Alcator C-Mod Run 1031209 Information

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Miniproposals
Miniproposal:376
Date Filed:11/25/2003
Title:Study of the Efficiency of ICRF Minority Heating and Investigation of the Cause of Low H-mode Plasma
First Author:Yijun Lin
Session Leader:Yijun Lin (shots 1-34)

Operators
Session leader(s):Yijun Lin
Physics operator(s):Dmitri Mossessian
Engineering operator(s): Unknown

Engineering Operator Run Comment
MP#376--- Study of the Efficiency of ICRF Minority Heating and Investiga

Session Leader Plans

Physics Operators Plans

Session Leader Summaries
Entered: Jul 7 2004 03:49:35:227PM
Author: Yijun Lin

Run summary:
MP376, part 1. RF efficiency and plasma performance study

Scans on outer gap, upper triangularity, and lower triangularity
was done to figure out whether these parameters do matter.

*Summary on outer gap scan (shots 2, 3, 6, 8). Insensitive

*Summary on delta_u scan: Plasma performance is rather insensitive to
delta_u from 0.3 to 0.5 (shot 10, 12, 13).
A larger delta_u produces plasmas more EDA like.
A very small delta_u = 0.2 get a slightly
lower performance plasma (shot 18).

*Summary on delta_l scan (shot 19, 20, 21, 23, 24, 25, 26, 28, 11).
Generally, larger delta_l produces H-modes more EDA-like.
H-modes with larger delta_l also tend to have lower stored energy.
The max stored energy obtained was in shot 23 at delta_l = 0.45,
which is about the smallest delta_l we can go safely.

*Summary on power scan: shot 23, 30, 32, 33
The result is inconclusive. It seems the max stored energy is
sensitive to rf trips; unfortunately, we were not able to run
clean rf at 5 MW level (30, 32). More scan will be performed
tomorrow.

Generally, the plasma performance is better than the norm in year 2002
and 2003 campaign. 4 MW, W~170 kJ are routinely obtained in many different
shapes.


Physics Operator Summaries

Session Leader Comments
Dec 9 2003 05:06:02:987PMYijun LinRun summary:


Run summary:
MP376, part 1. RF efficiency and plasma performance study

Scans on outer gap, upper triangularity, and lower triangularity
was done to figure out whether these parameters do matter.

*Summary on outer gap scan (shots 2, 3, 6, 8). Insensitive

*Summary on delta_u scan: Plasma performance is rather insensitive to
delta_u from 0.3 to 0.5 (shot 10, 12, 13).
A larger delta_u produces plasmas more EDA like.
A very small delta_u = 0.2 get a slightly
lower performance plasma (shot 18).

*Summary on delta_l scan (shot 19, 20, 21, 23, 24, 25, 26, 28, 11).
Generally, larger delta_l produces H-modes more EDA-like.
H-modes with larger delta_l also tend to have lower stored energy.
The max stored energy obtained was in shot 23 at delta_l = 0.45,
which is about the smallest delta_l we can go safely.

*Summary on power scan: shot 23, 30, 32, 33
The result is inconclusive. It seems the max stored energy is
sensitive to rf trips; unfortunately, we were not able to run
clean rf at 5 MW level (30, 32). More scan will be performed
tomorrow.

Generally, the plasma performance is better than the norm in year 2002
and 2003 campaign. 4 MW, W~170 kJ are routinely obtained in many different
shapes.
Dec 9 2003 10:27:21:457AM1031209001Yijun LinShot 01
Load 1031205021
Fiducial shot. 1 MA. nl04 = 0.8e20 m^-2
Kappa = 1.7, right gap 0.8, delta_l = 0.56, delta_u= 0.29
RF step up 2, 3, 4 MW.
Good shot.
Wmhd to 186 kJ at 3.5 MW rf.

D-port did not fire. A problem in the control system.
No modulator output.

Run without D port. Start outgap scan at 3.6 MW level.

Dec 9 2003 09:49:40:313AM1031209002Yijun LinShot 02:
Same plasma as shot 01. Outer gap = 1 cm at H-modes.
delta_l = 0.56, delta_u= 0.29
RF at 3.6 MW (E + J)
Wmax = 187 kJ.

Next: larger outer gap.

Dec 9 2003 10:38:34:733AM1031209003Yijun LinShot 03:
Same plasma as shot 01. Outer gap = 1.5 cm at H-modes.
delta_l = 0.56, delta_u= 0.29
RF at 3.6 MW.
Wmax = 174 kJ in the First H-mode.

Next: more outer gap
Dec 9 2003 10:18:52:520AM1031209004Yijun Lin
Disrupted @ 0.83 sec. A problem in density feedback.
Dec 9 2003 10:37:56:627AM1031209005Yijun Linshot 05:
No power shot. OH2 problema.
Dec 9 2003 11:03:32:503AM1031209007Yijun Linshot 07:
Plasma. Run-away. Ultra-low density (1.e19).
Dec 9 2003 01:44:00:593PM1031209008Yijun Linshot 08:
Programed E port [0.6, 1.2] sec.
J port [0.6, 1.3] sec. So dW/dt may be done at 1.2 sec.
Outer gap = 1 cm in H-modes.(it is evolving. Average about 0.8 cm)
delta_l = 0.56, delta_u= 0.29
RF at 3.6 MW.
Wmax = 183kJ in the 1st H-mode, 177 kJ 3rd H-modes.


Summary on outer gap scan:
At large outer gap, Wmax is similar, but later H-modes become much
worse than the first one. (shot 2, 3, 6, 8)

Next: start delta_u scan. Repeat shot 2 with all antennas.
Dec 9 2003 11:41:51:053AM1031209009Yijun LinShot 09:
Repeat shot 02.
With D, E and J antennas (demand 0.9 MW each transmitter)
E port has two notches at 0.8 sec and 1.1 sec.
Outer gap = 1 cm, delta_l = 0.56
delta_u = 0.3
Only 3 MW. D port has phase balance faults. (by-passed for the next shot).
Wmax ~ 160 kJ.

Density to 0.9 e20 to get H-modes more EDA like.

Dec 9 2003 11:49:11:097AM1031209010Yijun LinShot 10:
Ip: 1 MA, nl04: 0.9e20 m^-2
With D, E and J antennas (demand 0.9 MW each transmitter)
E port has two notches at 0.8 sec and 1.1 sec.
Outer gap = 1 cm, delta_l = 0.56

delta_u = 0.3
Prf = 4 MW.
Wmax ~ 173 kJ (1st H-mode)
Wmax ~ 177 kJ (2nd H-mode)

Next: run delta_u ~ 0.4
Dec 9 2003 12:05:59:777PM1031209011Yijun LinShot 11:
Ip: 1 MA, nl04: 0.9e20 m^-2
With D, E and J antennas (demand 0.9 MW each transmitter)
E port has two notches at 0.8 sec and 1.1 sec.

Request: Outer gap = 1 cm, delta_l = 0.56
delta_u = 0.4

PO mistake. Got delta_l = 0.7, delta_u = 0.29

Prf = 4 MW.

Wmax ~ 152 kJ H factor ~ 1.0

Next: run delta_u ~ 0.4, delta_l = 0.56


Dec 9 2003 12:36:35:423PM1031209013Yijun LinShot 13:
Ip: 1 MA, nl04: 0.9e20 m^-2
With D, E and J antennas (demand 0.9 MW each transmitter)
E port has two notches at 0.8 sec and 1.1 sec.
Outer gap = 1 cm, delta_l = 0.56

delta_u = 0.5
Prf = 4 MW.
Wmax ~ 172 kJ (1st H-mode)
Wmax ~ 190 kJ (2nd H-mode) (Delta_u was going down in the 2nd H-mode)

Next: delta_u = 0.65
Dec 9 2003 01:02:23:300PM1031209015Yijun LinShot 15:
Ip: 1 MA, nl04: 0.9e20 m^-2
With D, E and J antennas (demand 0.9 MW from each transmitter)
E port has two notches at 0.8 sec and 1.1 sec.
Outer gap = 1 cm, delta_l = 0.56
delta_u = 0.55
Plasma was innerwall limited.

Prf = 2 MW. No J port power. Unknown reason. Fine in dummy load tests.
Wmax ~ 114 kJ (Long innerwall limited EDA H-mode?), H-factor ~ 1.5
Dec 9 2003 01:09:39:723PM1031209016Yijun LinShot 16:
Ip: 1 MA, nl04: 0.9e20 m^-2
With D, E and J antennas (demand 0.9 MW from each transmitter)
E port has two notches at 0.8 sec and 1.1 sec.
Outer gap = 1 cm, delta_l = 0.56
delta_u = 0.65
Prf = 4 MW.
Wmax ~ 156 kJ
Disrupted at 0.82 sec. Still goes limited. H factor ~ 1.7

Next: try delta_u ~ 0.2.

Dec 9 2003 01:25:01:213PM1031209017Yijun LinShot 17:
Ip: 1 MA, nl04: 0.9e20 m^-2
With D, E and J antennas (demand 0.9 MW from each transmitter)
E port has two notches at 0.8 sec and 1.1 sec.
Outer gap = 1 cm, delta_l = 0.56
delta_u = 0.25
Prf ~ 1 MW. Density control problems. No H-mode
Dec 9 2003 01:56:34:007PM1031209018Yijun LinShot 18:
Ip: 1 MA, nl04: 0.9e20 m^-2
With D, E and J antennas (demand 0.9 MW from each transmitter)
E port has two notches at 0.8 sec and 1.1 sec.
Outer gap = 1 cm, delta_l = 0.56
delta_u = 0.22
Prf = 4 MW.
Wmax ~ 154 kJ, H factor < 1.5

Summary on delta_u scan: Plasma performance is rather insensitive to
delta_u from 0.3 to 0.5 (shot 10, 12, 13).
A larger delta_u produces plasmas more EDA like.
A very small delta_u = 0.2 get a lower performance plasma (shot 18).
(compared with shot 19. it seems the lower performance in
shot 18 might not be due to the delta_u change).

Next: Start delta_l scan. Repeat shot 10 to be sure we are getting the
same plasma performance.
Dec 9 2003 01:59:23:837PM1031209019Yijun Linshot 19: repeat shot 10
Ip: 1 MA, nl04: 0.96e20 m^-2
With D, E and J antennas (demand 0.9 MW from each transmitter)
E port has two notches at 0.8 sec and 1.1 sec.
Outer gap = 1 cm, delta_l = 0.56
delta_u = 0.3
Prf = 4 MW.
Wmax ~ 160 kJ H factor 1.5. (density is a little bit higher than shot 10).

Next: smaller delta_l.
Dec 9 2003 02:12:54:467PM1031209020Yijun Linshot 20:
Ip: 1 MA, nl04: 0.9e20 m^-2
With D, E and J antennas (demand 0.9 MW from each transmitter)
E port has two notches at 0.8 sec and 1.1 sec.
Outer gap = 1 cm, delta_u = 0.3
delta_l = 0.5
Prf = 4 MW.
Wmax ~ 177kJ, H factor 1.7. (Better than shot 19)

Next: lower delta_l more.
Dec 9 2003 02:33:18:973PM1031209022Yijun Linfizzle
Dec 9 2003 02:48:42:997PM1031209023Yijun LinIp: 1 MA, nl04: 0.9e20 m^-2
With D, E and J antennas (demand 0.9 MW from each transmitter)
E port has two short notches at 0.88 sec and 1.2 sec.
Outer gap = 1 cm, delta_u = 0.3
delta_l = 0.45
Prf = 4 MW.
Wmax ~ 186 kJ, H factor max at 2, then comes down with radiation.
The Hmodes are less EDA like.

Next: repeat shot 20. With shortened E port notch to see how high
we can get on stored energy.


Dec 9 2003 02:59:44:233PM1031209024Yijun Linshot 24:
Ip: 1 MA, nl04: 0.9e20 m^-2
With D, E and J antennas (demand 0.9 MW from each transmitter)
E port has two short notches at 0.88 sec and 1.2 sec.
Outer gap = 1 cm, delta_u = 0.3
delta_l = 0.50
Prf = 4 MW.
Wmax ~ 175 kJ, H factor 1.7
W starts rolling over while J-port faulted.

Next: the same plasma. Slightly lower J power to let it stay on.
Dec 9 2003 03:30:12:353PM1031209026Yijun Linshot 26:
Ip: 1 MA, nl04: 0.9e20 m^-2
With D, E and J antennas (demand 1.1 MW from D and E, 1.4 MW from J)
E port has two short notches at 0.88 sec and 1.2 sec.
Outer gap = 1 cm, delta_u = 0.3
delta_l = 0.50
Prf = 4 MW.
Wmax ~ 174 kJ, H factor 1.7
Long EDA, but Wmhd droops.

Next: delta_l = 0.6. Set all antennas equal power again.
Dec 9 2003 03:50:30:270PM1031209028Yijun Linshot 28:
Ip: 1 MA, nl04: 0.9e20 m^-2
With D, E and J antennas (demand 0.9 MW from each transmitter)
E port has two short notches at 0.88 sec and 1.2 sec.
Outer gap = 1 cm, delta_u = 0.3
delta_l = 0.6
Prf = 4 MW.
Wmax ~ 146 kJ

Summary on delta_l scan (shot 19, 20, 21, 23, 24, 25, 26, 28, 11).
Generally, larger delta_l produces H-modes more EDA-like.
H-modes with larger delta_l also tend to have lower stored energy.
The max stored energy obtained was in shot 23 at delta_l = 0.45,
which is about the smallest delta_l we can go safely.

Next power scan at the best shape (shot 23).
Dec 9 2003 03:58:23:367PM1031209029Yijun Linfizzle
Dec 9 2003 04:18:46:530PM1031209030Yijun LinIp: 1 MA, nl04: 0.9e20 m^-2
With D, E and J antennas (demand 1.15 MW from D and E, 2.2 MW from J)
E port has two short notches at 0.88 sec and 1.2 sec.
Outer gap = 1 cm, delta_u = 0.3
delta_l = 0.46
Prf = 5 MW.
Wmax ~ 150 kJ. RF faulted at 0.67 sec. Wmhd was still rising before rf faults.

Next: same plasma. Lower J power. Raise D and E power.
Dec 9 2003 04:29:07:753PM1031209030Yijun Linshot 31:
No power shot. Hung during INIT.
Dec 9 2003 04:53:46:683PM1031209032Yijun Linshot 32:
Ip: 1 MA, nl04: 0.9e20 m^-2
With D, E and J antennas (demand 1.2 MW from D and E, 2. MW from J)
E port has two short notches at 0.88 sec and 1.2 sec.
Outer gap = 1 cm, delta_u = 0.3
delta_l = 0.46
Prf = 4.8 MW.
Wmax ~ 173 kJ.

Next: try 3 MW Prf.
Dec 9 2003 04:54:04:823PM1031209033Yijun Linshot 33:
Ip: 1 MA, nl04: 0.9e20 m^-2
With D, E and J antennas (demand 0.7 MW from each transmitter)
E port has two short notches at 0.88 sec and 1.2 sec.
Outer gap = 1 cm, delta_u = 0.3
delta_l = 0.46
Prf = 3.1 MW.
Wmax ~ 140 kJ.

Next Try 5 MW again.
Dec 9 2003 05:05:08:313PM1031209034Yijun Linfizzle

Physics Operator Comments
Dec 9 2003 09:00:35:223AMDmitri MossessianWolfe filling in for Dmitri for first shot.
Per SL request loaded 1031205021 which has different gaps from
Friday's fiducial.

Dmitri is back.

Loaded 1031205021 (Steve reloaded it).
Plan:

MP#376 --- Study of the Efficiency of ICRF Minority Heating and
Investigation of the Cause of Low H-mode Plasma Performance

Scan plasma shape
1. outer gap scan (0.5,1.,1.5,2.0 cm) with fixed triangularity
2. scan upper triangularity (0.05,.15,.25,.35,.45,.6) with fixed
lower triangularity and gap
3. scan lower triangularity with fixed upper triangularity and gap
With identified best shape perform power scan - 2.5, 4, 5.5 MW

Scan plasma current for fixed power (Prf ~ 4 MW)
1. for best performing shape scan plasma current (0.6,0.8,1.0,1.2 MA)
2. for poorest performing shape scan plasma current (0.6,0.8,1.0,1.2 MA)
Antenna comparison in H-mode
1. D, E, and J-port at 1 MW each, J-port at 3 MW
2. D and E at 3.0 MW, J-port at 3.0 MW
He plasma comparison
1. Fiducial discharge in He

for all discharges except the fiducial a programmed RF transition will occur at 1.2 sec

Dec 9 2003 09:04:52:880AM1031209001Dmitri MossessianPlasma. Startup looks OK.
PLC fault - lost communication with TORVAC.

Next shot - no PCS changes
Dec 9 2003 09:50:31:050AM1031209002Dmitri MossessianPlasma.

Next shot: Right gap 0.5 cm larger - RCUR 0.666 -> 0.6635
Dec 9 2003 10:05:06:730AM1031209003Dmitri MossessianPlasma.

Next shot: Right gap 0.5 cm larger - RCUR 0.635 -> 0.661
Dec 9 2003 10:18:42:460AM1031209004Dmitri MossessianPlasma. Disrupted at 0.82 sec - problems with density feedback because of a fringe jump
at the beginning of the shot, the gas was shut off fro the whole shot.

Next shot: repeat
Dec 9 2003 10:28:20:113AM1031209005Dmitri MossessianNo power shot. OH2 problems
Dec 9 2003 11:15:36:953AM1031209007Dmitri MossessianPlasma. No density feedback after 0.2 sec - we got 8e18 m^-3 at 1 sec.

Next shot: TCI may be fixed. We'll try again.
Dec 9 2003 11:23:36:763AM1031209008Dmitri MossessianPlasma. TCI is Ok

Next shot: go to right gap from shot 2 - RCUR to 0.666
Dec 9 2003 11:38:56:070AM1031209009Dmitri MossessianPlasma.

Next shot: go to target nl 0.9e20
Dec 9 2003 11:56:41:907AM1031209010Dmitri MossessianPlasma. Traces of QC mode.

Next shot: raise upper triangularity RXL 0 -> -.02
Dec 9 2003 12:04:32:683PM1031209011Dmitri MossessianPlasma. Changed lower delta instead of upper.

Next shot: RXL back to 0. RXU decreased by 2 cm
Dec 9 2003 12:18:32:507PM1031209012Dmitri MossessianPlasma. Good shot - EDA with small ELMs at 180 kJ max W

Next shot: Raise upper delta - RXU decreased by 2 cm
Dec 9 2003 12:32:16:750PM1031209013Dmitri MossessianPlasma.

Next shot: RXU decreased by 1 cm
Dec 9 2003 12:49:51:010PM1031209014Dmitri MossessianPlasma. Goes limited because upper x-point is not at the right place

Next shot: ZXU decreased by 2 cm
Dec 9 2003 12:57:34:610PM1031209015Dmitri MossessianPlasma. Goes limited again, but seems to be changed in the right direction.
Wolfe taking over for a shot or two.

Next shot: Move ZXU from .03 to .01
Dec 9 2003 01:09:07:850PM1031209016Dmitri MossessianShot 16: Move ZXU from .03 to .01
plasma disrupted at 0.81 sec. xpoint is right on the wall.

next shot: Give up on the high triang. point and try for deltau=0.2

Dec 9 2003 01:27:21:760PM1031209017Dmitri MossessianShot 17: Import seg2 from shot 10 and add .01 to every point from .47sec on
Mossessian is back.

Plasma. TCI is bad - we lost feedback and got too high nl target - lost J-port.

Next shot: Move RXU out 1 cm - trying to get upper delta of 0.2




Dec 9 2003 01:42:57:360PM1031209018Dmitri MossessianPlasma. TCi is OK. Delta upper =0.2

Next shot: load segment 2 from shot 10
Dec 9 2003 01:55:54:240PM1031209019Dmitri MossessianPlasma.

Next shot: smaller lower delta - move RXL out 1 cm
Dec 9 2003 02:07:55:667PM1031209020Dmitri MossessianPlasma. Lower triangularity 0.5

Next shot: smaller lower delta - move RXL out 1 cm
Dec 9 2003 02:20:20:920PM1031209021Dmitri MossessianPlasma. Lower triangularity 0.45

Next shot: repeat
Dec 9 2003 02:33:13:707PM1031209022Dmitri MossessianFizzle. Fields and current rise are exactly the same as on shot 21

Next shot: no change
Dec 9 2003 02:47:09:743PM1031209023Dmitri MossessianPlasma. W peaks at 186. Two periods with small ELMs

Next shot: load segment 2 from shot 20
Dec 9 2003 03:01:27:017PM1031209024Dmitri MossessianPlasma. Good EDA with ELMs

Next shot: repeat
Dec 9 2003 03:10:09:097PM1031209025Dmitri MossessianPlasma. RF trips more, otherwise similar to 24

Next shot: repeat
Dec 9 2003 03:34:56:497PM1031209027Dmitri MossessianFizzle. As unexplicable as the previous one.

Next shot: no changes
Dec 9 2003 03:49:15:050PM1031209028Dmitri MossessianPlasma

Next shot: load segment 2 from shot 23
Dec 9 2003 04:01:46:180PM1031209029Dmitri MossessianFizzle. Bz is slightly lower than before.

Next shot: IC_EF4U -1335 -> -1325
Dec 9 2003 04:14:57:763PM1031209030Dmitri MossessianPlasma. RF trips a lot

Next shot: Bz is back where it was. Repeat.
Dec 9 2003 04:29:09:893PM1031209031Dmitri MossessianNo power shot - computer problems at INIT
Dec 9 2003 04:40:13:413PM1031209032Dmitri MossessianPlasma, H-modes with small ELMs

Next shot - repeat.
Dec 9 2003 04:52:58:903PM1031209033Dmitri MossessianPlasma,

Next shot - repeat.
Dec 9 2003 05:01:31:670PM1031209034Dmitri MossessianFizzle.

Engineering Operator Comments
ShotTimeTypeStatusComment
108:56:28:040AMPlasmaOk
209:42:57:210AMPlasmaOk
309:56:53:373AMPlasmaOk
410:09:22:307AMPlasmaOk
510:21:57:177AMPlasmaBadOH2 State Flt
610:46:09:917AMPlasmaOk
710:59:45:240AMPlasmaOk
811:17:06:343AMPlasmaOk
911:29:58:840AMPlasmaOk
1011:43:57:723AMPlasmaOk
1111:58:06:483AMPlasmaOk
1212:10:55:510PMPlasmaOk
1312:24:44:130PMPlasmaOk
1412:37:17:803PMPlasmaOk
1512:51:05:513PMPlasmaOk
1601:04:05:347PMPlasmaOk
1701:19:11:947PMPlasmaOk
1801:35:36:750PMPlasmaOk
1901:48:17:300PMPlasmaOk
2002:00:55:180PMPlasmaOk
2102:13:51:840PMPlasmaOk
2202:26:16:770PMPlasmaOk
2302:39:20:350PMPlasmaOk
2402:51:55:030PMPlasmaOk
2503:04:45:940PMPlasmaOk
2603:17:16:320PMPlasmaOk
2703:30:46:573PMPlasmaOk
2803:43:50:237PMPlasmaOk
2903:56:20:723PMPlasmaOk
3004:09:06:900PMPlasmaOk
3204:32:33:113PMPlasmaOk
3304:45:15:633PMPlasmaOk
3404:57:47:687PMPlasmaOk