Alcator C-Mod Run 1021022 Information

Back to runs

Miniproposals
Miniproposal:324a
Date Filed:10/10/2003
Title:ITB Formation with TwoÐFrequency ICRF in Optimized Shear Plasmas with IP Ramp
First Author:Miklos Porkolab
Session Leader:Miklos Porkolab (shots 1-31)
Miniproposal:326
Date Filed: 8/26/2002
Title:D, E, and J-port Antenna Evaluation and Comparison
First Author:Steve Wukitch
Session Leader:Steve Wukitch (shots 1-31)

Operators
Session leader(s):Steve Wukitch,Miklos Porkolab
Physics operator(s):Earl Marmar
Engineering operator(s): Unknown

Engineering Operator Run Comment
MP#326 RF Antenna Evaluation & MP#324A Ip ramp studies; SL: Wukitch & SL

Session Leader Plans

Physics Operators Plans

Session Leader Summaries
Entered: Jul 7 2004 03:49:31:383PM
Author: To Be Determined
From: DAIGLE::PORKOLAB
Subj: Session Leader Summary 1021022

A good and successfull day to start MP 324:
"ITB formation with Two-Frequency ICRF in optimized Shear Plasmas with Ip
Ramp."
We began with a similar shot to 960223047 from 1996, except started the field
at 4.6 T with off axis heating at 80 MHz (D and E port antennas). The objective
was to delay sawtoothing by application of high-field side off-axis heating.
Good shots during early ramp started on shot 07, at 1.4 MW with D and E port
antennas together. Further objective was to form RS plasmas which could
then be heated with 70 MHz on axis. On shot 11, the B field was reduced to
4.5T to move the resonance further out where more reliable ITBs were obtained
in the past (although in the present run the density was too low to
have EDA H modes and/or ITBs). In shot 14 we were successful in injecting 0.8
MW from the J port antenna at 0.6 to 1 1sec, for tuning purposes (and got Elm
free H mode with J antenna). Continued to inject 1.5 MW from E and D early on,
by stepping up the power from 1.0 to 1.5 MW, typically after 0.12 sec.
Typically we ramped the current up to 0.8 MA, although in shot 14 we ramped to
1.0 MA. However, ramping to 1.0 MA did not make any difference in delaying
sawteeth, so kept ramping up to 0.8 MA only in the remaining of the run.
In shots 18 and 19 we delayed sawteeth to 0.24 sec, and in shot 20 sawteeth
were delayed to 0.293 sec, all with 2.0 MW of E+D power at 4.5T. J port (70MHz
) had difficulty with cross talk and could not inject it. In shot 21 sawteeth
were delayed to 0.298 sec, with E+D ports only (similar results in 23, 24). In
shots with early hard X-rays(shot 22) sawteeth came in early, hence need to
be careful with breakdown and avoid runaways. Shot 25 was interesting, with
E+D+J ports all firing together, injected 3.0 MW, got H mode, perhaps with
some kind of large ELMs. This kind of shot could be explored in the future.
Shot 27 attempted to see if high density operation would help: doubled density
, however sawteeth came in early since temperature was low (Te less than 2.0
keV). Hence did not continue this approach. Instead, we raised the field to 5.4
T on shot 28 and beyond, and shots 29 to 31 produced very interesting results.
In particular, on shot 31 we got a total power of 3.3 MW, (D+E+J) and a
central Te=5.0 keV, with sawteeth delayed to 0.27 second. This should form a
good target plasma for next day to further increase the power and begin
profile measurements, including toroidal rotation, MSE and Li pellet
injection. In sum, once both on and off axis power is injected successfully,
either 5.3T or 4.5T scenarios can be used for RS plasma experiments.
One more thing we could try is to lower the plasma current to see if we could
establish higher beta-N plasmas to increase the bootstrap current.

Physics Operator Summaries
Entered: Jul 7 2004 04:37:16:613PM
Author: To Be Determined
Physop run summary 1021022

Run Plan and Engineering Setup for Tues 22 Oct 2002

PO: Marmar

MP#326 RF Antenna Evaluation (~5 shots) SL: Wukitch
MP#324A Ip ramp studies SL: Porkolab

Engineering Setup
-----------------
Power Systems as on 1021011001

Overnight bake at 60 C, with ECDC in D2 at 2e-4 torr, off by 7:00AM

Run to begin at 9:00 AM

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, assuming no vacuum problems:
ECE,VUV,DNB

RF Setup: #1,2 and 3 in run-on by 7:00 am

Run Plan:
--------------

Start with a standard 5.3 T shot, possibly with ramp-down to ~4.6 T, to test
J-Port in the dipole configuration (70 MHz).

After that, begin discharge development for MP324A, which requires
breakdown at ~4.6 T, with off-axis ICRF heating (80 MHz) as early as possible
in the discharge to form an ITB with reverse shear, followed by on-axis
heating at 70 MHz.

Results:
___________________

The run went well from the physop point of view. J-port was having some control
issues early, so after only 1 shot at 5.4 tesla, we switched to 4.6 T for
MP324A. Startup at 4.6 T proved to be easy; there were some fizzles, but they
appeared to be due to gas, not fields. The only wirehead change made for the lower field
startup, other than the TF current programming, was to make the EF1U&L
precharge current slightly more negative (by 90 amp for the 4.5 T, -123.8 kA TF
current case). There were many shots with very early RF, including both on-axis and
off-axis power. At the end of the run, we went back to 5.4 T, with D&E on-axis.
The last shot, #31, was also 5.4 T with 2 MW on-axis from D&E and 1 MW from J
off-axis on the low-field side.

There were several very early H-Modes. Shot 25 had an H-alpha signal that looked
suspiciously similar to type I ELMS.

The run was delayed slightly at the beginning because of an alternator low oil
alert. Other than that, there were no power system or data system problems
today.

Scorecard:

Plasmas 26
Fizzles 4
Cycle test 1

Total cycles 31

Session Leader Comments
Oct 22 2002 10:47:28:753AM1021022004Miklos PorkolabGood shot, with RF at 1.5 MW, late in shot, at 0.6 to 1.5 sec.
Will move RF to rearlier times to heat during ramp.
Oct 22 2002 10:57:51:107AM1021022005Miklos PorkolabOhmic shot, no RF.
Oct 22 2002 11:08:35:980AM1021022006Miklos Porkolab
FIzzle; no RF target.
Oct 22 2002 11:35:07:743AM1021022007Miklos PorkolabGood shot. Coupled in 1.5 MW strating at 0.11 s.
Sawteeth start at 0.21 sec.
Oct 22 2002 11:37:03:497AM1021022008Miklos PorkolabMove RF earlier. Fizzle.
Oct 22 2002 11:59:08:583AM1021022009Miklos Porkolab
Good shot, couple 1.o MW early on.
Sawteeth are still not delayed much.
There is some good heating before sawteeth appear but
it is transient.
Oct 22 2002 12:21:14:890PM1021022010Miklos PorkolabGood shot, start with 1.0 MW around 0.07 sec, followed by rampup of the
RF power to 1.5MW around 0.15 sec. Sawteeth come in a little early, around 0.20 sec.
Magnetic field still at 4.65T.
Oct 22 2002 12:47:07:937PM1021022011Miklos PorkolabGood shot. Bt=4.50T. Power ramped from 1.0MW to 1.5 MW
at 0.15 sec. MHD occurs at 0.22 through 0.238 sec, at which time sawteeth come in
and the temperature crashes. Interestingly, sawteeth come in later at 4.50T
than in previous shots (sawteeth at 0.22sec at 4.65s).
Oct 22 2002 12:50:59:363PM1021022012Miklos Porkolab
Same shot type as shot 11, but now try to couple J port power at 0.7sec
in the flat-top phase. Will try to move J-port power earlier once coupling is achieved.
D and E ports couple as before.
Oct 22 2002 12:59:58:500PM1021022013Miklos Porkolab
Same target shot as before, but now J port antenna couples
200kW at 0.6-0.8 sec. Good approach. Will increase J port power toward
1 MW on next shot, while maintaining the E and D port power as before (1.0-1.5MW)
stepwise.
Oct 22 2002 01:17:55:643PM1021022014Miklos Porkolab
J port power successful, power at 0.8MW injected at 0.6 to 1.1 sec,
getting Elm free H mode. D and E OK as before. Current ramped to 1.0 MA,
but this did not help in the early phase.
Oct 22 2002 01:32:13:300PM1021022015Miklos Porkolab
Target plasma similar as before, but sawteeth come in earlier
(at 0.20 sec), no MHD. J port did not couple, tuning problem.
Will repeat shot.
Oct 22 2002 02:08:41:407PM1021022016Miklos Porkolab
Raised total D and E port power to 2.0 MW at 0.16 sec. Successful.
Not much difference from previous shot at 1.5 MW. J port fired
at 0.11sec, but tripped early on. Did manage to couple 0.5MW.
Oct 22 2002 02:06:30:763PM1021022017Miklos PorkolabRaised D and E port power to 2.0 MW earlier.
Coupled in 0.8MW from J port, starrting at 0.1 sec, then went into H mode
at 0.18 sec. Total power up to 3.0 MW. E+D is coupling 2.0 MW.
Sawteeth still coming in at 0.22 sec.
Oct 22 2002 02:18:16:253PM1021022018Miklos Porkolab
D +E power 2.0 MW starting at 0.125 sec. Sawteeth delayed to 0.24 sec;
perhaps the most delay yet ? Stored energy is up to 35000kJ.
J port tripped out, no central heating. Repeat again, move to high power (2.0MW)
earlier on next shot, to see if sawteeth are delayed further.
Oct 22 2002 02:37:45:683PM1021022019Miklos Porkolab
Excellent shot. D+E coupled in 2.0 MW at 0.1 sec. J port tripped.
However, the sawteeth got delayed to 0.28 second from 0.24 sec
from the previous shot.
Oct 22 2002 02:45:48:230PM1021022020Miklos Porkolab
Excellent shot, 2.0 MW starting at 0.1 sec, sawteeth got delayed to 0.293 second.
J port was tested at a much later time to resolve RF problems.
Oct 22 2002 03:00:47:477PM1021022021Miklos Porkolab
Excellent shot, early 2.0 MW RF, sawtooth delayed to 0.298 sec.
No J port power.
Oct 22 2002 03:17:00:040PM1021022022Miklos PorkolabMove full 2 MW (D+E) to 0.050 sec.
Got J port on at the same time (2.8MW toatl power).
However, hard x-rays early on (Earl) brought the sawteeth back to 0.22 sec.
Oct 22 2002 03:29:22:297PM1021022023Miklos Porkolab
D+E=2.0 MW early on. J port tripped . Sawteeth delayed to 0.293 sec
as before. No runaways.
Oct 22 2002 03:42:13:993PM1021022024Miklos Porkolab
J port did not fire. D+E is at 2.0 MW, no runaways,
sawteeth come in at 0.29 sec.
Oct 22 2002 05:53:54:590PM1021022025Miklos Porkolab Got H mode early on, with D+E+ J antenna. Sawteeth come in at 0.23 sec.
Very interesting shot. Got type I Elms ???

Oct 22 2002 04:11:02:080PM1021022026Miklos Porkolab
D+E at 2.5 MW, RF tripped early then started at 0.07 sec.
Sawteeth came in early, at 0.23 sec.
Will try to raise the density on the next shot to see if we can get ITBs.

Oct 22 2002 04:41:12:623PM1021022027Miklos Porkolab
Higher density shot; lower T_e, sawteeth come in early at 0.22 sec.
Zeff is above 2.0 in the early phase. (?). Field is still 4.5T.
T_e is below 2.0 keV. This is not a good approach to slow down current
penetration. Next shot we raise the field to 5.3T and lower density.
Oct 22 2002 04:46:42:947PM1021022028Miklos PorkolabRaised field to 5.3 T. Fizzle. Too high density.
Oct 22 2002 05:51:18:757PM1021022029Miklos PorkolabGood shot. Still a little high density, Prf=2.0 MW, D+E ports.
T_e=3.6keV before sawteeth come in around 0.26sec.
B_T=5.4T. Lower density on next shot and add J port antenna.
Oct 22 2002 05:47:37:173PM1021022030Miklos Porkolab2.0 MW, 5.4 T, lower density, but sawteeth come in early, still, at
0.26. There were runaways. However, Te=4.0 keV just before sawteeth
start and nl_04=0.7^20. Getting very close to that in 1996.
Oct 22 2002 05:42:20:193PM1021022031Miklos PorkolabExcellent shot, power at 3.3 MW, nl_04=0.6, T_e=5.0 keV.
B_T=5.4T, central heating with E and D port, off axis heating
with J port on the low field side. Sawteeth delayed until 0.27sec.
Continue here tomorrow.

Physics Operator Comments
Oct 22 2002 09:02:21:710AMEarl Marmar
Run Plan and Engineering Setup for Tues 22 Oct 2002

PO: Marmar

MP#326 RF Antenna Evaluation (~5 shots) SL: Wukitch
MP#324A Ip ramp studies SL: Porkolab

Engineering Setup
-----------------
Power Systems as on 1021011001

Overnight bake at 60 C, with ECDC in D2 at 2e-4 torr, off by 7:00AM

Run to begin at 9:00 AM

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, assuming no vacuum problems:
ECE,VUV,DNB

RF Setup: #1,2 and 3 in run-on by 7:00 am

Run Plan:
--------------

Start with a standard 5.3 T shot, possibly with ramp-down to ~4.6 T, to test
J-Port in the dipole configuration (70 MHz).

After that, begin discharge development for MP324A, which requires
breakdown at ~4.6 T, with off-axis ICRF heating (80 MHz) as early as possible
in the discharge to form an ITB with reverse shear, followed by on-axis
heating at 70 MHz.
Oct 22 2002 09:02:34:367AM1021022001Earl Marmartest
Oct 22 2002 09:38:26:203AM1021022002Earl Marmarload from 1021018001

TF to -150kA straight across

plasma; no RF
Oct 22 2002 10:16:13:433AM1021022003Earl Marmarattempt at 4.6 T startup

TF -128 kA straight across

EF1 U&L 80 kA more negative at t=0

fizzle; fields look ok
Oct 22 2002 10:34:56:317AM1021022004Earl Marmarreduce PG4 prepuff to 29 msec (from 32)

plasma; somewhat late breakdown

Oct 22 2002 10:54:12:277AM1021022005Earl Marmarreduce PG4 prepuff 1 msec (to 28 msec)

increase early dI/dt slightly (0.8 MA at 0.2 s)

plasma; earlier breakdown; no RF

first sawtooth at 0.234 s
Oct 22 2002 11:04:10:990AM1021022006Earl Marmarno pcs changes

fizzle
Oct 22 2002 11:19:49:867AM1021022007Earl Marmarlower PG4 prepuff to 25 ms (from 28 ms)

plasma

1.4 MW RF (D+E) starting at about 0.1 s

first sawtooth at 0.216 s
Oct 22 2002 11:36:07:887AM1021022008Earl Marmarno pcs changes

fizzle
Oct 22 2002 11:54:48:673AM1021022009Earl Marmarpg4 prepuff to 22 ms (from 25)

nl_04 prog to 7e19 (from 8e19)

fizzle detector start moved to 60 ms (from 80 ms)

plasma
Oct 22 2002 12:02:14:010PM1021022010Earl Marmarreduce TF slightly (to 123.8 kA)

plasma

early hards
Oct 22 2002 12:41:04:837PM1021022011Earl Marmarpg4 prepuff to 24 ms (from 22 ms)

TF to -123.8kA straight across
EF1U&L to -6090 (from -6080)

plasma
Oct 22 2002 12:41:23:400PM1021022012Earl Marmarno pcs changes

plasma; early hards
Oct 22 2002 12:57:45:573PM1021022013Earl Marmaradd 2 msec to pg4 prepuff (now 26 ms)

plasma
Oct 22 2002 01:13:20:403PM1021022014Earl Marmarkeep the current ramping up, to 1 MA at 0.25s

plasma; disrupt at 1.56 s
Oct 22 2002 01:45:18:893PM1021022015Earl Marmarremove current ramp (back to programming from shot 13)

plasma
Oct 22 2002 01:45:35:847PM1021022016Earl Marmarno pcs changes

plasma
Oct 22 2002 01:58:15:280PM1021022017Earl Marmarno pcs changes

plasma

very early H-Mode (0.18 seconds)
Oct 22 2002 02:06:41:763PM1021022018Earl Marmarno pcs changes

plasma; no H-mode this time
Oct 22 2002 02:22:00:543PM1021022019Earl Marmaradd 1 ms to pg4 prepuff (DNB gate valve opening for the first time today)

plasma; some early hards
Oct 22 2002 02:55:35:310PM1021022020Earl Marmaradd 1 ms to pg4 prepuff

plasma
Oct 22 2002 02:55:47:763PM1021022021Earl Marmarno pcs changes

plasma
Oct 22 2002 03:06:46:847PM1021022022Earl Marmarfizzle detector on at 0.04 s (move RF earlier)

plasma; early hards; sawteeth start earlier
Oct 22 2002 03:24:34:490PM1021022023Earl Marmaradd 2 ms to pg4 prepuff (now 30 ms)

plasma; no hards
Oct 22 2002 03:40:44:960PM1021022024Earl Marmarno pcs changes

plasma
Oct 22 2002 03:52:29:420PM1021022025Earl Marmarno pcs changes

plasma
Oct 22 2002 04:06:02:727PM1021022026Earl Marmarno pcs changes

plasma
Oct 22 2002 04:23:24:090PM1021022027Earl Marmarincrease programmed early density

plasma
Oct 22 2002 04:35:40:690PM1021022028Earl Marmarback to 5.4 T (-150 kA on TF)

EF1 U&L back to -6000 A (from -6090)

reduce nl_04 prog to 7e19

fizzle
Oct 22 2002 05:03:58:590PM1021022029Earl Marmarreduce pg4 prepuff by 3 ms (now 27 ms)

plasma
Oct 22 2002 05:06:19:670PM1021022030Earl Marmarlower nl_04 prog

plasma; some early hards
Oct 22 2002 05:22:12:700PM1021022031Earl Marmaradd 2 ms to pg4 prepuff; lower pg3 voltage programming

plasma; still early hards

over 3 MW RF, Te approaches 5 keV

Engineering Operator Comments
ShotTimeTypeStatusComment
107:09:37:343AMTestOkData system and Gas test
209:26:41:660AMPlasmaOk
310:10:15:380AMPlasmaOk
410:24:31:430AMPlasmaOk
510:44:17:357AMPlasmaOk
610:58:17:450AMPlasmaOk
711:11:56:373AMPlasmaOk
811:25:54:517AMPlasmaOk
911:40:42:330AMPlasmaOk
1011:57:38:490AMPlasmaOk
1112:15:35:260PMPlasmaOk
1212:30:46:543PMPlasmaOk
1312:46:06:140PMPlasmaOk
1401:00:43:780PMPlasmaOk
1501:16:07:890PMPlasmaOk
1601:30:29:610PMPlasmaOk
1701:46:31:287PMPlasmaOk
1802:00:53:380PMPlasmaOk
1902:15:26:203PMPlasmaOk
2002:31:33:017PMPlasmaOk
2102:45:12:213PMPlasmaOk
2202:58:57:707PMPlasmaOk
2303:12:46:047PMPlasmaOk
2403:27:32:717PMPlasmaOk
2503:41:36:320PMPlasmaOk
2603:57:08:460PMPlasmaOk
2704:11:42:050PMPlasmaOk
2804:27:25:737PMPlasmaOk
2904:40:34:543PMPlasmaOk
3004:53:51:727PMPlasmaOk
3105:07:04:407PMPlasmaOk