Alcator C-Mod Run 1050727 Information

Back to runs

Miniproposals
Miniproposal:425
Date Filed: 5/13/2005
Title:Toroidal rotation in dimensionally similar discharges with no momentum input
First Author:John Degrassie
Session Leader:John Degrassie (shots 1-34)
Session Leader:John Rice (shots 4-34)

Operators
Session leader(s):John Degrassie,John Rice
Physics operator(s):
Engineering operator(s):Gary Dekow

Engineering Operator Run Comment
MP 425 EO Pierson PO Parker SL Rice, Degrassie

Session Leader Plans
Entered: Jul 26 2005 12:58:36:853PM
Author: John Degrassie
SESSION LEADER PLAN
1050727***
MP 425
â??Toroidal rotation in dimensionally similar discharges with no momentum inputâ??

SL: J.S. deGrassie, J.E. Rice

The goal is to run C-MOD discharges with dimensionless similarity to discharges run in DIII-D, and measure the toroidal rotation velocity, thereby establishing whether non-driven rotation can be described in some way by the dimensionless parameters. Ideally, these are to be H-mode discharges as much in steady state as possible.

The first day was 1050706, at 6T. We found that we must relax the shaping demands back to standard C-MOD.

Today will start at 3.75 T, H-minority (50MHz). Attempt to obtain desired density and temperature at given q95, with available â??knobsâ?? ( RF power, target density, gas?). The Ip values are approximate guesses. Matching q95 is the goal.

1. Replicate DIII-D 118190.01850 scaled to C-MOD:
Bt= 3.75 T q95= 4.9, Ip~ 0.57MA, n= 2.1^20 (n/nG ~ 0.55), T_0= 1.65 keV

2. Modify Beta and q95, with product the same as case 1.
Bt= 3.75 T q95= 3.7, Ip~ 0.76, n=2.8^20 (n/nG ~ 0.55), T_0= 1.65 keV

3. Modify Beta and q95, with product the same as case 1.
Bt= 3.75 T q95= 6.5, Ip~ 0.43, n=1.6^20 (n/nG ~ 0.55), T_0= 1.65 keV

************
4. Attempt off-axis 3He minority to match parameters (except rho*) attempted at 6T, (with H minority at 80MHz). If it is clear this will not be possible, move on. 50MHz, â??heatingâ?? best.

Bt= 5.63 T q95= 4.9, Ip~ 0.86, n= 3.5^20 (n/nG ~ 0.62), T_0= 2.15 keV

************
5. Return to H minority. Vary collisionality.
Bt= 3.6 T, q95= 4.9, Ip~ 0.55, n= 2.4^20 (n/nG~0.66), T_0= 1.3

6. Vary beta
Bt= 3.6 T, q95= 4.9, Ip~ 0.55, n= 1.3^20 (n/nG~0.36), T_0= 1.3

If there should be more time (!), we will have some q95 variations planned.


Physics Operators Plans
Entered: Jul 26 2005 02:48:08:823PM
Author: Ron Parker
PO Plan for Wednesday, 27 July 2005

MP 425: Toroidal rotation in dimensionally similar discharges with no momentum input

SL's: J.S. deGrassie, J.E.Rice
PO: R. Parker

Engineering setup as on 1050726001

No Overnight ECDC.

Run begins at 09:00 and ends at 17:00

A-coil configuration: normal [+Dtop -Dbot -Jtop +Jbot] and 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 15 psi He3, disabled (PG2)
fill B-main with 40 psi D2 Hybrid enabled (PG3)

Enable the following: ECE and VUV gate valves, Z-bolo shutters

ICRF Setup: transmitters in run-on at 8:30

Run Plan: See SL Run Plan.


Session Leader Summaries
Entered: Jul 27 2005 05:27:55:327PM
Author: John Degrassie
A good day. A number of conditions were achieved with reasonable
matches to the desired dimensionless targets, and for this SL the
CMOD parameter space is more clear. All the shots from
07 onward will be useful for rotation studies (Ar first introduced
on 07 according to my notes). The 'matched' shots to the PLAN:
(Beta and nu values as in the MP; only target values are listed,
not the precise values achieved since these will take a closer
look into the data to ascertain.)
1050727010: Case 1. q95=4.9 BT= 3.75 (H)50MHz beta=2.4, nu=1.7
017: Case 2. q95=3.7 BT= 3.75 " 3.2, 2.3
020: Case 3. q95=6.5 BT= 3.75 " 1.8, 1.3
028: Case 4. q95=4.9 BT= 5.63 (3He)50MHz 2.4, 1.7
(H)80MHz
Given the time of day, and the data obtained, rather than continue
to Case 5 of the PLAN, we did two added Cases, equivalent to the
q variation done in Case 2 and Case 3 above.
1050727030: Case 3' q95=6.5 BT= 5.63 both? 1.8, 1.3
34: Case 2' q95=3.7 BT= 5.63 only one 3.2 2.3
It might be difficult to achieve the needed density for Case 2' in
any event, given more time.

Physics Operator Summaries
Entered: Jul 27 2005 04:51:25:483PM
Author: Ron Parker
Machine ran reasonably well today and much but not all of the run plan was accomplished.

The only machine problem was a crowbar of the OH2 L power supply which caused a disruption on shot 26. No reason was found for the crowbar and it did not recur for the remainder of the run.

In summary, we ran 34 shots today with one disruption, as mentioned above, 2 unexplained duds and one engineerng test shot that was run after the OH2 L crowbar. The remaining 30 shots ran as programmed and hopefully produced useful data.

Session Leader Comments
Jul 27 2005 09:41:56:770AM1050727001John Rice0.55 MA, 3.9 T
ne=0.8
1.5 MW ICRF
ELM-free H-mode
Jul 27 2005 09:43:02:180AM1050727002John Rice0.55 MA, 3.9 T
ne=0.8
1.5 MW ICRF
ELM-free H-mode
Jul 27 2005 09:43:14:537AM1050727003John Ricedud
Jul 27 2005 09:45:24:850AM1050727004John Rice0.5 MA, 3.8 T
ne=0.9
ELM-free H-modes
Jul 27 2005 10:09:35:007AM1050727005John Rice0.5 MA, 3.8 T
ne=1.1 target
EDA H-mode
Jul 27 2005 10:20:12:710AM1050727006John Rice0.5 MA, 3.8 T
ne=1.1 target
EDA H-mode
Jul 27 2005 10:22:21:677AM1050727007John Rice0.5 MA, 3.8 T
ne=1.1 target
Ar on
not steady H-mode
Jul 27 2005 10:35:09:600AM1050727008John Rice0.5 MA, 3.8 T
ne=1.1 target
Ar on
not steady H-mode
Jul 27 2005 10:48:52:427AM1050727009John Rice0.5 MA, 3.8 T
ne=1.1 target
reduce Ar
quasi steady H-mode
Jul 27 2005 11:12:48:867AM1050727010John Rice0.5 MA, 3.8 T
ne=1.0 target
reduce Ar
good EDA H-mode
Jul 27 2005 11:13:35:020AM1050727010John DegrassieGood shot for Case 1. today. Beta dithers between [2.,2.7] (target 2.4)
and nu between [1.7,3.1] (target 1.7). Shots 7-10 (with Ar puff) have
been valuable, with a useful beta, but with some tradeoff with higher
density and lower temperature (higher nu).
Jul 27 2005 11:20:21:867AM1050727011John Rice0.75 MA, 3.8 T
ne=1.0 target
ELM-free H-modes
Jul 27 2005 11:32:01:147AM1050727012John Rice0.75 MA, 3.8 T
ne=1.2 target, 2.5 steady
EDA H-mode
Jul 27 2005 11:45:00:333AM1050727013John Rice0.75 MA, 3.8 T
ne=1.1 target, 2.5 steady
EDA H-mode
Jul 27 2005 12:08:38:757PM1050727015John Rice0.75 MA, 3.8 T
ne=1.3 target, 2.6 steady
EDA H-mode
Jul 27 2005 12:23:53:637PM1050727016John Rice0.75 MA, 3.8 T
ne=1.2 target, 2.5 steady
EDA H-mode
Jul 27 2005 12:38:15:327PM1050727017John Rice0.75 MA, 3.8 T
ne=1.2 target, 2.7 steady
good EDA H-mode
Jul 27 2005 12:42:26:450PM1050727017John DegrassieTake this shot for case 2 today. Beta [2.5,3.5] (target 3.2),
nu [3.,6.] (target 2.3).
Now go to lower Ip, target q95= 6.5 (Ip~0.43MA), ne=1.6, te=1.65
Jul 27 2005 12:49:36:310PM1050727018John Rice0.45 MA, 3.8 T
ne=0.9 target, 1.6 steady
EDA H-mode
Jul 27 2005 01:05:03:513PM1050727019John Rice0.41 MA, 3.8 T
ne=0.9 target, 1.4 steady
EDA H-mode
Jul 27 2005 01:29:27:797PM1050727020John DegrassieTake shots 19 and 20 as closest to case 3 today.
Beta [1.5,2.2] (target 1.8), nu [.7,3] (target 1.3)

Now go to case 4: 3He minority 5.63T q95= 4.9
Ip~ 0.86MA. n= 3.5 Te= 2.15
Jul 27 2005 02:08:32:437PM1050727022John Rice0.86 MA, 5.6 T
ne=1.5 target, 1.4 steady
L-mode
Jul 27 2005 02:28:14:420PM1050727023John Rice0.8 MA, 5.6 T
ne=1.5 target, 1.4 steady
late H-mode
Jul 27 2005 02:29:52:047PM1050727023John Ricedud
Jul 27 2005 02:45:48:467PM1050727024John Rice0.8 MA, 5.6 T
ne target 1.5
ELM-free H-modes
Jul 27 2005 02:45:57:653PM1050727025John Rice0.8 MA, 5.6 T
ne target 1.5
ELM-free H-modes
Jul 27 2005 02:56:28:153PM1050727026John Ricedisruption
Jul 27 2005 03:38:18:857PM1050727027John RiceOH test
Jul 27 2005 03:56:00:733PM1050727028John Rice0.8 MA, 5.6 T
ne target 1.7, 2.9 steady
good EDA H-mode
Jul 27 2005 04:02:24:250PM1050727028John DegrassieUse shot 28 for case 4 today
Beta [1.4,2.3] (target 2.4)
nu [1.5,3.3] (target 1.7)

Given time of day, and what we have learned so far:
Rather than going to step 5 on the plan, Stay at
this BT and lower Ip (raise q) with Beta*q95 constant
in the same step as done between case 1 and case 2 today.
Goal: q95= 6.5 (Ip~0.6) n= 2.7 Te= 2.15
Jul 27 2005 03:58:23:450PM1050727029John Rice0.6 MA, 5.6 T
marfe
strange shot
Jul 27 2005 04:10:36:500PM1050727030John Rice0.6 MA, 5.6 T
nebar of 2.1
good EDA H-mode
Jul 27 2005 04:19:57:030PM1050727030John DegrassieShot 30 is a good, quick match to the goal:
Beta [1,2] (target 1.8) nu [1.2,4.] (target 1.3)
at q95=6.5

Now try for the q95= 3.7 case, as in step 2 today.
Jul 27 2005 04:24:06:233PM1050727031John Rice1.05 MA, 5.6 T
nebar target of 1.4
ELM-free H-modes
Jul 27 2005 04:48:44:687PM1050727033John Rice1.05 MA, 5.6 T
nebar target of 1.7
brief H-mode
Jul 27 2005 05:01:37:187PM1050727034John Rice1.05 MA, 5.6 T
nebar target of 1.7
ELM-free H-modes
Jul 27 2005 05:12:24:827PM1050727034John DegrassieNeeded more rf power to raise Te at the highest
density excursions. Probably could have achieved
the necessary n and Te given time (4.7, 2.15)

But there will be useful rotation comparison data
for this shot, which did have matches to nu at
lower Beta.

Physics Operator Comments
Jul 27 2005 09:20:41:083AMRon ParkerA hot day today -- forecast is for 96 F with high humidity.

Today we'll carry out MP 425, comparing toroidal rotation in dimensionally similar discharges in C-Mod and DIII-D.

At suggestion of S. Wolfe, we'll start with loading shot 1050726008 with field set at 3.75 T.
Jul 27 2005 09:14:21:130AM1050727001Ron ParkerShot 1 ran well, but field a little too high, 3.85 T and no sustained H-mode.

Same shot coming up with field reduced to 3.75 T and RF tuned up.
Jul 27 2005 09:27:37:397AM1050727002Ron ParkerShot 2 ran well, with field ~ 3.75 T. H-mode still intermittent.

We'll raise target density from 5 to 6e19 (n_eL(4)) for next shot.
Jul 27 2005 09:34:59:960AM1050727003Ron ParkerShot 3 was a dud. Raise the fill pressure by 2 ms (20 vs 18)
Jul 27 2005 09:51:24:880AM1050727004Ron ParkerShot 4 ran, still intermittent H-modes.

Fill pressure still rather low, increase to 22 ms for next shot.

Cell opening, short delay.
Jul 27 2005 09:56:46:070AM1050727005Ron ParkerShot 5 ran OK, but no improvement in H-modes.

Next: Raise target density from 6 to 7e19.
Jul 27 2005 10:22:08:130AM1050727006Ron ParkerShot 6 ran well with steady H-mode.

Next Ar (1 psi) & Ne (2 psi) will be injected.
Jul 27 2005 10:23:04:083AM1050727007Ron ParkerH-mode not as steady, maybe a bit too much Ar and Ne. Reduce by 2 ms for
next shot.
Jul 27 2005 10:45:10:070AM1050727008Ron Parkerbeginning to look better.

Still too much Ar+Ne, reduce by 2 more ms.
Jul 27 2005 10:52:57:427AM1050727009Ron ParkerShot 9 looked OK.

Ar+Ne puff will ne reduced to 20 ms and target density will be reduced by 10%,
from 7 to 6.3e19 (nL_04)
Jul 27 2005 11:09:25:943AM1050727010Ron ParkerShot 10 was good. It satisfied the first shot requirement for the MP.

Next: Raise current to 0.75 MA
Jul 27 2005 11:21:44:647AM1050727011Ron ParkerBack to intermittent H-mode. Need to raise target density.

Raise target n to 7.3e19 (nL_04) for next shot.
Jul 27 2005 11:34:43:740AM1050727012Ron ParkerShot 12 was close to requested, but steady H-mode a bit short.

Next: reduce target density from 7.3 to 7e19 m-2.


Jul 27 2005 11:45:49:833AM1050727013Ron ParkerShot 13 ran OK, but non-steady H-mode.

Next: Raise target to 7.6e19 m-2.
Jul 27 2005 11:57:09:833AM1050727014Ron ParkerShot 14 ran well, good steady EDA.

Next: More RF power to raise Te.

RF power increase from 1.5 to 2 MW
Jul 27 2005 12:19:54:467PM1050727015Ron ParkerShot 15 ran OK, but with some RF trips.

try again, slightly lower RF power.
Jul 27 2005 12:25:46:087PM1050727016Ron ParkerStill non-steady EDA.

Next: try lowering target density to 7.4 e19 m-2.
Jul 27 2005 12:41:00:030PM1050727017Ron ParkerShot 17 ran well and is about as close as we'll come to the shot for Case 2.

Next: Reduce current to 430 kA, and target density to 5.0 e19 m-2.
Jul 27 2005 12:49:27:513PM1050727018Ron Parkershot 18 ran OK, trip in RF.

Next: reduce current to 400 kA.
Jul 27 2005 01:18:47:937PM1050727019Ron ParkerShot 19 looked good, but density was a bit too high. We'll lower target n for next shot.
Jul 27 2005 01:23:01:733PM1050727020Ron ParkerShot 20 ran OK, but density was not lower than on previous shot.

Shot 19 was closer to the shot desired for Case 3 on the run plan.
Jul 27 2005 01:55:45:000PM1050727020Ron ParkerOK, we're moving on to Case 4, 5.63 T, 860 kA, target nl_04= 9e19 cm-2. He3 minority.

But there'll be a slight delay for cell and lab access.
Jul 27 2005 01:58:16:530PM1050727021Ron ParkerGood shot, but no H-Mode. He3 fraction too high or too low?

Next: Try higher power on J port. Argon puff will be increased to 30 ms.


Jul 27 2005 02:11:49:483PM1050727022Ron ParkerGood shot, but no H-mode.

Next: Switch from J-port (50 MHz) to E-port (80 MHZ) and drop current to 800 kA.

Add 10 more ms to Ar+Ne.
Jul 27 2005 02:20:56:483PM1050727023Ron ParkerShot 23 ran, but with only a late H-mode.

Next: Run shot again with J port on as well.
Jul 27 2005 02:30:32:500PM1050727024Ron ParkerA dud! No particular reason.
Jul 27 2005 02:54:14:153PM1050727025Ron ParkerShot ran OK, but intermittent H-Mode.

Next: same shot, target density = 1.1e20 m-2.
Jul 27 2005 03:28:38:483PM1050727026Ron ParkerOops, disruption. OH2 Lower Power supply crowbarred before the disruption.
No apparent cause.

Next: OH2 Lower test.
Jul 27 2005 03:39:30:670PM1050727027Ron ParkerShot 27 was an OH2 lower test. Test was normal and we'll set up to rerun shot 26.
Jul 27 2005 03:54:46:187PM1050727028Ron ParkerShot 28 ran well, no problems with OH2.

Good sustained H-Mode.

Next: Lower current to 600 kA and density by 10%.
Jul 27 2005 04:02:38:200PM1050727029Ron ParkerShot ran, but Marfed due to high density.

Next: Lower target density to 0.9e20 m-2.
Jul 27 2005 04:15:57:653PM1050727030Ron ParkerShot 30 ran better than 29, no apparent Marfe. Sustained H-Mode.

Next: increase current to 1.05 MA.


Jul 27 2005 04:24:02:483PM1050727031Ron ParkerShot ran with lots of ELM free H-Modes.

Next: Repeat with 10% higher density.
Jul 27 2005 04:38:34:297PM1050727032Ron ParkerShot 32 ran OK but no H-Mode with 1 MW out of E-port.

Next: increase E-port power to 1.5 MW.
Jul 27 2005 05:00:18:000PM1050727034Ron ParkerShot 34 ran well, but without sustained H-Mode.

Engineering Operator Comments
ShotTimeTypeStatusComment
109:01:04:897AMPlasmaOk
209:15:20:973AMPlasmaOk
309:27:55:240AMPlasmaOk
409:41:06:880AMPlasmaOk
509:53:54:460AMPlasmaOk
610:06:42:443AMPlasmaOk
710:19:14:410AMPlasmaOk
810:31:45:990AMPlasmaOk
910:44:23:303AMPlasmaOk
1011:01:14:897AMPlasmaOk
1111:13:58:740AMPlasmaOk
1211:26:56:677AMPlasmaOk
1311:39:39:833AMPlasmaOk
1411:52:33:943AMPlasmaOk
1512:05:09:740PMPlasmaOk
1612:18:42:270PMPlasmaOk
1712:31:22:860PMPlasmaOk
1812:43:55:857PMPlasmaOk
1912:56:36:780PMPlasmaOk
2001:18:16:153PMPlasmaOk
2101:50:17:047PMPlasmaOk
2202:03:22:717PMPlasmaOk
2302:15:50:983PMPlasmaOk
2402:28:12:607PMPlasmaOk
2502:40:50:827PMPlasmaOk
2602:54:56:653PMPlasmaBadOH2L Power Supply Crowbars at 0.5 secs
2703:28:48:200PMTestOkOH2L PLC Test
2803:41:03:450PMPlasmaOk
2903:54:23:217PMPlasmaOk
3004:07:15:327PMPlasmaOk
3104:20:12:843PMPlasmaOk
3204:32:52:327PMPlasmaOk
3304:45:16:670PMPlasmaOk
3404:58:00:653PMPlasmaOk