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| Operators | |
| Session leader(s): | Joseph Snipes,Jerry Hughes,Brian Labombard |
| Physics operator(s): | Robert Granetz |
| Engineering operator(s): | Sam Pierson,Bill Cochran |
| Engineering Operator Run Comment |
| am: MP529 Btor dependence of the L-H transition at low ne in ohmic plasm |
| Session Leader Plans |
| Entered: Mar 10 2008 12:46:01:060PM |
| Author: Steve Scott |
| MSE beam-into-gas calibrations MP491 A. single-shot reproducibility evaluation * three identical shots. - one shot at beginning of day - one shot at the end of the morning run for MP491 - Last shot of the day. * conditions: beam-into-gas with fields, no plasma. - TF and gas programming from shot 1070831006 - EF3 and EF4 wveforms from: 1. Take both from 1070529008 (EF3=9.5, EF4=0) 2. OR take both EF3 and EF4 from 1070831033 and then set EF4=0. - Make sure that EF4 is """"""""open"""""""" so we don't induce currents in it. - Note: these conditions are BT=constant, EF3=constant, EF4=0 = constant. - DNB: will be operated in modulated mode to get high current and hopefully a current that remains relatively constant throughout the pulse. Start at 0.2 sec, end at 1.7 sec. Proposed on/off timing is on/off = 80/30 ms, but this will be adjusted as needed to get a nice waveform. B. Single-shot full MSE calibration * TF, EF3 and EF4 conditions taken from 1070831006. * 2 shots. these will have the same TF, EF3 and EF4 waveforms but different torus pressures. * first shot: torus pressure = constant = 0.5 mTorr * second shot: torus pressure = 1.5 mTorr (See shots 1070529003 / 004 for an example of how to increase the torus pressure from 0.5 to about 1.3 mTorr). * close torus values to improve constancy of torus pressure * large ramps on EF3 and EF4. * 6 PSI on torus gas plenum. Deuterium gas. C. Single-shot torus pressure scan * 2 shots, with same TF but different EF --> to give different pitch angle. * 1st shot: conditions = 1070529007, including gas puffing, TF, EF3, EF4. * 2nd shot: conditions = 1070529010, including gas puffing, TF, EF3, EF4. * In both shots: BT = constant, EF3 and EF4 = constant. Ramp the torus pressure. * DNB modulated, probably at 80/30 ms = on/off. start 0.05, end 1.5 sec. D. Verify MSE filter temperature * 2 shots, identical. * start with conditions from shot 1070615027. Then modify as indicated in file fields_and_mflux_1070615027.pdf. * These waveforms are intended to provide constant pitch angle as the BT is ramped from 5.0 --> 6.2 Tesla. * MSE filter temperatures will be optimized for 5.4 Tesla. * Gas puffing taken from shot A above, adjusted as necessary to get about 0.5 mTorr, and constant torus pressure versus time. * MSE will evaluate polarization fraction versus time. * DNB: modulated as described above. Start time = 0.05 sec. end time = 1.5 sec. |
| Entered: Mar 10 2008 03:09:50:567PM |
| Author: Joseph Snipes |
| Session Leader Run Plan for Tuesday 1080311
MP529 Toroidal field dependence of the L-H transition at low density in Ohmic and ICRF heated plasmas - Part I Ohmic plasmas This is an Ohmic H-mode run where we will ramp the toroidal field down from 5.4 T at breakdown to a minimum of 2.2 T and vary the electron density to look for a low density limit to obtaining H-modes. The plasma current may also be varied somewhat to change the Ohmic input power, but we want to avoid low q disruptions as much as possible. We will begin with shot 1080305025 except that we will reduce the minimum toroidal field to 2.2 T and reduce the plasma current to 0.6 MA. Assuming H-mode is achieved, we will then reduce the density in small steps and map out the minimum density at which H-mode can be achieved. We may increase the plasma current somewhat to increase the Ohmic input power if necessary, but we probably cannot go much higher than 0.7 MA and also avoid low q disruptions. We would also like to monitor edge plasma flows and core plasma rotation, measure the edge and core density and temperature profiles, measure the radiated power profile and visible Bremsstrahlung profile for Zeff, and measure fluctuations with the magnetics, PCI, and reflectometry. |
| Entered: Mar 10 2008 06:02:38:457PM |
| Author: Jerry Hughes |
| MP296. Cross-calibrate TS against ECE cutoffs.
Ohmic plasmas, ~800kA, ~4T GPC should be configured for 4T operation. This run is in two parts: 1. Load any recent 800kA shot with a standard LSN equilibrium. (I would give you one, but I can't see any 2008 data.) Adjust Bt to be 3.9T in flattop. Make initial density demand nl04=1.2e20. Then ramp nl04 program from nl04=1.2e20 to 2.0e20 from 0.6s to 1.0s. 2. Repeat, adjusting Bt in steps of 0.1T, and possibly changing the density program, until session leader is satisfied. Pretty simple, huh? |
| Physics Operators Plans |
| Entered: Mar 10 2008 11:09:00:380PM |
| Author: Robert Granetz |
Engineering setup for Tuesday 11 Mar 2008
am: MP529 Btor dependence of the L-H transition at low ne in ohmic plasmas
pm: TS calibrations (4 shots)
pm: MP491 MSE calibrations (if LHe is available in time)
Session leader: Snipes/Hughes/Scott
Physics operator: Granetz
Normal overnight ECDC in D2 and 60 C bake.
Run will start at 09:00 and end at 17:00.
Power systems as on 1080305025.
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
Specific diagnostics: Thomson, GPC (cross-calibration), MSE, HIREXes
-------------------------------------------------------------------------------
ICRF Setup: not needed
LH Setup: not needed
DNB: yes, for MP491
Cryopump: not needed
-------------------------------------------------------------------------------
Run plan:
MP529 -- Set Btor to 2.2 T after breakdown; set Ip at 0.6 MA; nl_04=4e19 m-2.
Decrease density shot-to-shot until H-mode no longer occurs
during the Btor ramp.
TS calibrations: ramp ne up during shot to reach ECE cutoff.
Cross-calibrate GPC and TS.
MSE calibrations: beam-into-gas with fields. We will only do this run if
LHe becomes available in time.
|
| Session Leader Summaries |
| Entered: Mar 11 2008 02:06:28:963PM |
| Author: Joseph Snipes |
| It was a very good run with 18 good shots out of 19 attempts. We were able to get Ohmic H-modes down to as low a density as the machine could go before getting runaways, which was down to nel04 = 0.2 x 10^20 m^-2 or nebar = 0.34 x 10^20 m^-3.
Attempts to go to lower densities did not get H-mode. This is not that much larger than the low density limit obtained at similar toroidal fields on DIII-D, JET, JT-60U, and ASDEX Upgrade, which were about nebar = 0.25 x 10^20 m^-3. To get the H-mode at the lowest density in C-Mod required 2.2 times the old H-mode threshold scaling: Pth = 1.42 nebar^0.58 BT^0.82 a^0.81 R^1.0. This is much lower than the low density limit at 5.4 T, which is more like nebar = 0.8 - 1.0 x 10^20 m^-3. This suggests that ITER could have a similarly high low density limit at 5.3 T since the low density limit does not appear to change substantially with machine size. So, ITER may have difficulty getting H-mode at the L-mode target density presently envisioned for the base scenario, nebar = 5 x 10^19 m^-3, unless the input power is substantially larger than the threshold scaling. |
| Entered: Mar 12 2008 09:09:10:317AM |
| Author: Jerry Hughes |
| MP296: Calibration of Thomson density against ECE cutoffs.
(Shots 20--26) This was a good ~1/4 run. In 7 attempts, we got 5 ohmic plasmas at 800kA with density ramps to disruption in all cases. Three fields were run (4.0+/-0.1T), with the GPC coverage optimized for 4T. In all shots ECE was completely cut off on the LFS by 1.3s. Almost 60 total cutoffs were obtained, allowing density calibration coefficients to be calculated for the core TS, and adjusted in the case of the edge TS. These shots will be analyzed carefully and supplemented with gas scattering calibration data taken on March 2. Meanwhile, control room analysis showed that the corrections to the existing calibrations are ~1, with some densities overestimated and others underestimated. The central density is being underreported by several percent, while a number of channels at larger r/a are being overreported. When the ongoing restoration of 2008 data is completed, these results will be used to back-calibrate some old shots. (Note that this calibration is for YAG1 only, since YAG2 is in need of repair. YAG2 calibrations will be determined by comparing gas scattering data taken with both lasers.) Summary of correction factors derived from shots 20,22,24--26: GPC, YAG1 Polychromator 6: 1.08973 +/- 0.0872417 Polychromator 5: 0.958995 +/- 0.0563128 Polychromator 9: 1.25188 +/- 0.0817014 Polychromator 1: 1.02906 +/- 0.0817457 Polychromator 11: 0.878957 +/- 0.0692032 Polychromator 4: 0.944308 +/- 0.0614470 Polychromator 3: 0.995157 +/- 0.0583481 Polychromator 2: 1.00443 +/- 0.0787527 Polychromator 7: 0.716466 +/- 0.0469350 Polychromator 8: 0.962612 +/- 0.0637591 Polychromator 15: 1.54223 +/- 0.102410 Polychromator 13: 1.51114 +/- 0.174921 GPC2, YAG1 Polychromator 6: 1.06321 +/- 0.0238567 Polychromator 5: 0.947644 +/- 0.0195676 Polychromator 9: 1.24880 +/- 0.0323237 Polychromator 1: 1.04010 +/- 0.0494762 Polychromator 11: 0.864306 +/- 0.0240111 Polychromator 4: 0.934159 +/- 0.0177258 Polychromator 3: 1.00496 +/- 0.0182039 Polychromator 2: 1.01319 +/- 0.0336075 Polychromator 7: 0.781141 +/- 0.0279718 Polychromator 8: N/A Polychromator 15: N/A Polychromator 13: 1.00757 +/- 0.498827 Decent results for 11 innermost core channels. The channel near the LCFS is not so accurately calibrated. |
| Physics Operator Summaries |
| Entered: Mar 11 2008 05:02:19:120PM |
| Author: Robert Granetz |
Run summary for Tuesday 11 Mar 2008
am: MP529 Btor dependence of the L-H transition at low ne in ohmic plasmas
pm: TS calibrations (4 shots)
pm: CANCELLED: MP491 MSE calibrations (if LHe is available in time)
pm: MP493 Ohmic L-H Threshold Experiments
Session leader: J. Snipes; J. Hughes; B. LaBombard
Physics operator: R. Granetz
The first half-day run (MP529) went extremely well, with the machine
achieving very low densities of <2e19 m-2 at Btor=2.2 T and Ip=0.45-0.60
MA. A reproducible low density H-mode threshold was determined.
The Thomson calibration also went well, although each plasma shot resulted
in a high-density disruption, which invariably led to an alternating
pattern of a plasma shot followed by a fizzle.
Finally, we tried to get a head start on Brian's MP493 which is scheduled
for this Thursday. This was impeded by the inability to recall data from
recent runs, since it required us to start developing shots from scratch.
But we managed to get an upper null plasma that didn't disrupt
(1080311030), and this will be a reasonable starting shot for Thursday.
Scorecard: 27 plasmas
0 duds
3 fizzles
0 power supply tests
1 no-power MDS shot cycles
--------------
Total: 31 shot cycles
|
| Session Leader Comments | |||
| Mar 11 2008 09:15:40:400AM | 1080311001 | Joseph Snipes | Shot 1: Good shot. H-mode at 1.24 s at Bt = 2.38 T and 0.6 MA and nl04 = 0.4 x 10^20 m^-2 corresponding to nebar = 0.7 x 10^20 m^-3. |
| Mar 11 2008 09:28:07:900AM | 1080311002 | Joseph Snipes | Shot 2: Reduce TF to 2.2 T minimum. Got H-mode at 1.03 s at 2.4 T and nl04 = 0.36 x 10^20 m^-2 corresponding to nebar = 0.68 x 10^20 m^-3. |
| Mar 11 2008 09:32:44:947AM | 1080311003 | Joseph Snipes | Shot 3: Reduce Ip to 0.55 MA. Good shot. Got H-mode at 1.19 s at 2.23 T and nl04 = 0.36 x 10^20 m^-2 corresponding to nebar = 0.71 x 10^20 m^-3. |
| Mar 11 2008 09:48:13:663AM | 1080311004 | Joseph Snipes | Shot 4: Reduce Ip to 0.5 MA. Good shot. Got H-mode at 1.17 s at 2.25 T and nl04 = 0.35 x 10^20 m^-2 corresponding to nebar = 0.71 x 10^20 m^-3. |
| Mar 11 2008 09:57:16:837AM | 1080311005 | Joseph Snipes | Shot 5: Reduce Ip to 0.45 MA. Good shot. Got H-mode at 1.47 s at 2.2 T and nl04 = 0.35 x 10^20 m^-2 corresponding to nebar = 0.6 x 10^20 m^-3. |
| Mar 11 2008 10:11:41:853AM | 1080311006 | Joseph Snipes | Shot 6: Reduce nl04 to 0.35 x 10^20 m^-2. Good shot. Got H-mode at 1.4 s at 2.2 T and nl04 = 0.32 x 10^20 m^-2 corresponding to nebar = 0.55 x 10^20 m^-3. |
| Mar 11 2008 10:24:51:010AM | 1080311007 | Joseph Snipes | Shot 7: Reduce nl04 to 0.3 x 10^20 m^-2. Good shot. Got H-mode at 1.48 s at 2.2 T and nl04 = 0.3 x 10^20 m^-2 corresponding to nebar = 0.52 x 10^20 m^-3. |
| Mar 11 2008 11:05:33:930AM | 1080311008 | Joseph Snipes | Shot 8: Reduce nl04 to 0.25 x 10^20 m^-2. Good shot. Got H-mode at 1.51 s at 2.2 T and nl04 = 0.25 x 10^20 m^-2 corresponding to nebar = 0.44 x 10^20 m^-3. |
| Mar 11 2008 11:29:22:167AM | 1080311009 | Joseph Snipes | Shot 9: Reduce nl04 to 0.2 x 10^20 m^-2. Added 75 ms of argon for HIREX. Got hard x rays from 0.4 s because the density dips too low as the plasma goes diverted. No H-mode. |
| Mar 11 2008 12:03:43:103PM | 1080311010 | Joseph Snipes | Shot 10: Try increasing the density early and ramping down to 0.2 x 10^20 m^-2.
Still got hard x rays. No H-mode. |
| Mar 11 2008 12:03:01:057PM | 1080311012 | Joseph Snipes | Shot 12: Try increasing the density early and ramping down to 0.2 x 10^20 m^-2.
Still got hard x rays. No H-mode. |
| Mar 11 2008 12:32:13:650PM | 1080311013 | Joseph Snipes | Shot 13: Try increasing the density to 0.35 x 10^20 m^-2 early and ramping down to 0.2 x 10^20 m^-2. Very few hard x rays, though they are still visible on each fast scanning probe scan. Still no H-mode. It seems there was a machine cryo induced leak just before this shot that increased Prad significantly, but there was also an increase in Prad due to argon. So, we will switch off the argon for shot 14. |
| Mar 11 2008 12:36:26:603PM | 1080311014 | Joseph Snipes | Shot 14: Try again with no argon and hopefully no leak. Got the H-mode at 1.46 s at nl04 = 0.23 x 10^20 m^-2 corresponding to nebar = 0.41 x 10^20 m^-3 at 2.2 T. |
| Mar 11 2008 12:50:43:570PM | 1080311015 | Joseph Snipes | Shot 15: Try again with slightly lower initial density. Got the H-mode at 1.56 s at nl04 = 0.23 x 10^20 m^-2 corresponding to nebar = 0.4 x 10^20 m^-3 at 2.2 T. |
| Mar 11 2008 01:02:46:977PM | 1080311016 | Joseph Snipes | Shot 16: Try again with no NINJA puff. Also program nl04 to 0.19 x 10^20 m^-2.
Density ramps down to 0.14 x 10^20 m^-2. No H-mode. |
| Mar 11 2008 01:19:37:273PM | 1080311017 | Joseph Snipes | Shot 17: Increase nl04 to 0.21 x 10^20 m^-2. Got 0.2 x 10^20 m^-2 but no H-mode. |
| Mar 11 2008 01:47:12:493PM | 1080311018 | Joseph Snipes | Shot 18: Try raising Ip to 0.5 MA at this density. Still no H-mode up to twice the old H-mode threshold scaling. |
| Mar 11 2008 01:50:23:697PM | 1080311019 | Joseph Snipes | Shot 19: Try raising Ip to 0.55 MA at this density. Got the H-mode at nl04 = 0.2 x 10^20 m^-2 corresponding to nebar = 0.34 x 10^20 m^-3. However, the power required is 2.2 times the old H-mode threshold scaling. This completes the low density limit to the Ohmic H-mode threshold experiment. |
| Mar 11 2008 03:32:27:697PM | 1080311020 | Jerry Hughes | Starting on TS calibration against ECE cutoffs.
Target: 800kA, 3.9T, density ramp to near n/n_G~1 Having Bob turn off the DNB, because of pick-up. Shot went pretty much as programmed. Plasma survives some MHD at ~.5s and fuels up to a disruption at nl04<2e20. Piezo is puffing pretty hard to fuel up the discharge to the demand level, and overshoots as a result. Got 8 cutoffs in the GPC, giving correction factors: Core TS 1: 1.11 +/- 0.13 Core TS 2: 0.94 +/- 0.11 Core TS 3: 1.00 +/- 2.00 Core TS 4: 1.04 +/- 0.12 Core TS 5: 0.89 +/- 0.10 Core TS 6: 1.00 +/- 2.00 Core TS 7: 0.97 +/- 0.11 Core TS 8: 0.99 +/- 0.11 Core TS 9: 1.00 +/- 2.00 Core TS 10: 0.98 +/- 0.12 Core TS 11: 1.00 +/- 2.00 Core TS 12: 1.00 +/- 2.00 Edge TS : 1.00 +/- 2.00 Got 5 cutoffs in GPC2, giving corrections: Core TS 1: 1.06 +/- 0.04 Core TS 2: 1.00 +/- 1.00 Core TS 3: 1.24 +/- 0.04 Core TS 4: 1.00 +/- 1.00 Core TS 5: 1.00 +/- 1.00 Core TS 6: 0.98 +/- 0.04 Core TS 7: 1.00 +/- 1.00 Core TS 8: 1.00 +/- 1.00 Core TS 9: 1.00 +/- 1.00 Core TS 10: 1.00 +/- 1.00 Core TS 11: 1.00 +/- 1.00 Core TS 12: 2.62 +/- 7.29 Edge TS : 1.00 +/- 1.00 Next shot: raise Bt to 4.0T, Change nl04 demand to a more modest ramp of 1.0--1.8e20, again from 0.6 to 1. |
| Mar 11 2008 02:34:53:290PM | 1080311021 | Jerry Hughes | Fizzle. Retry. |
| Mar 11 2008 03:36:20:103PM | 1080311022 | Jerry Hughes | Target: 800kA, 4.0T, nl04 1.0--1.8e20 from 0.6 to 1.0s
7 cutoffs in GPC, giving corrections: Core TS 1: 1.00 +/- 2.00 Core TS 2: 0.95 +/- 0.11 Core TS 3: 1.25 +/- 0.14 Core TS 4: 1.00 +/- 2.00 Core TS 5: 1.00 +/- 2.00 Core TS 6: 0.93 +/- 0.11 Core TS 7: 0.99 +/- 0.12 Core TS 8: 1.00 +/- 2.00 Core TS 9: 0.68 +/- 0.07 Core TS 10: 0.93 +/- 0.11 Core TS 11: 1.52 +/- 0.18 Core TS 12: 1.00 +/- 2.00 Edge TS : 1.00 +/- 2.00 5 cutoffs in GPC2, giving corrections: Core TS 1: 1.19 +/- 0.07 Core TS 2: 0.93 +/- 0.04 Core TS 3: 1.00 +/- 1.00 Core TS 4: 1.04 +/- 0.05 Core TS 5: 1.00 +/- 1.00 Core TS 6: 1.00 +/- 1.00 Core TS 7: 1.00 +/- 0.03 Core TS 8: 1.00 +/- 1.00 Core TS 9: 1.00 +/- 1.00 Core TS 10: 1.00 +/- 1.00 Core TS 11: 1.00 +/- 1.00 Core TS 12: 1.00 +/- 1.00 Edge TS : 1.00 +/- 1.00 Still have an overshoot in density. For next shot, change nl04 ramp timing from 0.7 to 1.1s, then drop nl04 demand to zero at 1.3s. Also make a change in lower X-point to obtain higher delta_lower, get outermost core TS channel deeper into the plasma. |
| Mar 11 2008 03:04:25:870PM | 1080311023 | Jerry Hughes | Fizzle. Retry. |
| Mar 11 2008 03:41:31:260PM | 1080311024 | Jerry Hughes | Target: 800kA, 4.0T, nl04 1.0--1.8e20 from 0.7 to 1.0s
Shot looks pretty good, though it still overfuels to a disruption. 7 cutoffs in GPC. Core TS 1: 1.00 +/- 2.00 Core TS 2: 0.97 +/- 0.12 Core TS 3: 1.24 +/- 0.14 Core TS 4: 1.00 +/- 2.00 Core TS 5: 1.00 +/- 2.00 Core TS 6: 0.96 +/- 0.11 Core TS 7: 1.04 +/- 0.13 Core TS 8: 1.00 +/- 2.00 Core TS 9: 1.00 +/- 2.00 Core TS 10: 1.00 +/- 2.00 Core TS 11: 1.53 +/- 0.18 Core TS 12: 1.00 +/- 2.00 Edge TS : 1.00 +/- 2.00 4 cutoffs in GPC2: Core TS 1: 1.00 +/- 1.00 Core TS 2: 0.95 +/- 0.04 Core TS 3: 1.00 +/- 1.00 Core TS 4: 1.00 +/- 1.00 Core TS 5: 0.86 +/- 0.02 Core TS 6: 0.96 +/- 0.04 Core TS 7: 1.04 +/- 0.03 Core TS 8: 1.00 +/- 1.00 Core TS 9: 1.00 +/- 1.00 Core TS 10: 1.00 +/- 1.00 Core TS 11: 1.00 +/- 1.00 Core TS 12: 1.00 +/- 1.00 Edge TS : 1.00 +/- 1.00 Next: raise Bt to 4.1T |
| Mar 11 2008 03:47:47:570PM | 1080311025 | Jerry Hughes | Target: 800kA, 4.1T, nl04 1.0--1.8e20 from 0.7 to 1.0s
Not a fizzle. Great shot. 7 cutoffs in GPC: Core TS 1: 1.07 +/- 0.12 Core TS 2: 1.00 +/- 2.00 Core TS 3: 1.00 +/- 2.00 Core TS 4: 1.02 +/- 0.11 Core TS 5: 0.87 +/- 0.10 Core TS 6: 1.00 +/- 2.00 Core TS 7: 0.99 +/- 0.11 Core TS 8: 1.02 +/- 0.12 Core TS 9: 0.78 +/- 0.09 Core TS 10: 0.98 +/- 0.11 Core TS 11: 1.58 +/- 0.18 Core TS 12: 1.53 +/- 0.18 Edge TS : 1.00 +/- 2.00 4 cutoffs in GPC2: Core TS 1: 1.04 +/- 0.04 Core TS 2: 1.00 +/- 1.00 Core TS 3: 1.26 +/- 0.05 Core TS 4: 1.00 +/- 1.00 Core TS 5: 1.00 +/- 1.00 Core TS 6: 0.91 +/- 0.02 Core TS 7: 1.00 +/- 1.00 Core TS 8: 1.01 +/- 0.03 Core TS 9: 1.00 +/- 1.00 Core TS 10: 1.00 +/- 1.00 Core TS 11: 1.00 +/- 1.00 Core TS 12: 1.00 +/- 1.00 Edge TS : 1.00 +/- 1.00 Next: |
| Mar 11 2008 04:28:34:963PM | 1080311026 | Jerry Hughes | Target: 800kA, 4.2T, nl04 1.0--1.8e20 from 0.7 to 1.0s
6 cutoffs from GPC: Core TS 1: 1.00 +/- 2.00 Core TS 2: 0.97 +/- 0.11 Core TS 3: 1.27 +/- 0.14 Core TS 4: 1.00 +/- 2.00 Core TS 5: 1.00 +/- 2.00 Core TS 6: 0.94 +/- 0.11 Core TS 7: 1.00 +/- 2.00 Core TS 8: 1.00 +/- 2.00 Core TS 9: 0.72 +/- 0.08 Core TS 10: 1.00 +/- 2.00 Core TS 11: 1.00 +/- 2.00 Core TS 12: 1.00 +/- 2.00 Edge TS : 1.00 +/- 2.00 4 cutoffs from GPC2: Core TS 1: 1.04 +/- 0.05 Core TS 2: 0.95 +/- 0.03 Core TS 3: 1.00 +/- 1.00 Core TS 4: 1.00 +/- 1.00 Core TS 5: 1.00 +/- 1.00 Core TS 6: 1.00 +/- 1.00 Core TS 7: 0.97 +/- 0.03 Core TS 8: 1.00 +/- 1.00 Core TS 9: 0.78 +/- 0.03 Core TS 10: 1.00 +/- 1.00 Core TS 11: 1.00 +/- 1.00 Core TS 12: 1.00 +/- 1.00 Edge TS : 1.00 +/- 1.00 That's enough for today. Giving run over to Brian for discharge development. |
| Mar 11 2008 04:37:04:337PM | 1080311027 | Brian Labombard | 27- LSN, NL04=0.75, Ip=0.8, Bt down to 2.8, EFH at 0.9 s forgot to ramp Bt back up |
| Mar 11 2008 04:52:51:180PM | 1080311029 | Brian Labombard | 29- LSN, NL04=0.63, Ip=0.8, Bt down to 2.8 then up, EFH at 0.9 s |
| Mar 11 2008 05:01:33:197PM | 1080311030 | Brian Labombard | 30- USN, NL04=0.77, Ip=0.8, Bt down to 2.8 then up. L-mode |
| Mar 11 2008 05:09:02:930PM | 1080311031 | Brian Labombard | 31- USN, NL04=0.53, Ip=0.8, Bt down to 2.8 then up. L-mode Disrupts at 0.9 s, q~3. |
| Physics Operator Comments | |||
| Mar 11 2008 09:01:29:010AM | Robert Granetz | Loaded 1080305025 (all segments). Seg 2 is active. Programmed BTOR in seg 2 to 61 kA (2.2 T). Set Ip to 0.6 MA. nl_04 already was 0.4e20 m-2. | |
| Mar 11 2008 09:12:56:540AM | 1080311001 | Robert Granetz | Shot 01 -- Plasma. Good shot. Btor gets down to 2.38 T around t=1.15 s. Ip=0.60 MA. nl_04=0.40e20 m-2. Ohmic OH mode starts at t=1.25 s. q95=2.8 when it goes into H-mode. Next shot: Adjust Btor to 2.2 T |
| Mar 11 2008 09:22:10:180AM | 1080311002 | Robert Granetz | Shot 02 -- Plasma. Good shot. Btor=2.2 T after t=1.18 s. Ohmic H-mode starts at t=1.07 s. Next shot: decrease Ip to 550 kA. |
| Mar 11 2008 09:31:41:853AM | 1080311003 | Robert Granetz | Shot 03 -- Plasma. Good shot. Ip=0.55 MA. Went into H-mode when Btor was at 2.25 T. Next shot: reduce Ip to 0.50 MA. |
| Mar 11 2008 09:46:46:290AM | 1080311004 | Robert Granetz | Shot 04 -- Plasma. Good shot. Got the H-mode. Next shot: reduce Ip to 450 kA. |
| Mar 11 2008 09:56:49:463AM | 1080311005 | Robert Granetz | Shot 05 -- Plasma. Good shot. Just barely went into H-mode. 2.2 T, 0.45 MA, 0.37e20 m-2. Next shot: decrease nl_04 to 0.35e20 m-2. |
| Mar 11 2008 10:18:39:400AM | 1080311006 | Robert Granetz | Shot 06 -- Plasma. Good shot. Got the H-mode again just before the end of flattop. Got nl_04=0.35e20 m-2. Next shot: reduce nl_04 to 0.30e20 m-2. Jim Terry will start NINJA puffing. |
| Mar 11 2008 10:37:50:417AM | 1080311007 | Robert Granetz | Shot 07 -- Plasma. Good shot. nl_04=0.30e20 m-2, but still got an H-mode at 2.2 T. So maybe there really is a B-field dependence on the low density H-mode threshold. That would be bad for higher-field machines (such as ITER). Next shot: reduce nl_04 to 0.25e20 m-2; extend Ip flattop to t=1.6 s. (This required extensions to CLEARIN, RXL, ZXL, RXU, NL_04, and IC_EF4U, in addition to Ip.) |
| Mar 11 2008 11:08:06:493AM | 1080311008 | Robert Granetz | Cell access after shot 08 to reboot HIREX computer and to check on scanning probes. |
| Mar 11 2008 11:10:56:010AM | 1080311008 | Robert Granetz | Shot 08 -- Plasma. Good shot. Still got an H-mode. Flattop extension to t=1.6 s worked well. Got nl_04=0.25e20 m-2. Ip=0.45 MA, Bt=2.2 T Next shot: decrease nl_04 to 0.20e20 m-2. Enable argon, 75 ms pulse. |
| Mar 11 2008 11:36:41:133AM | 1080311009 | Robert Granetz | Shot 09 -- Plasma. Good shot. No H-mode (finally). Got nl_04=0.20e20 m-2, but also got some hard x-rays. Next shot: tweak the density to start at nl_04=0.25e20 m-2 and then drop down to 0.20e20 m-2 early in the flattop |
| Mar 11 2008 11:42:29:180AM | 1080311010 | Robert Granetz | Shot 10 -- Plasma. Good shot. No H-mode. Still have hard x-rays. Next shot: increase the early density to 0.30e20 m-2, then drop to 0.20e20 m-2; also lengthen argon pulse to 100 ms. |
| Mar 11 2008 11:47:04:040AM | 1080311011 | Robert Granetz | Shot 11 -- No-power shot. Alternator excitation didn't come on in time during CHECK state. Next shot: try again |
| Mar 11 2008 12:01:31:150PM | 1080311012 | Robert Granetz | Shot 12 -- Plasma. Good shot. Still a bit of hard x-rays during rampup, and also when the scanning probe is in. No H-mode. Next shot: increase pre-fill to 26 ms (from 21 ms) to avoid early hard x-rays; increase early nl_04 to 0.35e20 m-2. |
| Mar 11 2008 12:12:34:213PM | 1080311013 | Robert Granetz | Shot 13 -- Plasma. Good plasma. No H-mode. nl_04=0.26e20 m-2, which is a little higher than we want, and similar to shot 08, which had an H-mode. Next shot: disable the argon valve |
| Mar 11 2008 12:33:11:150PM | 1080311013 | Robert Granetz | There is an N2 leak that Maria just alerted me to. Torus pressue is up to 7e-6 torr, with lots of N2. This time the cryopump has not been on at all today. Vessel temp is 17 C. Turned down the cooling, and the pressure and N2 came down to normal levels. Vessel temp is now 23 C. Ready for shot 14. |
| Mar 11 2008 12:44:40:430PM | 1080311014 | Robert Granetz | Shot 14 -- Plasma. Good shot. No argon this shot. Got a little H-mode back. nl_04=0.23-0.24 m-2. Next shot: We'll keep the argon OFF for the rest of this run. Repeat, hoping that nl_04 will drop down to 0.20e20 m-2, as programmed. Lower the initial density program to 0.32e20 m-2 (was 0.35) |
| Mar 11 2008 12:55:49:930PM | 1080311015 | Robert Granetz | Shot 15 -- Plasma. Good shot. Got a little H-mode very late. nl_04 is still 2.3-2.4e19 m-2. NINJA is still on. Next shot: Turn off NINJA. Decrease nl_04 to 0.19e20 m-2 during the latter part of the flattop. |
| Mar 11 2008 01:16:48:523PM | 1080311016 | Robert Granetz | Shot 16 -- Plasma. Good shot. No H-mode. nl_04 gets down to 0.14e20 m-2. Almost no hard x-rays. So that's below the ""low density limit"" for H-modes at this Btor of 2.2 T. Next shot: increase nl_04 to 0.21e20 m-2. |
| Mar 11 2008 01:20:36:883PM | 1080311017 | Robert Granetz | Shot 17 -- Plasma. Good shot. No H-mode. nl_04=0.20 +/- 0.02 e20 m-2. Next shot: raise Ip to 0.50 MA. |
| Mar 11 2008 01:40:55:587PM | 1080311018 | Robert Granetz | Shot 18 -- Plasma. Good shot. Ip=0.50 MA; nl_04=0.20e20 m-2. No H-mode. Next shot: raise Ip to 0.55 MA. |
| Mar 11 2008 01:50:41:963PM | 1080311019 | Robert Granetz | Shot 19 -- Plasma. Good shot. Ip=0.55 MA, nl_04=0.20e20 m-2. Got the H-mode. Poh is 2.2 times the old H-mode threshold scaling. So this density is really the density threshold. That finishes this miniproposal. Next shot: change to Thomson scattering calibration shots. Reload shot 01 from today; set Btor=3.9 T; program nl_04 to ramp from 1.2e20 at t=0.6 s to 2.0e20 m-2 at t=1.0 s. Re-enable the argon puff (100 ms). |
| Mar 11 2008 02:09:09:070PM | 1080311020 | Robert Granetz | Shot 20 -- Plasma. Good shot. Got the ECE cutoff at Bt=3.9 T and nl_04=1.6e20 m-2. High density disruption at t=1.36 s. Next shot: decrease pre-fill by 4 ms; decrease nl_04 by 0.2 throughout the shot; raise Bt to 4.0 T. |
| Mar 11 2008 02:11:56:290PM | 1080311020 | Robert Granetz | A small air leak seems to be developing. Will need to wait a few minutes for the base pressure to get down to the low 10-6 torr scale. |
| Mar 11 2008 02:19:31:040PM | 1080311021 | Robert Granetz | Shot 21 -- Fizzle. Chalk it up to post-disruption recovery. Next shot: repeat; keep pre-fill as is. |
| Mar 11 2008 02:52:45:680PM | 1080311022 | Robert Granetz | Shot 22 -- Plasma. Good shot. Got ECE cutoff at 4.0 T and nl_04=1.5e20 m-2. High density disruption at t=1.54 s. Next shot: reduce pre-fill by 4 ms (to 18 ms); move ZXL down by 5 mm and RXL out by 5 mm. Delay start of density ramp until t=0.7 s; Turn off density harder, starting at t=1.4 s. |
| Mar 11 2008 02:57:43:667PM | 1080311023 | Robert Granetz | Shot 23 -- Fizzle. Pre-fill pressure was good and low (0.050 mTorr), so it must just be post-disruption dirt. Next shot: add 2 ms to pre-fill and try again. |
| Mar 11 2008 03:23:34:807PM | 1080311024 | Robert Granetz | Shot 24 -- Plasma. Good shot. Got the ECE cutoff at 4.0 T. Still got a high density disruption at t=1.55 s, so I'll still have to deal with the fizzles. Next shot: Try reducing pre-fill by 4 ms, but this probably won't help because I think it's a dirt issue. Raise Btor by 0.1 T (to 4.1 T). |
| Mar 11 2008 03:48:50:993PM | 1080311025 | Robert Granetz | Shot 25 -- Plasma. Good shot. Got the ECE cutoff at Bt=4.04 T (wanted 4.1 T). Disrupted halfway down the ramp, which is a substantial improvement. Next shot: add 1 ms to pre-fill; increase Btor by another 0.1 T. |
| Mar 11 2008 04:13:46:773PM | 1080311026 | Robert Granetz | Shot 26 -- Plasma. Good shot. Got the ECE cutoff at Bt=4.14 T. That finishes up the Thomson cross-calibration run. Next shot: Start on Brian's MP493 Ohmic L-H threshold experiments. Load seg 2 from 1080305025 seg 2; set Btor=2.7 T; set nl_04=0.6e20 m-2; |
| Mar 11 2008 04:55:14:853PM | 1080311027 | Robert Granetz | Shot 27 -- Plasma. Ip=0.8 MA, Bt=2.8 T, nl_04=0.7e20 m-2. Got an ELMfree H-mode and the density just kept climbing until the shot disrupted at t=1.44 s. Next shot: disruption recovery...reduce pre-fill by 3 ms (to 14 ms); add 14 mm to ZCUR to try for upper null |
| Mar 11 2008 04:54:46:727PM | 1080311028 | Robert Granetz | Shot 28 -- Fizzle. Disruption recovery. Pre-fill pressure was good and low (0.042 mTorr). Next shot: add 2 ms to pre-fill; load Btor programming from 1080124018 seg 2 into seg 2 (ramp down, then back up) |
| Mar 11 2008 04:50:45:150PM | 1080311029 | Robert Granetz | Shot 29 -- Plasma. It never made it all the way to upper null. Lithium pellet disrupted the plasma at t=1.53 s. Next shot: reload shot 1080124018 (seg 3 was active)...this is an upper null shot; reload seg 1 from 1080311029. No LPI. Sutract 2 ms from pre-fill. Tweak nl_04 to 6.0e19 m-2 |
| Mar 11 2008 04:59:24:273PM | 1080311030 | Robert Granetz | Shot 30 -- Plasma. Full-length shot; upper null; no H-modes. Btor is ramping down than back up a bit, on purpose (inherited). nl_04=0.75e20 m-2. Next shot: add 2 ms to pre-fill; reduce nl_04 to 0.4e20 m-2. |
| Mar 11 2008 10:20:13:503PM | 1080311031 | Robert Granetz | Shot 31 -- Plasma. Disrupts at t=0.90 s. Got nl_04=0.5e20 m-2. I
think the disruption was due to a locked mode, which in turn is due to the lower density. End of run. |
| Engineering Operator Comments | ||||
| Shot | Time | Type | Status | Comment |
| 1 | 09:00:34:320AM | Plasma | Ok | |
| 2 | 09:14:23:337AM | Plasma | Ok | |
| 3 | 09:26:51:463AM | Plasma | Ok | |
| 4 | 09:39:22:447AM | Plasma | Ok | |
| 5 | 09:51:49:447AM | Plasma | Ok | |
| 6 | 10:04:23:057AM | Plasma | Ok | |
| 7 | 10:20:47:243AM | Plasma | Ok | |
| 8 | 11:01:42:523AM | Plasma | Ok | |
| 9 | 11:15:50:070AM | Plasma | Ok | |
| 10 | 11:28:19:243AM | Plasma | Ok | |
| 11 | 11:41:55:273AM | Plasma | Bad | No Alternator Excitation |
| 12 | 11:53:23:010AM | Plasma | Ok | |
| 13 | 12:05:41:273PM | Plasma | Ok | |
| 14 | 12:31:53:807PM | Plasma | Ok | |
| 15 | 12:46:50:477PM | Plasma | Ok | |
| 16 | 12:59:29:697PM | Plasma | Ok | |
| 17 | 01:14:41:400PM | Plasma | Ok | |
| 18 | 01:27:19:307PM | Plasma | Ok | |
| 19 | 01:40:41:760PM | Plasma | Ok | |
| 20 | 01:56:03:337PM | Plasma | Ok | |
| 21 | 02:16:32:620PM | Plasma | Ok | |
| 22 | 02:32:58:667PM | Plasma | Ok | |
| 23 | 02:53:17:180PM | Plasma | Ok | |
| 24 | 03:05:35:120PM | Plasma | Ok | |
| 25 | 03:34:07:180PM | Plasma | Ok | |
| 26 | 03:50:07:820PM | Plasma | Ok | |
| 27 | 04:13:26:493PM | Plasma | Ok | |
| 28 | 04:27:43:760PM | Plasma | Ok | |
| 29 | 04:40:11:837PM | Plasma | Ok | |
| 30 | 04:52:31:447PM | Plasma | Ok | |
| 31 | 05:04:48:120PM | Plasma | Ok | |
| System Availability | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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