Alcator C-Mod Run 990304 Information

Back to runs

Miniproposals
Miniproposal:216
Date Filed: 1/12/1999
Title:Edge pedestals
First Author:Robert Granetz
Session Leader:Robert Granetz (shots 1-13)
Miniproposal:226
Date Filed: 1/15/1999
Title:Multi-Diagnostic Characterization of the Edge
First Author:Spencer Pitcher
Session Leader:Spencer Pitcher (shots 14-25)

Operators
Session leader(s):Robert Granetz,Spencer Pitcher
Physics operator(s):Ron Parker
Engineering operator(s): Unknown

Engineering Operator Run Comment
MP216,MP226

Session Leader Plans

Physics Operators Plans

Session Leader Summaries
Entered: Jul 7 2004 03:49:19:947PM
Author: To Be Determined
Run summary for run 990304A

MP 216 -- Edge pedestal scaling with dIp/dt

SL: R. Granetz
PO: R. Parker

The primary goal for this half-day run is to determine the dependence of
pedestal width on dIp/dt. A secondary goal is to measure the Te pedestal
width at two different currents on the same shot.

Summary: The secondary goal was accomplished on shot 13, with the expected
result that the Te H-mode pedestal width is indeed independent of
plasma current. The primary goal was only partially accomplished,
with some observations of a dIp/dt dependence of the xray width at
0.8 and 1.0 MA (990304003, 990304007). The measurements are not
as clear as hoped, primarily because the maximum available RF power
(1.0 MW) was not enough to give long-duration H-modes.

------------------------------------------------------------------------------

Shot 01 -- Fizzle.

Shot 02 -- Plasma. 0.8 MA steady-state. Long EDA H-mode. Good xray pedestal
data. Top width is 2.2-2.6 mm, outboard width is 3.0-3.5 mm.

Next shot: load the up/down 0.8 MA ramping shot.

Shot 03 -- Plasma. Good 0.8 MA up/down ramping shot. Peak-to-peak variation
of Ip is about 70 kA, which is somewhat less than the 100 kA
variation that we asked for. Xray pedestal widths definitely show
a difference between + and - dIp/dt. Difference is consistent with
dependence seen a year ago.

Next shot: load the 1.0 MA steady-state shot.

Shot 04 -- Plasma. Good 1.0 MA steady-state shot. EDA H-mode from t=0.75 to
1.1 s. Widths were reasonably constant, but not as steady as at
0.8 MA.

Next shot: load the 1.0 MA oscillating shot.

Shot 05 -- Fizzle.

Shot 06 -- Fizzle.

Shot 07 -- Plasma. Good 1.0 MA oscillating shot. EDA H-mode from t=0.62 to
1.2, with a short L-mode at 1.02 s. Outboard pedestal width varies
with dIp/dt as expected. Top width is not as clear.

Next shot: try 1.2 MA steady-state

Shot 08 -- Plasma. Good 1.2 MA steady-state shot. Prf=1.0 MW. Two long EDA
H-modes (close to being ELMfree). Edge xray emissivity amplitude
increases with plasma current. The outboard width is noticeably
narrower (1.6 mm) than at lower currents, as expected.

Next shot: try 1.2 MA oscillating shot.

Shot 09 -- Plasma. Good 1.2 MA oscillating shot. Prf=1.0 MW. Two long EDA
H-modes. The xray pedestal widths didn't show much dependence on
dIp/dt at this current.

Next shot: retry the 0.8 MA oscillating shot, except put in some
neon to enhance the edge xray signals.

Shot 10 -- Plasma. Good 0.8 MA oscillating shot, but some of the magnetics
data acquisition was corrupted, resulting in problems for EFIT.
Also, there was only one short H-mode (1.0-1.2 s).

Next shot: repeat with no changes.

Shot 11 -- Plasma. Good 0.8 MA oscillating shot, but again there was only one
short H-mode.

Next shot: do a dynamic Ip ramp from 0.8 to 1.1 MA, with a B-field
bump at the 0.8 MA level and another B-field bump at the 1.1 MA
level. Also: no neon puff.

Shot 12 -- Plasma. Good dynamic Ip ramp, but there were no H-modes. RF turned
off at 0.9 s, and Prf=0.9-1.0 MW.

Next shot: repeat, with 10% more RF power.

Shot 13 -- Plasma. Good dynamic Ip ramp, with two H-modes which are at the
times of the Bp bumps. The outboard pedestal width at the higher
current is nearly a factor of 2 less than at the lower current.
HOWEVER, the GPC and TS temperature pedestals show NO difference
at the two currents (0.8 and 1.1 MA) !!! This confirms last year's
findings, but on a single shot.

End of my half of the run day.

Entered: Jul 7 2004 03:49:20:133PM
Author: To Be Determined
Run Summary for 990304b

MP 226 Multi-Diagnostic characterization of the edge
Half-Day Run

Session Leader: S Pitcher
Phys Op : R Parker

Purpose:

Obtain a complete set of edge profiles with all available
edge diagnostics....primary ones being, asp, fsp, ECE, Thomson
and Kaiser.

Operation:

We set up the following plasma:

Ohmic 0.4 s to 0.7 s
RF 1 MW 0.7 s to 1.2 s

For edge Thomson:
vertical position scan 2 cm upwards 0.4 s to 0.7 s
vertical position scan 2 cm downwards 0.9 s to 1.2 s

for ECE:
Btor wobbles at approx 0.6 s and 0.9 s

target nl04 = 1.0 (18,19), 0.7 (21,22), 1.3 (23,25, Ohmic only)

Summary:

We had a late start (first good plasma 3:07 PM).
Machine ran well once we got going. Nice long
EDA's at 1 MW at target nl04 = 0.7 and 1.0 (n04 = 1.3
was essentially Ohmic). The primary edge
diagnostics (including the new Kaiser spectrometer-
helium beam) all worked. We have a range of conditions,
ie different densities, Ohmic and EDA. We should
have comparisons done before operation resumes
two weeks hence.



Physics Operator Summaries
Entered: Jul 7 2004 04:37:00:740PM
Author: To Be Determined
RUN SUMMARY: 990304

PHYS OP: R. PARKER
PHYS RUN LEADERS: R. GRANETZ, S. PITCHER

The run began by setting up shot 990303013, which produced a fizzle. This was diagnosed as due to the
pumped-out walls which had been overnight conditioned by He ECDC, contrary to the D2 ECDC which had
been requested. By increasing the fill gas to 8-9 10**-5 T, a good plasma was produced on the second
shot.

During the day, some tweaking of BR(t=0) was required as well as of the fill pressure. At the end of
the day, BR(0) was set at only 0.5 mT.

Of the 25 shots, 6 were fizzles, one failed due to a slippage in alternator speed and another due to
failure to initiate EF4 after the alternator problem. The 17 successful shots conformed to the
physics run leader's requests and mostly produced useful data.

On the whole, the run was not remarkable from the operator's point of view, although it could be
mentioned that there
were no disruptions.

Session Leader Comments
Mar 4 1999 08:06:15:107AMRobert GranetzRun Plan for 990304:

MP 216 -- Edge pedestal scaling with dIp/dt
MP 226 -- Multi-diagnostic characterization of edge

SL: R. Granetz/S. Pitcher
PO: R. Parker

Load PCS from shot 990303013 (0.8 MA, 5.4 T, 1.0e20 m-2), but with Btor ramps
at 0.5 and 1.1 s. Turn RF on from t=0.45 (or even earlier) until t=1.20 s.

Today's operation consists of two half-day runs. The goal of the first
part of the day is to measure the dependence of the edge xray pedestal width on
dIp/dt. We will operate at Ip=0.8, 1.0, and 1.2 MA, some with steady-state
plasma current, and some with +/- 50 kA up/down ramps superimposed on Ip.
We will also run at least one dynamic rampup shot. The toroidal field will
have a small ramp on many shots to enable GPC edge pedestal measurements.

The goal of the second half of the day is to obtain a complete set of edge
profiles with all available diagnostics over a range of conditions. A
consistency check will then be carried out between overlapping diagnostics. We
wish to get data from ohmic, L-mode, ELMfree H-mode, and EDA H-mode plasmas.
Small scans of the outer gap may be used to increase the resolution of some
edge diagnostics. The TF will have a small ramp to enable GPC edge pedestal
measurements. Small amounts of neon puffing may be required to enhance edge
xray signals in ohmic and L-mode plasmas.
Mar 4 1999 08:19:30:810AMRobert GranetzEngineering Setup for Thursday, 990304:

Overnight ECDC in deuterium

**Please install neon gas bottle in place of hydrogen bottle (need adapter).

Load engineering from 990303001.

TF under hybrid control

Gas setup - fill B-top with 6 psi of D2 Hybrid enabled
fill B-side lower with 1 psi of Ar Hybrid DISABLED
fill B-side upper with 2 psi of Ne Hybrid DISABLED(yes, neon)
fill C-side with 30 psi of D2 Hybrid enabled
fill J-bottom with 2 psi of Kr Hybrid DISABLED

The following gate valves should be enabled, assuming no vacuum problems:

ECE, VUV
******* Note: overnight ECDC was actually done in helium, not deuterium as requested.
Mar 4 1999 09:49:48:983AM990304002Robert GranetzShot 02 -- Plasma. 0.8 MA steady-state. Long EDA H-mode. Good xray pedestal
data.

Next shot: load the up/down 0.8 MA ramping shot.
Mar 4 1999 10:23:30:403AM990304003Robert GranetzShot 03 -- Plasma. Good 0.8 MA up/down ramping shot. Peak-to-peak variation
of Ip is about 70 kA, which is somewhat less than the 100 kA
variation that we asked for. Xray pedestal widths definitely show
a difference between + and - dIp/dt. Difference is consistent with
dependence seen a year ago.

Next shot: load the 1.0 MA steady-state shot.
Mar 4 1999 10:22:41:467AM990304004Robert GranetzShot 04 -- Plasma. Good 1.0 MA steady-state shot. EDA H-mode from t=0.75 to
1.1 s. Widths were reasonably constant, but not as steady as at
0.8 MA.

Next shot: load the 1.0 MA oscillating shot.
Mar 4 1999 10:28:08:090AM990304005Robert GranetzShot 05 -- Fizzle.
Mar 4 1999 10:46:00:293AM990304006Robert GranetzShot 06 -- Fizzle.
Mar 4 1999 11:13:44:513AM990304007Robert GranetzShot 07 -- Plasma. Good 1.0 MA oscillating shot. EDA H-mode from t=0.62 to
1.2, with a short L-mode at 1.02 s. Outboard pedestal width varies
with dIp/dt as expected. Top width is not as clear.

Next shot: try 1.2 MA steady-state
Mar 4 1999 11:33:50:750AM990304008Robert GranetzShot 08 -- Plasma. Good 1.2 MA steady-state shot. Prf=1.0 MW. Two long EDA
H-modes (close to being ELMfree). Edge xray emissivity amplitude
increases with plasma current. The outboard width is noticeably
narrower (1.6 mm) than at lower currents, as expected.

Next shot: try 1.2 MA oscillating shot.
Mar 4 1999 11:50:42:763AM990304009Robert GranetzShot 09 -- Plasma. Good 1.2 MA oscillating shot. Prf=1.0 MW. Two long EDA
H-modes. The xray pedestal widths didn't show much dependence on
dIp/dt at this current.

Next shot: retry the 0.8 MA oscillating shot, except put in some
neon to enhance the edge xray signals.
Mar 4 1999 12:16:24:670PM990304010Robert GranetzShot 10 -- Plasma. Good 0.8 MA oscillating shot, but some of the magnetics
data acquisition was corrupted, resulting in problems for EFIT.
Also, there was only one short H-mode (1.0-1.2 s).

Next shot: repeat with no changes.
Mar 4 1999 12:39:48:967PM990304011Robert GranetzShot 11 -- Plasma. Good 0.8 MA oscillating shot, but again there was only one
short H-mode.

Next shot: do a dynamic Ip ramp from 0.8 to 1.1 MA, with a B-field
bump at the 0.8 MA level and another B-field bump at the 1.1 MA
level. Also: no neon puff.
Mar 4 1999 12:50:33:543PM990304012Robert GranetzShot 12 -- Plasma. Good dynamic Ip ramp, but there were no H-modes. RF turned
off at 0.9 s, and Prf=0.9-1.0 MW.

Next shot: repeat, with 10% more RF power.
Mar 4 1999 01:46:44:500PM990304013Robert GranetzShot 13 -- Plasma. Good dynamic Ip ramp, with two H-modes which are at the
times of the Bp bumps. The outboard pedestal width at the higher
current is nearly a factor of 2 less than at the lower current.
HOWEVER, the GPC and TS temperature pedestals show NO difference
at the two currents (0.8 and 1.1 MA) !!! This confirms last year's
findings, but on a single shot.

End of my half of the run day.
Mar 4 1999 01:16:27:200PM990304014Spencer PitcherSecond MiniProposal MP
MP 226 -- Multi-diagnostic characterization of edge

Ohmic 0.4 s to 0.7 s
RF 1 MW 0.7 s to 1.2 s

vertical position scan 2 cm upwards 0.4 s to 0.7 s
vertical position scan 2 cm downwards 0.9 s to 1.2 s

Btor wobbles at approx 0.6 s and 0.9 s

Start at nl04 = 1.0
Mar 4 1999 02:11:44:653PM990304015Spencer PitcherRF cut-off early
no vertical motion
target nl04 = 1.0
Mar 4 1999 03:07:22:640PM990304018Spencer Pitchervertical motion
target nl04 = 1.0
good EDA

Kaiser background shot
Mar 4 1999 03:38:37:670PM990304019Spencer Pitchervertical motion
target nl04 = 1.0
good EDA, identical to shot 18

Kaiser data shot
Mar 4 1999 03:39:05:903PM990304020Spencer Pitchervertical motion
target nl04 = 0.7

fizzle

Kaiser data shot
Mar 4 1999 03:59:25:420PM990304022Spencer Pitchervertical motion
target nl04 = 0.7


Kaiser background shot
Mar 4 1999 04:14:12:950PM990304023Spencer Pitchervertical motion
target nl04 = 1.3


Kaiser data shot
Mar 4 1999 05:01:29:983PM990304025Spencer Pitchervertical motion
target nl04 = 1.3


Kaiser background shot

Physics Operator Comments
Mar 4 1999 09:30:27:200AM990304001Ron Parker
First shot was a fizzle. Current rose too quickly, probably because walls were pumped out due to overnight ECDC in Helium
instead of deuterium as requested. Increase fill pressure about 20% for next shot .
Mar 4 1999 09:50:13:653AM990304003Ron Parker
Shot 002 was a good shot, even though there was a hesitation in the current rise.
The walls should become loaded, which should slow down the current rise and improve early position.
Mar 4 1999 10:01:42:123AM990304003Ron Parker
This was a good shot, from startup viewpoint. Walls are becoming loaded and fill pressure
may need to be reduced after one or two more shots. Current ramps caused enough outer gap
movement to cause RF to lose coupling and the plasma to fall out of H-Mode.
Mar 4 1999 10:25:17:327AM990304004Ron ParkerAnother good shot, startup remains good. Current was increased to 1 MA.
Mar 4 1999 10:37:01:263AM990304005Ron Parker
This shot was a fizzle. Suspicion is too much fill gas (walls have by now become loaded)
and also that BR was too high at breakdown. Next shot will have fill pressure reduced to about 7 10-5
and BR reduced by .5 mT.
Mar 4 1999 10:56:31:903AM990304006Ron ParkerAlso a fizzle. Maybe overshot on fill gas, from 8.5 down to 6.5. Plasma moved out early.
Fill gas adjusted to give about 7.8 10-5 prefill.

Mar 4 1999 11:03:58:857AM990304007Ron Parker
Success. Parker now leaves for 1 hour and any fizzles during the next hour are
not his responsibility.

Wolfe taking over for Parker.
On shot 7, we almost lost it outside at 18msec. Also, the Br is back to being too negative (-.002)

For shot 8, put back the 24msec on pre-puff, leave Br alone and see if it comes back.
Also, 10 Amps more positive on EF4
Mar 4 1999 11:25:55:450AM990304008Ron ParkerShot 8: Pre-puff to 24msec. EF4 from -1280 to -1270.
Also in seg 2: Load the Ip wire from 990225022, a 1.2MA shot; and Put the first tf waggle at 0.7 instead of 0.5

plasma with H-modes. Wmhd=150kJ during the h-modes. with 1 - 1.2MW of RF
Startup looks good, Br back close to zero at t=0.

Next shot, 1.2MA shot with current oscillations.

Mar 4 1999 11:45:16:640AM990304009Ron ParkerShot 9: Load Ip wire from cmod$models:[mhd.xtomo] shot 1200 ( a 1.2MA with 50ka ramps)
Also, move rcur in by 2mm to increase outer gap ; it now ramps from .666 to .665

plasma, made it all the way through.

Next shot, reload segment 2 from shot 3 and add a Neon puff (pg2) 50msec at .25sec
Mar 4 1999 12:04:29:780PM990304010Ron Parkershot 10: reload segment 2 from 990304003 (800kA oscillating current.) Add a 50msec Ne puff (b-side upper, pg2) from .25 to .30sec
plasma, 1-hmode starting at 1sec.
TRAQ data corrupted, EFIT is garbage. No RF processed data.

We are going to repeat this one.
Mar 4 1999 12:28:28:780PM990304011Ron ParkerShot 11: Repeat of shot 10, hopefully with better H-mode, magnetics data
Parker is back in the room and will be taking over again after this shot.

Camac problems delayed shot.

Shot went as planned. Good startup.
Mar 4 1999 12:49:20:403PM990304012Ron Parker
Shot 12: This will be R. Granetz' penultimate shot. Current plateaus at .8 MA, then rises to 1.2 MA.
Small TF ramp at end of each plateau.

No H Mode. Otherwise shot went as planned
Mar 4 1999 01:09:33:530PM990304013Ron Parker
Repeat of Shot 12, trying to squeeze out a little more RF power.
Shot went well, but RF tripped prematurely during 2nd plateau.
Mar 4 1999 01:51:02:717PM990304014Ron ParkerShot 14: S. Pitcher is now the Session Leader.
RF Pulse now from 0.7 to 1.2. Plasma vertical position ramped up 2 cm between o.4 to 0.7 s,
and down 2cm during 0.9 - 1.2 s. Field ramps during .5 to .6 by 8 kA and down during .6 to .7 s,
repeated beginning at .8 s. Fizzle!
Mar 4 1999 02:09:26:700PM990304015Ron Parker
Shot 15: Set up as in shot 14. Lowered fill pressure about 10%.
Shot ran well but didn't have desired vertical ramp because settings didn't load properly.
Mar 4 1999 02:16:11:670PM990304016Ron Parker
Shot 16. No Alternator, no power supplies, no plasma. Ran through sequence to prevent power
supply problems on next shot.
Mar 4 1999 02:30:08:763PM990304017Ron Parker
Shot did not go because there was no EF4. Engineering Operator Error.

Mar 4 1999 04:00:26:467PM990304018Ron ParkerShot ran as planned. 2 cm vertical motion programmed and executed.
Mar 4 1999 04:01:09:467PM990304019Ron Parker
Shot 19: repeat of shot 18. Shot ran well, identical to Shot 18.
Mar 4 1999 04:02:10:513PM990304020Ron Parker
Shot 20. Target density programmed to 0.7 10**14. Fizzle.
Reduce BR to 0.5mT.
Mar 4 1999 03:57:09:233PM990304021Ron Parker
Shot 21: Shot ran as programmed, BR now 0.5 mT.
Mar 4 1999 04:06:53:780PM990304022Ron ParkerShot 22: Repeat of shot 21. Dropped out of H-Mode early. Startup OK.
Mar 4 1999 04:29:47:170PM990304023Ron Parker
Bring density up to 1.3 10**20. Shot ran as planned, but no H-Mode.
Many retries on RF, almost no flattop.
Mar 4 1999 04:45:41:357PM990304024Ron Parker
Shot 24: Same settings as shot 23. Fizzle!
Mar 4 1999 05:06:17:420PM990304025Ron Parker
Shot 25: Lowered prefill pressure to 7 10**-4. Started up OK. Ran well, but No H-Mode.

Engineering Operator Comments
ShotTimeTypeStatusComment
109:07:25:450AMPlasmaOkno faults/fizzel
209:33:26:653AMPlasmaOkno faults/plasma
309:49:31:013AMPlasmaOkno faults/plasma
410:05:41:293AMPlasmaOkno faults/plasma
510:25:47:153AMPlasmaOkno faults/fizzel
610:42:20:233AMPlasmaOkno faults/dud
710:57:00:090AMPlasmaOkno faults/plasma
811:18:18:140AMPlasmaOkno faults/plasma
911:37:53:577AMPlasmaOknofaults/plasma
1011:59:31:200AMPlasmaOkno faults/plasma
1112:20:41:390PMPlasmaOkno faults/plasma
1212:42:22:170PMPlasmaOkno faults/plasma
1301:05:18:983PMPlasmaOkno faults/plasma
1401:36:57:060PMPlasmaOkNo Faults
1501:51:53:140PMPlasmaOkNo Faults / Plasma
1602:12:20:450PMPlasmaBadOnly a no power shot due to alternator low speed
1702:23:49:437PMPlasmaBadNo EF4, Power supply disabled
1802:38:53:733PMPlasmaOkNo Faults / Plasma
1903:06:19:170PMPlasmaOkNo Faults / Plasma
2003:25:47:513PMPlasmaOkNo Faults
2103:38:38:000PMPlasmaOkNo Faults/ plasma
2204:00:19:170PMPlasmaOkNo Faults / plasma
2304:20:59:717PMPlasmaOkNo Faults / Plasma
2404:43:34:903PMPlasmaOkNo Faults
2504:58:56:560PMPlasmaOkNo Faults / Plasma