Miniproposals

Miniproposal: 299 Date Filed: 5/29/2002 Title: Formation and Decay of Ohmic H-mode ITB First Author: Catherine Fiore Session Leader: Catherine Fiore (shots 1-33)

Engineering Operator Run Comment

MP#299 ICRF into Ohmic H-mode ITB. Fiore/Irby/Cochran/Fitzgerald.

Session Leader Plans

Physics Operators Plans

Session Leader Summaries

Entered: Jul 7 2004 03:49:29:803PM

Author: To Be Determined

This run was intended to provide Ohmic H-mode targets with peaked density as targets for rf central power as described in MP 299. Overall, the run was quite successful with 29 plasmas out of 33 shots, and Ohmic H-modes appearing in all but one plasma shot. Forming the ITBs was not as easy as it had been on the 1000915 run. Although some density peaking was obtained on most shots during the final H-mode (t > 1.3 s) it was not nearly so dramatic as in the earlier run. On 9/15/2000, the Ohmic H-modes lasted for many hundreds of milliseconds, and had plenty of time to build up ITBs. On this run, they seldom lasted for more than 100 ms, and the H-modes typically terminated before significant peaking was obtained. The result was that there was never a strong ITB formed as an rf target. On the other hand, we found that the low power rf could easily sustain the H-modes and that the density would continue to peak up even with 0.8 to 1 MW rf power. The plasmas were all Ohmic until shot 9, when we started injecting low power rf at 1.3 s or later. The power was gradually increased to 1 MW by shot 26. From shot 28, the rf was fired at 1.1 s and used to sustain a longer lasting H-mode. Power was scanned from 0 to 1 MW for the remainder of the run, with an attempt to reach 2 MW failing on the last shot. Overall it was a great run with much material for more detailed analysis, even though it was not exactly according to plan. I would also note that there were a very large number of EN modes in this run because of the plasmas frequently dropped out of H-mode. Shot list: Shot 1 : Fizzle Shot 2: Several good but short lived H-modes. No Visible Bremsstrahlung data (VB). Shot 3: Several good H-modes, although they keep dropping out. VB data was collected. There is a slight rise in the density peaking during the H-mode which started at 1.3 s. Shot 4: Three good H-modes, still dropping out, although the first one lasted 250 ms. There is possibly ITB forming during the third H-mode. Shot 5: Commutation bank problem. Shot 6: Test Shot 7: Several H-modes. Shot 8: Two longer lasting H-modes. Shot 9: Two longer lasting H-modes. Not much sign of peaking on the density. Shot 10: Multiple H-modes, possible ITB at 1.3 s Shot 11: One short H-mode, none after field increase except at current ramp down. Shot 12: Multiple H-modes, it is possible that an ITB arose during the rf pulse, but the profiles will need to be checked more carefully. Shot 13: Multiple H-modes, It is possible that an ITB arose during the rf pulse, but the profiles will need to be checked more carefully. Shot 14: Multiple short H-modes, none long enough to build up an ITB Shot 15: No H-modes at all, but a good shot otherwise. Shot 16: Four H-modes, density peaking on the last one, beginning at 1.1 s Shot 17: Two good long H-modes. No significant density peaking. Shot 18: A single long EDA H-mode ITB starts building after 1.1s, drops out at 1.2, then continues growing through the remainder of the shot. Shot 19: Multiple H-modes. Density peaks, even with 200 kW rf on during the last H-mode. Shot 20: Multiple H-modes. Density starts to peak and stops, possibly starts to peak again with 200 kW rf. Shot 21: Multiple H-modes. Density is peaking on last H-mode, even with 200 kW of rf. We will raise the rf power on the next shot. Shot 22: Multiple H-modes. Density is peaking from 1.42 to 1.5s on last H-mode, 400 kW of rf on. Shot 23: Multiple H-modes. Density is peaking from 1.3 to 1.5s on last H-mode rising the full length of the 400 kW rf pulse. Shot 24: Multiple H-modes. Density is peaking from 1.3 to 1.5s on last H-mode rising the full length of the 600 kW rf pulse. Shot 25: Multiple H-modes. Density has slight peaking from 1.3 to 1.5 on last H-mode rising the full length of the 800 kW rf pulse. Shot 26:Multiple H-modes. Density no longer seems to be peaking from 1.3-1.5s Shot 27: Multiple H-modes. The last one ends in an EN without significant peaking. Shot 28: Multiple H-modes to begin with, one long one started just before the rf came on at 1.1 s and stayed on through the entire rf pulse. The density peaked up somewhat over the length of this last H-mode. Shot 29: Fizzle Shot 30: Multiple H-modes to begin with, one long one started just before the rf came on at 1.1 s and stayed on through the entire rf pulse. The density peaked up somewhat over the length of this last H-mode. Shot 31: Multiple H-modes throughout, but a long H-mode was not sustained at the end as it had been in 28 and 30. We will try to get it to go a second time. Shot 32: Multiple H-modes throughout, but a long H-mode was sustained at the end as it had been in 28 and 30. The density was also peaking during this last H-mode. We will try high power for the last shot. Shot 33: Multiple H-modes throughout, but a long H-mode was sustained at the end. The rf power cut off repeatedly, so we didn't get the sustained 2 MW we wanted. The modulation of the rf is affecting some of the outer VB channels so it is difficult to judge the peaking without a closer examination of the profiles.

Physics Operator Summaries

Entered: Jul 7 2004 04:37:15:833PM

Author: To Be Determined

Physics Operator Summary for Friday, Aug 16, 2002 MP#299 ICRF into Ohmic H-mode ITB SL: Fiore PO: Irby EO: Cochran, Fitzgerald Engineering Setup: Power Systems as on 1020815030 Run to begin at 9:00 AM ECDC overnight 2e-4 T D2. Gas setup: B-Top 6 psi D2 Hybrid Enabled (PG4) B-side lower 1 psi Ar Hybrid Enabled (PG1) B-side upper 10 psi D2 Hybrid DISABLED (PG2, for ECDC) C-Side 30 psi D2 Hybrid Enabled (PG3) J-Bottom as is, Hybrid DISABLED Enable the following gate valves: ECE,VUV,DNB RF Setup: Transmitters #2,3,4 in run-on by 7:00 Start with ten minutes of ECDC in D2 following RF conditioning ---------------------------------------------------------------------- Summary: The machine startup was very reproducible today. After a prefill tweak for shot 2 we had 29 discharges w/o any PCS changes to the startup. An unexplained fizzle on shot 29 was re-run on shot 30 without any PCS changes and it ran well. We began by allowing the TF to ramp down to 3.2T as was done on shot 1000915007; Catherine's previous ohmic h-mode run. We also set the Ip to 800 kA, consistent with that run. We were not able to get a nice, clean, extended h-mode as seen during the earlier run. Variations of target density, Bt, argon puff, or Ip were tried without great success. However, an extended period of elm-free and edaish/elmish h-modes were produced. These h-modes proved to be very reproducible, and we were able to fire the rf into the last one starting at 1 to 1.1 s, which also showed some peaking. Duds 00 Fizzles 02 Plasmas 29 Tests/Faults 02

Session Leader Comments
Aug 16 2002 09:10:58:390AM	1020816001	Catherine Fiore	Shot 1 : Fizzle
Aug 16 2002 09:40:53:300AM	1020816002	Catherine Fiore	Several good H-modes, although they keep dropping out. No VB data before next shot.
Aug 16 2002 10:00:22:810AM	1020816003	Catherine Fiore	Several good H-modes, although they keep dropping out. VB data was collected. There is a slight rise in the density peaking during the H-mode which started at 1.3 s.
Aug 16 2002 10:15:55:747AM	1020816004	Catherine Fiore	Three good H-modes, still dropping out, although the first one lasted 250 ms. There is an apparent ITB forming on the third H-mode.
Aug 16 2002 10:22:29:287AM	1020816005	Catherine Fiore	Commutation bank problem.
Aug 16 2002 10:44:20:390AM	1020816006	Catherine Fiore	Test
Aug 16 2002 11:00:02:877AM	1020816007	Catherine Fiore	Several H-modes. Unfortunately, the VB data could not be stored.
Aug 16 2002 11:21:51:917AM	1020816008	Catherine Fiore	Two longer lasting H-modes.
Aug 16 2002 11:33:35:260AM	1020816009	Catherine Fiore	Two longer lasting H-modes. VB data stored correctly. Not much sign of peaking on the density.
Aug 16 2002 12:35:34:940PM	1020816010	Catherine Fiore	Multiple H-modes , possible ITB at 1.3 s
Aug 16 2002 12:37:51:707PM	1020816011	Catherine Fiore	Two short H-modes , none after field increases
Aug 16 2002 12:40:05:460PM	1020816012	Catherine Fiore	One short H-modes , none after field increase except at current ramp down
Aug 16 2002 01:03:44:427PM	1020816013	Catherine Fiore	Multilple H-modes, it is possible that an ITB arose during the rf pulse, but the profiles will need to be checked more carefully.
Aug 16 2002 01:09:29:160PM	1020816014	Catherine Fiore	Multilple short H-modes, none long enought to build up an ITB
Aug 16 2002 01:10:58:583PM	1020816015	Catherine Fiore	No H-modes at all, but a good shot otherwise.
Aug 16 2002 01:19:56:300PM	1020816016	Catherine Fiore	Four H-modes, density peaking on the last one, beginning at 1.1 s
Aug 16 2002 01:36:41:397PM	1020816017	Catherine Fiore	Two good long H-modes. No significant density peaking.
Aug 16 2002 01:50:07:440PM	1020816018	Catherine Fiore	A single long EDA H-mode ITB starts building after 1.1s, drops out at 1.2, then continues growing through the remainder of the shot.
Aug 16 2002 02:04:47:757PM	1020816019	Catherine Fiore	Multiple H-modes, Density peaks, even with 200 kW rf on during last H-mode
Aug 16 2002 02:25:04:287PM	1020816020	Catherine Fiore	Multiple H-modes, Density starts to peak and stops, possibly starts to peak again with 200 kW rf.
Aug 16 2002 02:29:11:460PM	1020816021	Catherine Fiore	Multiple H-modes, Density is peaking on last H-mode, even with 200 kW of rf. We will raise the rf power on the next shot.
Aug 16 2002 02:42:41:863PM	1020816022	Catherine Fiore	Multiple H-modes, Density is peaking from 1.42 to 1.5 on last H-mode, 400 kW of rf on.
Aug 16 2002 02:56:34:327PM	1020816023	Catherine Fiore	Multiple H-modes, Density is peaking from 1.3 to 1.5 on last H-mode rising the full length of the 400 kW rf pulse.
Aug 16 2002 03:34:34:847PM	1020816024	Catherine Fiore	Multiple H-modes , Density is peaking from 1.3 to 1.5 on last H-mode rising the full length of the 600 kW rf pulse.
Aug 16 2002 03:33:52:470PM	1020816025	Catherine Fiore	Multiple H-modes , Density has slight peaking from 1.3 to 1.5 on last H-mode rising the full length of the 800 kW rf pulse.
Aug 16 2002 03:37:10:323PM	1020816026	Catherine Fiore	Multiple H-modes , Density no longer seems to be peaking from 1.3-1.5
Aug 16 2002 03:50:12:297PM	1020816027	Catherine Fiore	Multiple H-modes , The last one ends in an EN without significant peaking
Aug 16 2002 04:07:50:483PM	1020816028	Catherine Fiore	Multiple H-modes to begin with, one long one started just before the rf came on at 1.1 s and stayed on through the entire rf pulse. The density peaked up somewhat over the length of this last H-mode.
Aug 16 2002 04:08:05:107PM	1020816029	Catherine Fiore	Fizzle
Aug 16 2002 04:39:41:780PM	1020816030	Catherine Fiore	Multiple H-modes to begin with, one long one started just before the rf came on at 1.1 s and stayed on through the entire rf pulse. The density peaked up somewhat over the length of this last H-mode. -
Aug 16 2002 04:41:47:240PM	1020816031	Catherine Fiore	Multiple H-modes throughout, but a long H-mode was not sustained at the end as it had been in 28 and 30. We will try to get it to go a second time.
Aug 16 2002 04:56:15:690PM	1020816032	Catherine Fiore	Multiple H-modes throughout, but a long H-mode was sustained at the end as it had been in 28 and 30. The density was also peaking during this last H-mode. We will try high power for the last shot.
Aug 16 2002 05:10:19:470PM	1020816033	Catherine Fiore	Multiple H-modes throughout, but a long H-mode was sustained at the end. The rf power cut off repeatedly, so we didnt't get the sustained 2 MW we wanted. The modulation of the rf is affecting some of the outer VB channels so it is difficult to judge the peaking without a closer examination of the profiles.

Physics Operator Comments
Aug 16 2002 07:20:05:733AM		Jim Irby	Did coldstart: no errors rtnode -- data loaded, A matrix responds rtnode -- data loaded, M matrix responds rtnode -- data loaded, PID matrix responds RT_NODE Done 16-AUG-2002 07:17:47
Aug 16 2002 08:58:29:203AM		Jim Irby	PCS: TF current to 90kA from 0.50 to 0.805 s (3.2T) then back up to 128kA (4.6T) Ip to 800 kA
Aug 16 2002 09:09:51:467AM	1020816001	Jim Irby	Fizzle Looks like too much gas
Aug 16 2002 09:30:56:413AM	1020816002	Jim Irby	Reduced gas puff by 8 ms Nice plasma: several h-modes TF down to 3.36 T, a little high
Aug 16 2002 09:45:35:383AM	1020816003	Jim Irby	Reduced TF current request to 88kA at 0.5 s; started back up to 4.6T at little later at 0.825 s. Plasma: More h-modes Need bigger tweak in TF to get field down.
Aug 16 2002 10:06:09:703AM	1020816004	Jim Irby	Dropped prefill by another 2 ms Dropped density request from 8 to 7e19/m^2 Plasma: Good 1st h-mode; lasted a little beyond field ramp-up time
Aug 16 2002 10:16:38:857AM	1020816005	Jim Irby	Cut argon puff by 60% or so --- see if Prad or h-mode changes Problem with EF1 commutation charging supply ---- ran through cycle with no power
Aug 16 2002 10:39:12:087AM	1020816006	Jim Irby	Dropped nl04 request to 6e19/m^2 until 0.6 s This will be an EF1 commutation bank test Enabled gas and allowed DNB to fire EF1 banks charged okay
Aug 16 2002 11:00:59:923AM	1020816007	Jim Irby	Nothing found on EF1 bank --- try for plasma This shot will have very little argon and reduced nl04 request Nice plasma --- no control over target density however PO changed argon and nl04 in seg #2 not #3! --- so no change in either
Aug 16 2002 11:16:06:207AM	1020816008	Jim Irby	Several PCS changes in segment #3: argon reduced by 20 ms nl04 to 6e19/m2 request min TF current from 88kA to 100kA H-mode lasts a little longer
Aug 16 2002 11:38:47:310AM	1020816009	Jim Irby	gave John 10ms more argon than at start of run Asked for 200 kW of rf from j-port from 1.3 to 1.5 s Plasma: Got some rf, but not well matched yet: 140 kW
Aug 16 2002 11:50:20:370AM	1020816010	Jim Irby	Extended TF flattop to 1.5 s rf delayed somewhat to 1.4 s Plasma --- got 200 kW h-modes not as good
Aug 16 2002 11:59:45:617AM	1020816011	Jim Irby	Dropped nl04 request a little Reduced argon by 10 ms Plasma but not much better --- rf generates late h-mode
Aug 16 2002 12:12:10:070PM	1020816012	Jim Irby	Ip from 800 to 900 kA Only 1 h-mode now --- got the higher Ip though H-Mode is very solid elm-free discharge --- density too low?
Aug 16 2002 12:25:08:583PM	1020816013	Jim Irby	Ip back down to 800 kA Nl04 request back up to 8e19/m^2 Plasma --- Definite improvement
Aug 16 2002 12:52:09:083PM	1020816014	Jim Irby	Raised density request to 9e19/m^2 --- try to reduce elm-free period More extended h-modes --- but still not staying in the whole shot --- first h-mode later
Aug 16 2002 12:57:01:317PM	1020816015	Jim Irby	nl04 request back to 7e19/m^2 min TF now 4.6T --- we were getting H-Modes at the higher field anyway Plasma, but no h-mode ---- theory incorrect
Aug 16 2002 01:21:55:723PM	1020816015	Jim Irby	Ramping TF down to 3.2 again (90kA) H-modes but very elm-free like again
Aug 16 2002 01:32:59:020PM	1020816017	Jim Irby	TF current from 90 to 85 kA Nl04 to 8e19/m^2 1st h-mode lasts longer --- peak density is also higher
Aug 16 2002 01:45:20:350PM	1020816018	Jim Irby	NL04 request to 9e19/m^2 Much better --- extended h-mode
Aug 16 2002 02:10:38:803PM	1020816019	Jim Irby	NL04 request to 1e20/m^2 rf turn-on at 1.3 s Two elm-free h-modes
Aug 16 2002 02:19:25:927PM	1020816020	Jim Irby	NLO4 back to 8e19/m^2 several h-modes --- still not as good as shot 18
Aug 16 2002 02:27:58:647PM	1020816021	Jim Irby	repeat pretty close to shot 20 --- last h-mode lasted a little longer
Aug 16 2002 02:48:17:630PM	1020816022	Jim Irby	increased the rf power to 400 kW rf was at 400kW but a little late rf may have actually extended the h-mode to 1.5 s
Aug 16 2002 02:51:46:037PM	1020816023	Jim Irby	rf on at 1.3 s no clear effect seen on h-mode
Aug 16 2002 03:03:49:977PM	1020816024	Jim Irby	rf to 600 kW
Aug 16 2002 03:32:24:840PM	1020816026	Jim Irby	rf to 1 MW some rf faults from 1.3 to 1.4 s
Aug 16 2002 03:41:56:247PM	1020816027	Jim Irby	No rf last h-mode is shorter
Aug 16 2002 03:59:18:327PM	1020816028	Jim Irby	rf start at 1.1 s and 600kW last h-mode started earlier (before rf)? rf seems to extend it.
Aug 16 2002 04:07:25:000PM	1020816029	Jim Irby	more rf fizzle
Aug 16 2002 04:21:42:533PM	1020816030	Jim Irby	try again plasma
Aug 16 2002 04:33:55:000PM	1020816031	Jim Irby	200 kW rf argon puff increased by 5 ms argon MAY have changed the h-mode character
Aug 16 2002 04:47:24:943PM	1020816032	Jim Irby	decreased argon puff by 20 ms --- sorry John good h-mode again
Aug 16 2002 05:07:21:490PM	1020816033	Jim Irby	rf to 2 MW plasma rf was faulting

Engineering Operator Comments
Shot	Time	Type	Status	Comment
1	09:00:57:113AM	Plasma	Ok
2	09:19:56:430AM	Plasma	Ok
3	09:39:48:203AM	Plasma	Ok
4	09:59:35:947AM	Plasma	Ok
5	10:12:46:367AM	Plasma	Bad	ef1l cap bank did not charge
6	10:36:42:443AM	Test	Ok	ef1 cap bank charge test
7	10:47:24:953AM	Plasma	Ok
8	11:02:29:380AM	Plasma	Ok
9	11:21:08:993AM	Plasma	Ok
10	11:39:54:233AM	Plasma	Ok
11	11:52:45:187AM	Plasma	Ok
12	12:05:49:640PM	Plasma	Ok
13	12:18:55:763PM	Plasma	Ok
14	12:32:50:983PM	Plasma	Ok
15	12:53:54:333PM	Plasma	Ok
16	01:06:52:473PM	Plasma	Ok
17	01:23:48:660PM	Plasma	Ok
18	01:36:37:380PM	Plasma	Ok
19	01:51:42:787PM	Plasma	Ok
20	02:04:39:053PM	Plasma	Ok
21	02:17:34:427PM	Plasma	Ok
22	02:30:21:817PM	Plasma	Ok
23	02:43:13:160PM	Plasma	Ok
24	02:56:18:560PM	Plasma	Ok
25	03:09:10:713PM	Plasma	Ok
26	03:22:04:350PM	Plasma	Ok
27	03:34:59:880PM	Plasma	Ok
28	03:50:34:247PM	Plasma	Ok
29	04:03:52:020PM	Plasma	Ok
30	04:16:42:763PM	Plasma	Ok
31	04:30:05:753PM	Plasma	Ok
32	04:43:03:607PM	Plasma	Ok
33	04:56:02:990PM	Plasma	Ok