| Miniproposals | ||||||||||
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| Operators | |
| Session leader(s): | Liang Lin |
| Physics operator(s): | Robert Granetz |
| Engineering operator(s): | Sam Pierson,Bill Byford,Gary Dekow |
| Engineering Operator Run Comment |
| automatically entered by signon - please replace with real comment |
| Session Leader Plans |
| Entered: Sep 16 2009 04:53:56:433PM |
| Author: Liang Lin |
| Subject: Further Investigation of Turbulence and Transport in Low Density Ohmic Plasmas to Resolve the Mystery of Electron Transport
This run is the first phase of MP 571. The purpose of this experiment is to explore the role played by the current profile in the low-density ohmic plasmas where the electron transport dominates. The experiments will be carried out at three different toroidal magnetic fields: B = 5.2, 3.9, and 2.6 T, where Ip is changed accordingly to keep qa constant: 0.8, 0.6, and 0.4 MA, respectively. The field variation at the same q should unambiguous reveal the role played by the current and possibly its profile. At each magnetic field and corresponding plasma current, the line-averaged electron density will be scanned from 1.0 to 0.3 (possibly 0.2) �?10^20 m^-3 to cover both the linear ohmic region and the transition from the linear ohmic to the saturated ohmic region. The electron density and temperature profiles will be carefully measured by the improved Thomson scattering system, and the turbulence level will be monitored by PCI. |
| Physics Operators Plans |
| Entered: Sep 16 2009 04:52:39:890PM |
| Author: Robert Granetz |
Engineering setup for Thursday 2009/09/17
MP571 - Further investication of turbulence and transport in low density
ohmic plasmas to resolve the mystery of electron transport
Session leaders: L. Lin
Physics operator: R. Granetz
Overnight boronization, usual recipe, except that we will start one hour
late (~18:00), and will not do the D2 ECDC in the morning. (We will do the
usual 3 hours of He ECDC.)
Run will start at 09:00 and end at 17:00.
Power systems as on 1090825001 (Bt=5.4T, Ip=0.8 MA)
A-coil configuration: +Dtop -Dbot -Jtop +Jbot; Enabled (standard
configuration)
Gas Setup:
fill B-Top with 6 psi D2 Hybrid enabled (PG4)
fill B-side lower with 1 psi Ar Hybrid DISABLED (PG1)
leave B-side upper as is Hybrid DISABLED (PG2)
fill B-main (C-side) with 40 psi D2 Hybrid enabled (PG3)
leave NINJA as is DISABLED
Enable the following gate valves and shutters, assuming no vacuum problems:
ECE, VUV, Z-bolo
Torvac setup: keep gate valves open during PULSE
Specific diagnostics: PCI, fast magnetics
------------------------------------------------------------------------------
ICRF Setup: no, ohmic only
LH Setup: no
DNB: fat chance
Cryopump: no
------------------------------------------------------------------------------
Run plan: Load shot 1090825001, including seg 1, but set Btor=5.2 T and
nl_04=0.6e20 m-2. Run a series of shots to scan density
shot-by-shot. Then decrease Btor to 3.9 T and Ip to 0.6 MA
(keeps q constant) and run another density scan series. Finally
decrease Btor to 2.6 T and Ip to 0.4 MA (again keeping q
constant) and run a final density scan series. NOTE: for the
low-field shots, I may try using Ian's low-field startup in seg 1
(1090710003 seg 1, with the corresponding engineering setup).
|
| Session Leader Summaries |
| Entered: Sep 17 2009 06:32:29:427PM |
| Author: Liang Lin |
| MP5571 - Further investication of turbulence and transport in low density
ohmic plasmas to resolve the mystery of electron transport A computer problem caused us to lose three hours of today's runs time. Furthermore, it is quite difficult to reduce the density to reach the linear ohmic regime mostly due to the residual gas on the wall. Within the limited time, two density scans have been performed at Bt = 5.2 T ( Ip = 0.8 MA) and Bt = 2.6 T (Ip = 0.4 MA): At Bt = 2.6 T and Ip = 0.4 MA, the line-averaged density is scanned from 0.3x10^20 m^-3 to 0.8x10^20 m^-3, where initial analysis shows that both linear and saturated ohmic regime are covered. At Bt = 5.2 T and Ip = 0.8 MA, the lowest line-averaged density is 0.6x10^20 m^-3. This corresponds to the transition from the linear ohmic regime to the saturated ohmic regime, where the electrons and ions are still not fully decoupled to separate the electron thermal outside of the experimental uncertainty. Tomorrow's run will start from obtaining a low-density ohmic plasma at Bt = 5.2 T and Ip = 0.8 MA in the linear ohmic regime. The density scan at Bt = 3.9 and Ip = 0.6 MA is not carried out and will be pursued tomorrow if time is allowed. |
| Physics Operator Summaries |
| Entered: Sep 17 2009 05:18:38:860PM |
| Author: Robert Granetz |
Run summary for Thursday 2009/09/17
MP5571 - Further investication of turbulence and transport in low density
ohmic plasmas to resolve the mystery of electron transport
Session leaders: L. Lin
Physics operator: R. Granetz
Today's run was ohmic only, so nearly all plasmas were full length and
relatively clean. The goal was to do a density scan to very low values,
but this was problematic, perhaps because of the previous night's
boronization. The lowest densities achieved were nl_04=0.4e20 m-2 at 5.2 T
(and 0.8 MA), and nl_04=0.2e20 m-2 at 2.6 T (and 0.4 MA). For the
low-field portion of the run, I first tried using Ian's low-field startup
(seg 1 from 1090710003), but I couldn't get it to go, even though I tried 3
shots with 3 different pre-fill pressures. So the low-field plasmas were
obtained by using a normal startup and then ramping the TF down to 2.6 T
during seg 2.
There was a significant delay (2+ hours) in the late morning due to the
RSView server computer crashing. This was determined to be a hardware
failure of its motherboard, and the computer had to be replaced with a
spare. The first shot after restarting operation was a dud due to the
OH2's not turning on, which probably was a consequence of the RSView
crash.
Scorecard: 23 plasmas
1 duds
3 fizzles (one because cryopump regenerated just before shot)
0 power supply tests
0 no-power MDS shot cycles
--------------
Total: 27 shot cycles
|
| Session Leader Comments | |||
| Sep 17 2009 11:01:59:977AM | 1090917002 | Liang Lin | Shot 2: Nice start
nl_04 = 0.75 10^20/m^3. nebar = 1.20 10^20/m^3 tau_kin = 42.04 msec |
| Sep 17 2009 11:01:34:523AM | 1090917003 | Liang Lin | Shot 3: Nice shot.
nebar = 1.2 10^20/m^3 tau_kin = 38.5 msec Repeat to deplete the walls. |
| Sep 17 2009 11:01:13:257AM | 1090917004 | Liang Lin | Shot 4:
nebar = 1.1 10^20/m^3 tau_kin = 39.9 msec Repeat. |
| Sep 17 2009 11:00:41:867AM | 1090917005 | Liang Lin | Shot 5: Nice shot.
nebar = 1.0 10^20/m^3 tau_kin = 43.17 msec Next: low the plasma vertically by 1 cm for a better spatial resolution of TS |
| Sep 17 2009 11:00:16:320AM | 1090917006 | Liang Lin | Shot 6: Nice shot.
nebar = 1.1 10^20/m^3 tau_kin = 41.4 msec TS spatial coverage is improved after vertically lowering the plasma by 1 cm, but the density increased by ~10% than the previous shot. Next: repeat with the NINJA D2 closed. |
| Sep 17 2009 10:59:53:697AM | 1090917007 | Liang Lin | Shot 7: Nice shot.
nebar = 1.03 10^20/m^3 tau_kin = 38.6 msec The nl_04 remains around 0.6 and higher than the programmed 0.45. Next: repeat. |
| Sep 17 2009 02:17:16:133PM | 1090917010 | Liang Lin | shot 10:
nebar = 0.78 10^20/m^3 tau_kin = 42.3 msec Next shot: repeat to see if density is lowered. |
| Sep 17 2009 02:02:56:163PM | 1090917011 | Liang Lin | shot 11:
nebar = 0.64 10^20/m^3 tau_kin = 40.85 msec Next shot: repeat to see if density continues decreasing. |
| Sep 17 2009 02:16:49:040PM | 1090917012 | Liang Lin | Shot 12:
tau = 36.4 msec The confinement time decreases ~ 4 msec and it starts getting into the linear ohmic regime. Next shot: repeat to see if density continues decreasing. |
| Sep 17 2009 02:09:55:727PM | 1090917013 | Liang Lin | Shot 13: Nice Plasma
nebar = 0.58 10^20/m^3 tau = 37.9 msec The nl_04 did not drop. Next shot: repeat. |
| Sep 17 2009 02:27:10:570PM | 1090917014 | Liang Lin | Shot 14:
nebar = 0.58 tau = 35.0 The nl_04 remains around 0.4 and does not decrease. Next shot: repeat. |
| Sep 17 2009 02:39:49:100PM | 1090917015 | Liang Lin | Shot 15:
nebar = 0.6 tau = 37. The nl_04 remains around 0.4 and does not decrease. Next shot: switch Bt from 5.2 to 2.6 T and Ip from 0.8 MA to 0.4 MA. |
| Sep 17 2009 03:48:31:407PM | 1090917020 | Liang Lin | Shot 20:
Bt = 2.6 T; Ip = 0.4 MA; nebar = 0.3 10^20/m^3 tau = 24. msec Next shot: raise the nl_04 to 0.3 10^20/m^2 |
| Sep 17 2009 04:00:12:830PM | 1090917021 | Liang Lin | Shot 21:
nebar = 0.45 10^20/m^3 tau = 28.7 msec Next shot: raise the nl_04 to 0.4 10^20/m^2 |
| Sep 17 2009 04:14:03:207PM | 1090917022 | Liang Lin | Shot 22:
nebar = 0.65 10^20/m^3 tau = 27.8 msec Next shot: raise nl_04 to 0.5 10^20/m^2 |
| Sep 17 2009 04:34:58:050PM | 1090917023 | Liang Lin | Shot: 23
nebar = 0.81 10^20/m^3 tau = 25.8 msec Next shot: Keep the same magnetic field and the current and lower nl_04 to the minimum. |
| Sep 17 2009 04:42:06:720PM | 1090917024 | Liang Lin | Shot: 24
nebar = 0.61 10^20/m^3 tau = 29.6 msec Next: Repeat |
| Sep 17 2009 04:51:12:673PM | 1090917025 | Liang Lin | Shot: 25
nebar = 0.59 10^20/m^3 tau = 27.87 msec Next: change Bt to 5.2 T and Ip to 0.8 MA and lower nl_04 to the minimum. |
| Sep 17 2009 05:04:37:283PM | 1090917026 | Liang Lin | Shot 26:
nebar = 0.67 10^20/m^3 tau = 41.4 msec Next shot will be a repeat and will be the last shot of today. Thank you all! |
| Sep 17 2009 05:17:57:813PM | 1090917027 | Liang Lin | Shot 27:
nebar = 0.55 10^20/m^3 tau = 35 msec The density did not drop as we expected. Tomorrow's run will start from here to obtain a low-density shot (nebar ~0.35 10^20/m^3). |
| Physics Operator Comments | |||
| Sep 17 2009 09:16:20:663AM | 1090917001 | Robert Granetz |
Shot 01 -- Plasma, but something very weird happened at the segment switch. No magnetics errors of
consequence. All DPCS programming seems to be correct. It might just be a large marfe.
Gas is okay.
This morning we only did He ECDC after the overnight boronization, no D2 ECDC,
because we want to run low densities today. Maybe that had something to do
with this weird shot.
Next shot: reduce PG3 programming in seg 1
|
| Sep 17 2009 09:20:56:333AM | 1090917002 | Robert Granetz | Shot 02 -- Plasma, full length. 0.8 MA, 5.2 T, 0.75e20 m-2. Shape parameters are all acceptable. Next shot: decrease nl_04 to 0.45e20 m-2 |
| Sep 17 2009 09:33:33:960AM | 1090917003 | Robert Granetz |
Shot 03 -- Plasma, full length. 0.8 MA, 5.2 T, 0.7e20 m-2. Gas fueling stayed off, so we're just
fueling off the walls. We'll have to run a few more shots to deplete the walls.
Next shot: repeat DPCS changes; 50 ms argon puff will be enabled at t=0.30 s; NINJA is puffing D2
at t=1.35 s
|
| Sep 17 2009 09:44:40:883AM | 1090917004 | Robert Granetz |
Shot 04 -- Plasma, full length. 0.8 MA, 5.2 T, 0.65e20 m-2. Density came down, but only slightly. We'll
just have to continue running plasmas to delete the walls. The gas fueling is off for the
entire shot.
Next shot: repeat, no changes
|
| Sep 17 2009 09:59:01:680AM | 1090917005 | Robert Granetz | Shot 05 -- Plasma, full length. 0.8 MA, 5.2 T, 0.6e20 m-2. Next shot: move plasma ZCUR down by 1 cm |
| Sep 17 2009 10:15:15:553AM | 1090917006 | Robert Granetz |
Shot 06 -- Plasma, full length. 0.8 MA, 5.2 T, 0.6e20 m-2. ZCUR did indeed move down by 1 cm. This
was done to optimize TS coverage. The density is still above the programmed value.
Next shot: turn off the NINJA D2 puff for a few shots to see if the density will come down
|
| Sep 17 2009 10:29:34:350AM | 1090917007 | Robert Granetz |
Shot 07 -- Plasma, full length. 0.8 MA, 5.2 T, 0.6e20 m-2.
Next shot: increase CLEARIN a little earlier to get it off the inboard wall and reduce that fueling;
tweak early ZCUR in seg 2 to better match at segment switch
|
| Sep 17 2009 10:55:23:727AM | 1090917008 | Robert Granetz |
Shot 08 -- Shot cycle failed in INIT. All the engineering PLC computers froze. They are not displaying
any PLC outputs. Weird. Call Joe Bosco and Yuri. And Tom and Josh.
Next shot:
|
| Sep 17 2009 12:46:31:257PM | 1090917008 | Robert Granetz | Shot 08 -- Dud, no OH2s. This was the 2nd attempt at shot 08. Next shot: try again; (remember: CLEARIN was increased after shot 7) |
| Sep 17 2009 01:19:36:583PM | 1090917009 | Robert Granetz |
Shot 09 -- Plasma, full length. 0.8 MA, 5.2 T, 0.6e20 m-2. Slightly lower density. The plasma now diverts
around 0.2 s (was 0.3 s). No Thomson data.
Next shot: decrease nl_04 to 0.3e20 m-2; also decrease PG3 puff in seg 1 even more
|
| Sep 17 2009 01:27:07:883PM | 1090917010 | Robert Granetz |
Shot 10 -- Plasma, full length. 0.8 MA, 5.2 T, 0.5e20 m-2. Got lower density, but it's still above the
programmed demand, and the gas valve is remaining off.
Next shot: repeat, no DPCS changes; NINJA will remain off
|
| Sep 17 2009 01:42:41:960PM | 1090917011 | Robert Granetz |
Shot 11 -- Plasma, full length. 0.8 MA, 5.2 T, 0.4e20 m-2. Gas valve is still closed for the
entire shot.
Next shot: decrease nl_04 to 0.2e20 m-2, even though the actual density is not down at the demand yet
|
| Sep 17 2009 01:59:05:507PM | 1090917012 | Robert Granetz |
Shot 12 -- Plasma, full length. 0.8 MA, 5.2 T, 0.4e20 m-2. Might have just barely turned the corner
on the neo-Alcator confinement time scaling
Next shot: no DPCS changes
|
| Sep 17 2009 02:06:54:553PM | 1090917013 | Robert Granetz | Shot 13 -- Plasma, full length. 0.8 MA, 5.2 T, 0.4e20 m-2. Density didn't go down any further on this shot. Next shot: no DPCS changes |
| Sep 17 2009 02:22:29:850PM | 1090917014 | Robert Granetz | Shot 14 -- Plasma, full length. 0.8 MA, 5.2 T, 0.4e20 m-2. Next shot: tweak RCUR to keep outer gap more constant during the latter part of the shot |
| Sep 17 2009 02:39:57:007PM | 1090917015 | Robert Granetz |
Shot 15 -- Plasma, full length. 0.8 MA, 5.2 T, 0.4e20 m-2.
Next shot: Change Btor to 2.6 T and Ip to 0.4 MA. Use Ian's low-field startup in seg 1 (1090710003).
Have the engineers load their setup from that shot as well.
|
| Sep 17 2009 02:55:35:367PM | 1090917016 | Robert Granetz |
Shot 16 -- Fizzle (almost a dud). Fields look good. Ian had a short pre-fill pulse, so the gas pressure
was quite low.
Next shot: increase pre-fill to 24 ms
|
| Sep 17 2009 03:09:33:303PM | 1090917017 | Robert Granetz |
Shot 17 -- Fizzle (almost a dud). Fields are fine, gas pressure is fine.
Next shot: increase pre-fill to 30 ms and try one last time; If this doesn't work, I'll switch back
to a normal startup and let the field rampdown during the shot.
|
| Sep 17 2009 03:21:40:100PM | 1090917018 | Robert Granetz |
Shot 18 -- Fizzle. Pressure was indeed higher. Bail out of this.
Next shot: reload seg 1 with seg 1 of 1090917015; reload engineering setup from that shot as well;
seg 2 is still calling for 2.6 T and 0.4 MA
|
| Sep 17 2009 03:35:38:903PM | 1090917019 | Robert Granetz | Shot 19 -- Plasma, full length. 0.41 MA, 2.75 T, 0.22e20 m-2. Outer gap is pretty constant. Next shot: decrease Itor a bit more to get 2.6 T (68.3 kA) |
| Sep 17 2009 03:46:56:203PM | 1090917020 | Robert Granetz | Shot 20 -- Plasma, full length. 0.4 MA, 2.6 T, 0.2e20 m-2 Next shot: raise nl_04 to 0.3e20 m-2 |
| Sep 17 2009 04:04:49:050PM | 1090917021 | Robert Granetz | Shot 21 -- Plasma, full length. 0.4 MA, 2.6 T, 0.3e20 m-2 Next shot: raise nl_04 to 0.4e20 m-2 |
| Sep 17 2009 04:12:11:190PM | 1090917022 | Robert Granetz | Shot 22 -- Plasma, full length. 0.4 MA, 2.6 T, 0.4e20 m-2 Next shot: raise nl_04 to 0.5e20 m-2 |
| Sep 17 2009 04:27:20:830PM | 1090917023 | Robert Granetz | Shot 23 -- Plasma, full length. 0.4 MA, 2.6 T, 0.5e20 m-2 Next shot: decrease nl_04 to 0.1e20 m-2 (i.e. get the minimum density possible) |
| Sep 17 2009 04:41:27:910PM | 1090917024 | Robert Granetz |
Shot 24 -- Plasma, full length. 0.4 MA, 2.6 T, 0.4e20 m-2. Density didn't come down as much as we
we hoping.
Next shot: repeat, no DPCS changes (nl_04 is programmed at 0.1e20 m-2)
|
| Sep 17 2009 04:51:19:690PM | 1090917025 | Robert Granetz | Shot 25 -- Plasma, full length. 0.4 MA, 2.6 T, 0.3e20 m-2 Next shot: go back to 0.8 MA, 5.2 T, but leave nl_04 programmed at 0.1e20 m-2 |
| Sep 17 2009 05:03:13:880PM | 1090917026 | Robert Granetz | Shot 26 -- Plasma, full length. 0.8 MA, 5.2 T, 0.4e20 m-2. Density was not lower than shot 15. Next shot: repeat, no changes; see if the density drops any |
| Sep 17 2009 05:14:16:770PM | 1090917027 | Robert Granetz | Shot 27 -- Plasma, full length. 0.8 MA, 5.2 T, 0.37e20 m-2. So the density didn't drop significantly. End of run |
| Engineering Operator Comments | ||||
| Shot | Time | Type | Status | Comment |
| 1 | 08:56:00:400AM | Plasma | Ok | |
| 2 | 09:12:08:757AM | Plasma | Ok | |
| 3 | 09:26:03:663AM | Plasma | Ok | |
| 4 | 09:39:12:227AM | Plasma | Ok | |
| 5 | 09:52:00:117AM | Plasma | Ok | |
| 6 | 10:04:50:710AM | Plasma | Ok | |
| 7 | 10:19:19:430AM | Plasma | Ok | |
| 8 | 10:36:51:210AM | Plasma | Bad | No OH2's |
| 9 | 01:08:04:710PM | Plasma | Ok | |
| 10 | 01:21:08:303PM | Plasma | Ok | |
| 11 | 01:34:06:883PM | Plasma | Ok | |
| 12 | 01:48:30:380PM | Plasma | Ok | |
| 13 | 02:03:01:617PM | Plasma | Ok | |
| 14 | 02:18:41:803PM | Plasma | Ok | |
| 15 | 02:34:38:790PM | Plasma | Ok | |
| 16 | 02:49:28:210PM | Plasma | Ok | |
| 17 | 03:02:15:837PM | Plasma | Ok | |
| 18 | 03:15:22:163PM | Plasma | Ok | |
| 19 | 03:28:01:587PM | Plasma | Ok | |
| 20 | 03:40:47:897PM | Plasma | Ok | |
| 21 | 03:53:28:410PM | Plasma | Ok | |
| 22 | 04:06:35:097PM | Plasma | Ok | |
| 23 | 04:20:37:800PM | Plasma | Ok | |
| 24 | 04:33:13:177PM | Plasma | Ok | |
| 25 | 04:45:58:457PM | Plasma | Ok | |
| 26 | 04:58:47:143PM | Plasma | Ok | |
| 27 | 05:11:20:580PM | Plasma | Ok | |
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