14 1995 05:34:52:580PM | 951214023 | Joseph Snipes | Shot 19 was retaken and it fizzled. Then, we tried again and it fizzled.
Wolfe then noticed that the EFC supply was not working. We fired shot 21 and it also fizzled and EFC failed again. We then stopped to investigate the EFC problem. A couple of EFC tests showed that EFC seems to be O.K. Scorecard: 23 shots, 16 plasmas, 5 fizzles, 2 test shots |
| Engineering Operator Comments | ||||
| Shot | Time | Type | Status | Comment |
| 1 | 08:51:01:330AM | Plasma | Ok | |
| 2 | 10:47:57:090AM | Plasma | Ok | |
| 3 | 10:56:22:310AM | Plasma | Ok | |
| 4 | 11:20:27:140AM | Plasma | Ok | |
| 5 | 11:35:39:970AM | Plasma | Ok | |
| 6 | 11:48:07:850AM | Plasma | Ok | |
| 7 | 12:00:46:560PM | Plasma | Ok | oh2 bypass self fire |
| 8 | 12:09:50:430PM | Plasma | Ok | |
| 9 | 12:24:14:470PM | Plasma | Ok | |
| 10 | 12:48:57:930PM | Plasma | Ok | no faults |
| 11 | 01:15:39:210PM | Plasma | Ok | |
| 12 | 01:27:22:160PM | Plasma | Ok | |
| 13 | 01:54:16:430PM | Plasma | Ok | |
| 14 | 02:06:11:200PM | Plasma | Ok | |
| 15 | 02:23:01:400PM | Plasma | Ok | |
| 16 | 02:56:43:980PM | Plasma | Ok | |
| 17 | 03:07:30:690PM | Plasma | Ok | |
| 18 | 03:26:51:880PM | Plasma | Ok | |
| 19 | 03:42:07:610PM | Plasma | Ok | |
| 20 | 04:26:25:550PM | Plasma | Ok | |
| 21 | 04:41:39:850PM | Plasma | Ok | |
| 22 | 05:21:14:040PM | Plasma | Ok | |
| 23 | 05:28:27:290PM | Plasma | Ok | |