Alcator C-Mod Run 1091015 Information

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Miniproposals

Operators
Session leader(s):
Physics operator(s):Robert Granetz
Engineering operator(s):Bill Parkin

Engineering Operator Run Comment
MP527 - H-mode SSEP scans

Session Leader Plans
Entered: Oct 14 2009 03:52:20:347PM
Author: Jerry Hughes

Bake/ECDC in D2 overnight
5.4T run in D2.
1psi Ar enabled, puff at 0.3s, 50ms in length

ICRF: up to 3MW from D+E; keep J in reserve in case needed
Essential diagnostics: Thomson, TCI, ECE, standard bolometry and Lyman
alpha, reflectometry, fast magnetics.
Highly desired diagnostics: passive edge CXRS, Hirex rotation,
divertor probes
Cryopump NOT requested.


A. Discharge development is needed to recover SSEP scan, while
avoiding the trouble row of tiles, and also to promote up-down
symmetry of the equilibrium.


1. Attempt to reproduce the equilibrium of shot 1080125013 (5.4T,
800kA, target nl04=7e19, SSEP jogging twice during flattop). ICRF
will tune D+E at low power (~1--2MW) during 1.3--1.5s.

2. Increase RXL as needed to raise strike point to the 4th tile. 3MW
from D+E from 0.6s to 1.5s. This is an attempt to reproduce density
and temperature pedestal modification observed in 2007-08.

2a.If necessary, adjust ZCUR program to achieve SSEP steps of -4mm,
~0mm, and +4mm.

3. Increase RXU so that triangularity is matched in the LSN/USN
cases. 3MW from D+E from 0.6s to 1.5s.

B. Keep discharge developed for A3. Keep ICRF program. Modify ZCUR to
obtain steady H-mode periods of >200ms (3 per shot), changing SSEP
on each shot to obtain a set of measurements at -6mm, -4mm, -2mm,
+2mm, +4mm, +6mm.

C. Raise Ip to 1MA, nl04 demand to 1e20. Keep ICRF program. Modify ZCUR to
obtain steady H-mode periods of >200ms (3 per shot), changing SSEP
on each shot to obtain a set of measurements at -6mm, -4mm, -2mm,
+2mm, +4mm, +6mm. Try tweaking nl04 if steady H-modes are not
accessible.

D. If steady H-modes were achieved in C, go to 1.2MA and increase nl04
demand to 1.2e20. Modify ZCUR to obtain steady H-mode periods of
>200ms (3 per shot), changing SSEP on each shot to obtain a set of
measurements at -6mm, -4mm, -2mm, +2mm, +4mm, +6mm. Try tweaking
nl04 if steady H-modes are not accessible.

E. If there's enough time, repeat the method in B, C, and D at
Ip=600kA, nl04=6e19.

F. When the clock strikes 4:00, do a series of ZCUR scans at each Ip
that's been successfully tried so far, with ICRF OFF. Insofar as
possible, use divertor probes and plenum pressures to "calibrate"
SSEP.



Physics Operators Plans
Entered: Oct 14 2009 03:26:24:160PM
Author: Robert Granetz

Engineering setup for Thursday 2009/10/15

MP527 - H-mode SSEP scans

Session leaders: J. Hughes
Physics operator: R. Granetz

Overnight: usual ECDC in D2 and 60 C bake

Run will start at 09:00 and end at 17:00.

Power systems as on 1080125013 (5.4T, 0.8 MA, 3MW ICRF, ZCUR stepping up
twice during the H-mode to produce steps in SSEP.

A-coil configuration: +Dtop -Dbot -Jtop +Jbot; Enabled (standard
configuration)

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     as is           Hybrid DISABLED (PG2)   
   fill B-main (C-side)  with 40 psi D2  Hybrid enabled  (PG3)
  leave NINJA            as is           DISABLED

Enable the following gate valves and shutters, assuming no vacuum problems:
  ECE, VUV, Z-bolo
 
Torvac setup: keep gate valves open during PULSE

Specific diagnostics: standard set plus fast magnetics, reflectometry.
Highly desired: HIREX, divertor probes, passive edge CXRS

------------------------------------------------------------------------------
Boronization: no
ICRF Setup: All three transmitters in run-on by 08:30
LH Setup: no
DNB: no
Cryopump: no
------------------------------------------------------------------------------

Run plan: SSEP jogs; Load from 1080125013; recall all magnetics predictors
          in seg 2 to bring them up-to-date.  Zero segs 3 & 4.  Import seg
          1 from Wednesday (1091014019).  (I did all this the day before
          today's run and saved it in /home/granetz/pcs_scratch as shot
          1091015000.)

          Additional info from session leader:

         "This shot needs to be tweaked however. The outer strike should be
          moved out of the tungsten trouble area. Simultaneously, I'd like
          to match the R-positions of the upper and lower x-point. This is
          because of an outstanding concern that, in these SSEP scans,
          triangularity changed when we transitioned from LSN to USN.

          For the first shot though, let's see if we can just repeat
          1080125013. I'll have RF tune on the latter part of the shot"

          See the session leader's run plan in the logbook for detailed
          information.


Session Leader Summaries
Entered: Oct 15 2009 05:05:45:947PM
Author: Jerry Hughes
Here are the data I collected from today's run:

Time Alternator speed (RMP)
---- ----------------------
09:21 814
10:21 924
11:11 ~1200
14:06 814
14:54 1152
15:34 1057

At no point did the alternator obtain full speed. There were no attempts at
shots. On the positive side, I got a lot of email answered.


Physics Operator Summaries
Entered: Oct 15 2009 04:06:42:643PM
Author: Robert Granetz

Run summary for Thursday 2009/10/15

MP527 - H-mode SSEP scans

Session leader: J. Hughes
Physics operator: R. Granetz

Today's run was scrubbed due to the recurring problem with the torque transfer control on the
2000 HP motor on the generator.  The generator never made it past speed 3.  Work was carried out
all day to try to solve the problem, but as of the close-of-business today, the problem had not
been resolved.  Work will continue tonight on this problem.

Scorecord:  0 plasmas
            0 duds
            0 fizzles
            0 power supply tests
            0 no-power MDS shot cycles
           --------------
   Total:   0 shot cycles

Session Leader Comments
Oct 15 2009 04:09:07:673PM1091015001Jerry HughesRun is delayed due by alternator issues. It had slowed down to ~770RPM but
looks like it is starting to spin back up.
Actually, as of 9:21 it looks like its frozen at 814.

_______

10:21 924 RPMs and rising.

_______


11:11 Got up to ~1200 RPM then dropped back down to the 800s

_______

12:08 Up and down again. There is a report that the alternator will be delayed
>=2 more hours.

_______

14:06 Sitting at 814 RPM.

_______

14:54 1152 and rising

_______

15:34 1057RPM and rising. It's like we're watching the Dow.


_______

16:08 While I was napping, the run was finally scrubbed.






Physics Operator Comments
Oct 15 2009 09:24:26:760AMRobert Granetz
Loaded saved shot 1091015000 from /home/granetz/pcs_scratch.  See comment under PO_PLAN for details of
the setup.

Oct 15 2009 09:25:47:620AMRobert Granetz
The start of the run is delayed due to a recurring problem bringing the alternator up to speed.
Problem is with transfer to speed 3 (again).  

Engineering Operator Comments
ShotTimeTypeStatusComment