| Miniproposals | ||||||||||
| ||||||||||
|
| Operators | |
| Session leader(s): | Dennis Whyte,Earl Marmar |
| Physics operator(s): | Bill Rowan |
| Engineering operator(s): | Bill Cochran,Bill Byford |
| Engineering Operator Run Comment |
| automatically entered by signon - please replace with real comment |
| Session Leader Plans |
| Entered: Jan 8 2008 09:06:11:240AM |
| Author: Dennis Whyte |
| Post-Boronization discharges that minimize boron erosion
Last evening was the first boronization of this run campaign. The goal for this "recovery" period will be to develop discharge conditions that optimize the rapid conditioning of ICRH while minimizing the erosion of B films in location of importance of standard LSN shapes. The idea will be to run LSN discharges that have the outer strikepoint on the horizontal target, i.e. a deep slot divertor. This is motivated by the concern that flux surfaces connected to the ICRH antennae are causing enhanced erosion, first of the boron then the underlying molybdenum, via sheath rectification. Therefore it's advantageous to first condition ICRH with the strikepoints away from their typical position in order to minimize the B film erosion in the regions where it's needed for high performance. This was previously tried with USN shapes, but the "stuff" falling from the top was not good for conditioning. We will use the high triangularity JFT2M shape as our staring point, with reference shot LSN 1060719011. We will first establish ohmic shots with this shape, in order to set the proper line averaged density for ICRH conditioning and to tweak the outer gap such that as few flux surfaces as possible are linked between the ICRH antennae and the lower outer divertor. The motivation for this is to minimize ICRH Joule throughput until we have the right shape. Then we will bring up IRCH to reliable operation. If H/D looks good and the ICRH is operating reliably, we will then hand over the experiment to a performance oriented MP. |
| Entered: Jan 8 2008 11:12:03:460AM |
| Author: Earl Marmar |
| Plan for 1080108 (afternoon)
MP 496, High Performance operation at Ip > 1.2 MA This run is the first day following the first boronization of the FY08 campaign. The purpose of these experiments is to explore the confinement, transport, pedestal scaling and divertor behavior as plasma current is scanned above 1.2 MA using hydrogen minority heating, with maximum power available. Ideally, these experiments will be carried out using the nominal ITER shape, with a target to reach 1.6 MA, which should yield the ITER q_95 at the ITER magnetic field. If we can access these parameters with 6 MW of input power (ICRF + Ohmic), and good H-Mode confinement (H89 ~ 1.8), the resulting plasma will have the same absolute pressure and β as the baseline ITER H-Mode discharge target. Exploration of this territory should significantly expand our parameter ranges for studies of confinement (particularly scaling with Ip), the H-mode pedestal, including ELM character, and spontaneous rotation. These experiments will directly contribute to one of the C-Mod plain English goals for FY2008, Confinement at High Plasma Current. Elucidation of these results for extrapolation to ITER will be a major goal of these studies. Run Plan Overnight boronization prior to the run. See the PO_Plan for other engineering setup information. Cryopump should be on for all shots, to keep edge neutral pressure down for the ICRF. 1) Ip = 1.35 MA, nl_04 target = 1.4 e20 m-2, establish EDA H-Mode at PRF = 3.5 MW. Use 1070829028 as template for the shot, but with increased target nl_04. This is a near double-null equilibrium. 2) Increase ICRF power shot by shot, in .5 MW increments, until maximum available. 3a) If successful, go to 1.5 MA, nl_04 target = 1.6 e20, P_RF = 4 MW. If these run without disruption, increase ICRF power shot by shot to maximum available. 3b)If 1.5 MA is disrupting, go down to 1.2 MA, nl_04 target = 1.25e20, P_RF = 3.5 MW and then increase ICRF power shot by shot to maximum available. |
| Physics Operators Plans |
| Entered: Jan 8 2008 07:06:52:753AM |
| Author: Bill Rowan |
| Physop Run Plan for Tuesday, 8-Jan-2008; 1080108
Purpose: MP484 Post-Boronization Discharges that Minimize Boron Erosion MP496 High performance ops at Ip > 1.2 MA MP484 in the am. MP496 in the pm if boronization recovery is quick SL: Whyte (MP484), Marmar (MP496) PO: Rowan ----------------- Engineering Setup ----------------- Run begins at 09:00 and ends at 17:00 Power systems as on: 1060719011 Acoil: +Dtop -Dbot -Jtop +Jbot (standard) Hybrid Enabled 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) fill NINJA with 10 psi D2 DISABLED Enable gatevalves and shutters: ECE, VUV, DNB, Z-bolo Torvac gatevalve toggle (yes/no): no Boronization(yes/no): yes ICRF(yes/no): yes LH(yes/no): no DNB(yes/no): yes Cryopump (yes/no): no Vessel temperature: 35/35/35 |
| Session Leader Summaries |
| Entered: Jan 8 2008 04:17:27:480PM |
| Author: Dennis Whyte |
| The BZN recovery was successful in the sense that we were
able to hand over to a physics experiment at about 1:30 pm. We made the LSN shape we desired with the "RF-conncected flux surfaces" going to the horizontal outer divertor plate. After some tuning and conditioning the RF power came up on all the sources up to total ~4.5 MW. Eventually, but shot 13, the RF input energy became limited by the presence of type-I ELMs, which were expected in this shape. It was then deemed appropriate to change over the experiment. On the physics side we had interesting features in the H-modes. Beside the type-I ELMs, which were readily obtained on each discharge, we also saw a broad fluctuation feature at ~800 kHz associated with this H-mode. The Prad was relatively well controlled through most of the day. These would be a good candidate for ELM suppression with the error-field coils. We saw the wall evolve from outgassing to pumping near the end of the recovery (gate valves were closed today) , which is consistent with previous observations. The effectiveness of doing recovery with this shape in keeping BZN layers around will be evaluated in the next campaign this afternoon. |
| Entered: Jan 9 2008 12:10:17:960PM |
| Author: Earl Marmar |
| No real progress on the MP today. We got a number of 1.35 MA shots to run through, but there was not enough steady ICRF power to test confinement.
As seen in the past, h-modes tend to be ELM-free at these high currents; raising the density to try to access EDA leads to edge neutral pressures that cause problems for the ICRF, even with the cryopump on in these essentially double null shots. There were several shots (19, 20, 21, 22, 24) which stayed in H-mode after the RF turned off, typically until the end of current flat-top, which might be of interest for ohmic h-mode studies. |
| Physics Operator Summaries |
| Entered: Jan 8 2008 05:51:20:257PM |
| Author: Bill Rowan |
| Physop Summary for Tuesday, 8 Jan 2008, 1080108
C-Mod was boronized before this run. Shots 001 to 013 were for MP484 (Post-Boronization Discharges that Minimize Boron Erosion). See SL summary for details. Note that the H/D ratio rose from approx 0.03 on shot 001 to approx 0.07 on shot 013. The JFT2M shape (1060719011) reproduced well for this run. One disruption during this sequence led to a fizzle on the following shot. Shots 014 to 024 were for MP496 (High performance ops at Ip > 1.2 MA) The plasma shape was changed for this sequence of shots to a shape that was close to a double null (1070829028). The H/D ratio was 0.04 for the first shot in the sequence and was 0.08 at the end. Problems with ICRF coupling may have limited the utility of this sequence of shots. The coupling was improving shot by shot at the end of the run. One high current disruption was followed by 3 fizzles. Score Card 19 Plasmas (001,002,003,004,005,006,007,008,009(Disruption at 1.3s),011,012,013,014,015(Disruption at 1.14s),019,020,021,022,024 04 Fizzles (010,016,017,018) 01 Engineering (023 No power shot) -------- 24 Total |
| Session Leader Comments | |||
| Jan 8 2008 09:42:29:240AM | 1080108001 | Dennis Whyte | Shot ran well.
Injection, apparently from inner wall according to Dant camera at 0.8 s. Plasma recovers (barely) H/H+D ~ 2-4 %. LSN divertor shape looks good, we will now reduce outer gap to ensure flux surfaces connected to ICRH go to horizontal target. Wall (boron layers) was fuelling the plasma. Barely any fuel injection was required for discharge (~ 0 Torr-L), but got ~9 Torr-L after the shot with gate valves closed. |
| Jan 8 2008 10:02:03:233AM | 1080108002 | Dennis Whyte | Outer gap reduced to ~1.5 cm.
Shape looks good from 0.75 - 1.4 seconds. Will inject Rf on next shot over this time. Demand nl04 was only 3e19, with the wall outgassing this is why the external fuelling never turned on in shots 1 or 2. Net outgassing ~ 8 Torr-L on this shot. |
| Jan 8 2008 10:10:53:620AM | 1080108003 | Dennis Whyte | Got ~ 1 MW RF into plasma. Target L-Mode density was raised to ~ 8e19 on NL04
matching on on J and D was poor so they dropped out frequently. E with FFT gave fairly constant 1 MW, giving us decent H-mode (assume EDA since line averaged density is constant. Fuelled 14 Torr-L Recovered 15.6 Torr-L H/H+D looks OK: ~ 3-4% |
| Jan 8 2008 10:44:55:840AM | 1080108004 | Dennis Whyte | Got ~ 2 MW RF into plasma. Target L-Mode density ~ 8e19 on NL04
Good matching on D and E from 1 - 1.35 seconds. Got a nice constant EDA with H-alpha showing a periodic oscillation. With constant input power, Prad actually decreased from 1.2 MW to 0.75 MW during this phase. Peak neutron rate ~ 1e13 n/s. J still having problems. Will lower target density for next shot to see if this helps. Fuelled 10 Torr-L Recovered 19 Torr-L Magnetic show interesting high frequency fluctuations at ~800 kHz but not a clear QC mode. |
| Jan 8 2008 10:45:30:903AM | 1080108004 | Dennis Whyte | Got ~ 2 MW RF into plasma. Target L-Mode density ~ 8e19 on NL04
Good matching on D and E from 1 - 1.35 seconds. Got a nice constant EDA with H-alpha showing a periodic oscillation. With constant input power, Prad actually decreased from 1.2 MW to 0.75 MW during this phase. Peak neutron rate ~ 1e13 n/s. J still having problems. Will lower target density for next shot to see if this helps. Fuelled 10 Torr-L Recovered 19 Torr-L |
| Jan 8 2008 10:45:23:467AM | 1080108005 | Dennis Whyte | Got ~ 1.2 MW RF into plasma on both D an E. Target L-Mode density ~ 7.5e19 on NL04
higher than the demand (so density being set by wall fuelling) Injection at 0.87 s caused radiative disruption. J still having problems, but didn't get much of a chance with the disruption on this shot. Will repeat Fuelled 6.3 Torr-L Recovered 120 Torr-L !! Clearly the disruption out-gassed the wall. H/H+D ~ 5% |
| Jan 8 2008 11:09:56:753AM | 1080108006 | Dennis Whyte | 2-3 MW ICRH, since J is still dropping out. Will move to
vacuum conditioning of J for a while. Outer gap 1 cm. Got steady H-mode that has a mix of type 1 ELMs and "hash" Still see the 800 kHz fluctuations. H89 only 1.45 Fuelled 11.2 Torr-L Recovered 28.9 Torr-L Wall continues to outgas. H/H+D ~ 4-5% |
| Jan 8 2008 12:15:42:977PM | 1080108007 | Dennis Whyte | Shot following vacuum conditioning of J
Steady H-mode obtained. J was acting a bit better towards end of shot where we got periods of sustained RF ~ 3.4 MW. All RF dropped out at 0.84 s due to a large ELM. Will attempt another shot with different phasing on J. Again got a mix of ELMs and hash on Halpha Injected: 12.1 Torr-L Recovered: 10 Torr-L |
| Jan 8 2008 12:21:21:117PM | 1080108008 | Dennis Whyte | RF was very intermittent, partiuclalry J, but D was also tripping out
as the power was raised to 1.5 MW. H-mode with ELMs and hash Injected: 11.3 Torr-L Recovered: 11.5 Torr-L We're creeping closer to our demand density of 6e19 on NL04, consistent with the wall starting to pump a bit on the last shot. Also does this mean we're starting to dig through the B layers? |
| Jan 8 2008 12:51:23:823PM | 1080108009 | Dennis Whyte | RF intermittent again, although J did better at higher power?
disruption at 1.3 s, caused by a power supply railing (EF2) Fuelled: 14.5 Torr-L Recovered: 141 Torr-L |
| Jan 8 2008 01:19:23:783PM | 1080108012 | Dennis Whyte | RF was generally good, up to 4 MW, except it's becoming
clear that the ELMs are the primary reason for the RF dropping out (3-4 sources drop out at one time) Prad did at least flatten out in this shot. INjected: 17.8 Torr-l recovered: 12 Torr-L |
| Jan 8 2008 01:41:05:243PM | 1080108013 | Dennis Whyte | RF was good. The ELMs are the primary cause of RF dropouts,
otherwise in between ELMs we're getting Prf ~ 4.5 MW. Prad was constant ~ 1 - 1.25 MW during the H-mode. The "average" Rf power was ~ 2 MW due to RF dropouts from ELMs Since we cannot avoid ELMs in this shape, it seems like the appropriate time to switch over to Earl's epxt which has a more typical shape and will not ELM. INjected: 12.9 Torr-l recovered: 10.4 Torr-L |
| Jan 8 2008 01:55:58:127PM | 1080108014 | Earl Marmar | Plasma equilibrium looks good, got the target density. All ICRF antennas tripping; neutral pressure too high.
|
| Jan 8 2008 02:02:55:517PM | 1080108015 | Earl Marmar | Cryopump on.
Plasma disrupted at 1.15 s. ICRF still trippy. essentially no h-mode. |
| Jan 8 2008 02:10:21:403PM | 1080108016 | Earl Marmar | lower target density to 1.1e20
reduce outer gap to 1 cm (from 1.5 cm) fizzle |
| Jan 8 2008 03:07:41:333PM | 1080108019 | Earl Marmar | lower target density to 1.1e20
reduce outer gap to 1 cm (from 1.5 cm) plasma short h-mode with RF (ramping to 2.5 MW, then tripping) steady ohmic h-mode after 1.1 seconds H/(H+D) is up over 7% |
| Jan 8 2008 04:10:58:997PM | 1080108020 | Earl Marmar | long delay before this shot to fix the FFT computer
plasma ~1.2 MW from E-port only goes into h-mode just before E-port trips, stays in ohmic h-mode until end of current flattop |
| Jan 8 2008 04:26:48:977PM | 1080108021 | Earl Marmar | plasma
1.2 MW ICRF, short ELM-free h-mode, H_89 ~ 1.3 H/(H+D) ~ .06 |
| Jan 8 2008 04:43:32:203PM | 1080108022 | Earl Marmar | plasma
mostly 1 MW ICRF, H_89 ~ 1.25 H/(H+D) ~ .06 to .08 |
| Jan 9 2008 12:01:26:260PM | 1080108024 | Earl Marmar | plasma
briefly got 3 MW of ICRF in h-mode, Wtot to 180 kJ |
| Physics Operator Comments | |||
| Jan 8 2008 07:32:57:290AM | Bill Rowan | loaded 1060719011 (JFT2m shape)
will be using seg 2 from this shot recalculated the magnetics predictors for segs 2, 3, and 4 will load a recent seg 1 | |
| Jan 8 2008 08:04:28:607AM | Bill Rowan | Loaded 1080103029 segment 1
15 ms prefill. Note that the prefill is at -0.4 instead of -0.5. | |
| Jan 8 2008 08:53:09:243AM | Bill Rowan |
ninja not available changed gate valve to "closed after shot" for 300s | |
| Jan 8 2008 09:21:36:420AM | 1080108001 | Bill Rowan | 001. Plasma
Prefill pressure is 0.04 mT. Lower than the segment 1 that was loaded. Dip in the plasma current at 0.8 s. Correlates with 2 Pi bolometer increase. Something fell in. |
| Jan 8 2008 09:26:08:170AM | 1080108001 | Bill Rowan | Next shot.
Reduce the outer gap by 1 cm by increaseing rcur by 0.005 |
| Jan 8 2008 09:48:14:893AM | 1080108002 | Bill Rowan | 002. Plasma
Outer gap: between 1.2 and 1.5 cm. Actually programmed to be flat. inl_04 demand is 0.3e_20. so gas is obviously turning off Next shot. nl_04 demand increased to 0.7e+20. it was set at 0.3e_20 |
| Jan 8 2008 09:59:25:640AM | 1080108003 | Bill Rowan | 003. Plasma
ICRF on this shot nl_04 is 0.8e+20 rather than the demand of 0.7e+20. |
| Jan 8 2008 10:00:38:657AM | 1080108003 | Bill Rowan |
Next shot. No PCS changes |
| Jan 8 2008 10:18:11:243AM | 1080108004 | Bill Rowan | 004. Plasma
Next shot. nl_04 demand reduced to 0.6e_20 Improving ICRF |
| Jan 8 2008 10:27:57:753AM | 1080108005 | Bill Rowan | 005. Plasma
Disruption at 0.9 s after ICRF turned on. Density was 0.78e+19. Higher than the demand Next shot. No PCS changes. |
| Jan 8 2008 10:38:43:390AM | 1080108006 | Bill Rowan | 006. Plasma.
|
| Jan 8 2008 10:45:08:153AM | 1080108006 | Bill Rowan | Next shot.
Delay for approx 1 hour of vacuum conditioning of J |
| Jan 8 2008 11:24:51:700AM | 1080108006 | Bill Rowan | bbb |
| Jan 8 2008 12:11:58:620PM | 1080108007 | Bill Rowan | 007. Plasma
Approx 1.5 hour pause before this shot for j antenna conditioning. Next shot. No PCS changes |
| Jan 8 2008 12:12:30:400PM | 1080108008 | Bill Rowan | 008. Plasma |
| Jan 8 2008 12:51:50:963PM | 1080108010 | Bill Rowan | 010. Fizzle
Take this to be a post-disruption fizzle Next shot. No PCS changes |
| Jan 8 2008 12:51:34:793PM | 1080108011 | Bill Rowan | 011. Plasma
|
| Jan 8 2008 12:58:38:510PM | 1080108011 | Bill Rowan |
Next shot. No PCS changes |
| Jan 8 2008 01:06:51:210PM | 1080108012 | Bill Rowan | 012. Plasma
|
| Jan 8 2008 01:10:33:067PM | 1080108012 | Bill Rowan | Next shot.
No PCS changes |
| Jan 8 2008 01:34:28:777PM | 1080108013 | Bill Rowan | 013. Plasma
Next shot. Change to MP 496 Load from 1070829028 Recalculated the magnetics predictors Loaded segment 1 from 1080108013 nl_04 demand increased to 1.4e+20 |
| Jan 8 2008 01:50:41:753PM | 1080108014 | Bill Rowan | 014. Plasma
Next shot. Prefill increased to 35 ms Wait for cryo before the next shot. |
| Jan 8 2008 02:02:03:640PM | 1080108015 | Bill Rowan | 015. Plasma
Disruption at 1.14 s Next shot. Decreased nl_04 demand to 1.1e+20 Decreased the right gap by 0.5 cm by increasing rcur |
| Jan 8 2008 02:08:05:077PM | 1080108016 | Bill Rowan | 016. Fizzle
Post disruption fizzle as earlier in the day Next shot. No PCS changes |
| Jan 8 2008 02:37:43:253PM | 1080108018 | Bill Rowan | 018., Fizzle
Next shot. Decrease the prefill to 31 ms |
| Jan 8 2008 03:59:23:923PM | 1080108019 | Bill Rowan | 019. Plasma
Next shot. enable argon with pulse length of 100 ms ICRF problems. Requires a cell access. Required approx 1.3 hrs |
| Jan 8 2008 04:27:37:303PM | 1080108020 | Bill Rowan | 020. Plasma
Next shot. No PCS changes. ICRF changes to improve match |
| Jan 8 2008 04:27:19:430PM | 1080108021 | Bill Rowan | 021. Plasma
Next shot. Increase prefill by 4 ms to 35 ms |
| Jan 8 2008 04:52:43:137PM | 1080108022 | Bill Rowan | 022. Plasma
Next shot. No PCS changes |
| Jan 8 2008 04:53:37:420PM | 1080108023 | Bill Rowan | 023. No power shot
Computer problems during init Next shot No PCS changes |
| Engineering Operator Comments | ||||
| Shot | Time | Type | Status | Comment |
| 1 | 09:13:42:470AM | Plasma | Ok | |
| 2 | 09:40:00:290AM | Plasma | Ok | |
| 3 | 09:53:02:660AM | Plasma | Ok | |
| 4 | 10:06:28:997AM | Plasma | Ok | |
| 5 | 10:19:38:900AM | Plasma | Ok | |
| 6 | 10:32:18:720AM | Plasma | Ok | |
| 7 | 11:53:24:050AM | Plasma | Ok | |
| 8 | 12:08:09:637PM | Plasma | Ok | |
| 9 | 12:20:46:023PM | Plasma | Ok | |
| 10 | 12:36:20:343PM | Plasma | Ok | |
| 11 | 12:49:34:967PM | Plasma | Ok | |
| 12 | 01:02:25:397PM | Plasma | Ok | |
| 13 | 01:16:24:393PM | Plasma | Ok | |
| 14 | 01:37:49:853PM | Plasma | Ok | |
| 15 | 01:52:17:927PM | Plasma | Ok | |
| 16 | 02:05:51:483PM | Plasma | Ok | |
| 17 | 02:18:25:870PM | Plasma | Ok | |
| 18 | 02:31:12:973PM | Plasma | Ok | |
| 19 | 02:43:57:030PM | Plasma | Ok | |
| 20 | 04:03:25:547PM | Plasma | Ok | |
| 21 | 04:16:11:853PM | Plasma | Ok | |
| 22 | 04:28:49:770PM | Plasma | Ok | |
| 23 | 04:44:53:780PM | Plasma | Bad | Actmon data problem |
| 24 | 05:02:06:883PM | Plasma | Ok | |
| System Availability | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Jan 8 2008 09:13:16:317AM | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Feb 8 2008 01:34:12:200PM | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||