Alcator C-Mod Run 1051123 Information

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Miniproposals
Miniproposal:409
Date Filed: 1/19/2005
Title:Phase Space of the Scrape-off-Layer Plasma
First Author:Brian Labombard
Session Leader:Brian Labombard (shots 1-26)

Operators
Session leader(s):Brian Labombard
Physics operator(s):Ron Parker
Engineering operator(s):Sam Pierson,Ed Fitzgerald

Engineering Operator Run Comment
automatically entered by signon - please replace with real comment

Session Leader Plans
Entered: Nov 22 2005 10:14:33:157PM
Author: Brian Labombard
Session Leader Run Plan for 1051123

MP#409 "SOL Phase space studies"

Goals
        Make progress towards completing MP#409 "SOL Phase space studies". The last time we
attempted to work on this MP (1051110), we were also testing a new A-port scanning probe
(carbon head), which did not yield any useful data. This time we will use a standard
molybdenum head. We also hope to dial-up some ohmic H-modes today to look for a change in
SOL flow response at the L-H transition

Shot Sequence Outline
     A. First we will dial-up some standard 0.8 MA lower single null and upper single
     null discharges. This will allow us to cross-check profile and flow measurements made
     on previous runs. 

     B. Then we will attempt to run some 0.8 MA ohmic H-modes using the usual ramp-down
     and ramp-up of the toroidal field (EDA is desired but not expected at the present
     boronization level). Of particular interest is the SOL flow behavior just before
     and just after the L-H transistion. In order to track this bevavior, we may need to
     run many discharges with the probes poking at different times. For reference, we
     will also run some upper-null discharges with the same current and field programming
     to see where they lie in the edge plasma 'phase-space' plot.

     C. Next, we will hold the field fixed at 4 tesla, and map-out that portion of machine
     parameter spaced called for in MP#409, performing a density scan there in LSN and USN
     discharges.

Run Preparation Tasks (for probe diagnostics)
  - Reconfigure A14 and A12 digitizer connections to outer divertor probe
     array according to file: "put_new_fast_refs_2005_mar01.tcl"
  - Execute TCL>@put_new_fast_refs_2005_mar01.tcl
  - Configure ASP bias supplies: PA93 amplifiers ("DC supply") in standard sweep mode,
     "Sweep A" and "Sweep B" set to -200 volts
  - Use IDL code to switch ASP probe triggering and ASP/FMP power supply biases 
     between one of two modes:
       "Scan" mode  - ASP: N,S,E,W electrodes in current mode, "DC supply"
                           Probe scanning three times during shot, 256k samples/channel
                      FMP: OSD**.p0 probes in current mode,  "Sweep B" supply
                           OSD**.p1 probes in current mode,  "DC -" supply
                           OSD**.p2 probes in floating mode, "DC +" supply
       "Dwell" mode - ASP: W & S electrodes in current mode, "Sweep A" & "Sweep B"
                           N & E electrodes in floating mode
                           Probe in dwell mode, with 512k samples/channel
                      FMP: OSD**.p0 probes in current mode,  "DC -" supply
                           OSD**.p1 probes in current mode,  "DC -" supply
                           OSD**.p2 probes in floating mode, "DC +" supply
         IDL code: mp409_scan.pro
                       undwell_scan_asp.pro
                       set_asp_pa93_sweep.pro
                       set_fmp_sweep.pro
                    mp409_dwell.pro
                       dwell_scan_asp.pro
                       set_asp_fluctuation_mp409.pro
                       set_fmp_fluctuation_mp409.pro

Run Preparation Tasks (for optical diagnostics)
  - Set integration time on Xybion to 1 ms
  - Connect the following fiber views for the fast diodes
        Outer SOL views 1-3,5,7,9-14,31-40 (total of 21)
        Innerwall SOL views B and C
  - Connect the following fiber views for the CHROMEX
        Outer SOL views 18-22,24-29 (total of 11)
        Innerwall SOL views A,D,E,F - otherwise known as 1,4-6
  - Set timing on fastdiode digitizers to 0.1 s after the A-B limiter NINJA puff timing

_______________
Plan A - Standard shots
     Reload from shot#1051110009. This shot ran on segment#2. It was a LSN discharge 
     with Ip=0.8 MA, Bt= 5.4 tesla, NL04 = 0.6e20. Note: segment#3 has
     a USN program that we will use (Segment#4 is double-null? will not be used today.)

     ASP, FSP, ISP programmed to scan at 0.65, 0.85, 1.05 seconds
     NINJA gas puff for GPI and boron V spectroscopy entering plasma at 1.1s
     Set NINJA for D2 puff at A-B limiter and B16-001. Plenum pressure of 10 PSI.

Shots  
1-3  LSN, NL04 = 0.6, Scan mode, optimize probe insertion
     NINJA puff at 1.1 s, fast camera at 1.25 s
4-6  USN (segment #3), NL04 = 0.6, Scan mode, optimize probe insertion
     NINJA puff at 1.1 s, fast camera at 1.25 s

________________
Plan B - Ohmic H-modes
     Reload from shot#1051110017. This was an 0.8 MA discharge with Bt rampdown to 2.9 tesla.
     Set target density to NL04 = 0.60
     Ohmic H-modes started around 1s. 
     NOTE: reprogram ZXL to ramp down relative to present programming by 2 cm,
           starting at 0.7 and ending at 1.4s. This is required to flatten the FSP target location.
     Set probes to scan at 0.55, 0.8 1.05s.

Shots
7-17  Optimize probe insertions and depths to catch L and H phases
      Optional: Run different target densities: NL04 = 0.7, 0.8

      Change to USN (segment#3) and program identical Ip, Bt, NL04 waveforms.
      ZXL programming may need to change on this shot as well.

18-?  Optimize probe insertions and depths to collect data at similar Ip, Bt values as
       ohmic H-mode

________________
If time remains:
Plan C - Begin 4 tesla, 0.8 MA density scan
     Reload from shot#3 above. Program Bt to 4 tesla and NL04 = 0.6

     ASP, FSP, ISP programmed to scan at 0.65, 0.85, 1.05 seconds
     NINJA gas puff for GPI and boron V spectroscopy entering plasma at 1.1s
     Set NINJA for D2 puff at A-B limiter and B16-001. Plenum pressure of 10 PSI.

Shots  
     LSN, NL04 = 0.6, Scan mode, optimize probe insertion
     NINJA puff at 1.1 s, fast camera at 1.25 s
     Set NINJA for D2 puff at A-B limiter and B16-001. Plenum pressure of 10 PSI.

Shots  
     LSN, NL04 = 0.6, Scan mode, optimize probe insertion
     NINJA puff at 1.1 s, fast camera at 1.25 s
     USN, NL04 = 0.6, Scan mode, optimize probe insertion
     NINJA puff at 1.1 s, fast camera at 1.25 s

     USN, NL04 = 0.4, Scan mode
     NINJA puff at 1.1 s, fast camera at 1.25 s
     LSN, NL04 = 0.4, Scan mode
     NINJA puff at 1.1 s, fast camera at 1.25 s

     LSN, NL04 = 0.8, Scan mode
     NINJA puff at 1.1 s, fast camera at 1.25 s
     USN, NL04 = 0.8, Scan mode
     NINJA puff at 1.1 s, fast camera at 1.25 s

     USN, NL04 = 1.0, Scan mode
     NINJA puff at 1.1 s, fast camera at 1.25 s
     LSN, NL04 = 1.0, Scan mode
     NINJA puff at 1.1 s, fast camera at 1.25 s


Physics Operators Plans
Entered: Nov 22 2005 03:00:08:697PM
Author: Ron Parker
Engineering setup for Wednesday 23-Nov-2005

MP 409 SOL Phase Space
Session leader: Labombard
Physics operator: Parker

Overnight ECDC in D2, and bake at 60 C.

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

Power systems as on 1051110009 (0.8 MA, 5.4 T, lower single null)

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 + 2 psi Ne Hybrid DISABLED (PG1)
leave B-side upper as is Hybrid DISABLED (PG2)
fill B-main (C-side) with 40 psi D2 Hybrid enabled (PG3)
Fill NINJA with 10 psi D2, Hybrid disabled

Prepare for between shot boronization, but leave diborane bottle closed to begin.

Enable the following gate valves and shutters assuming no vacuum problems: ECE, VUV, Z-bolo shutters

Torvac setup: Gate valves open

Important Diagnostics:
ASP, FSP, ISP, Xybion camera, fast H-alpha diode array, Chromex, Edge TS

No RF for this run

The purpose of the run will be to expand the collection of SOL Phase Space data.
See details under SL Plan

Session Leader Summaries
Entered: Nov 25 2005 09:53:06:523PM
Author: Brian Labombard
Run Summary for 1051123

MP#409 "SOL Phase space studies"
___________________________________________________________________________________
This was a much more productive run toward the goals of MP#409 than the previous
one on 1051110 - even if we did blow a couple of hours on a between-shot boronization.
The old-style molybdenum probe head on the A-port drive (replacing the shorted-out
carbon probe head) performed well. First we recorded parallel and perpendicular
flows in standard LSN and USN discharges (0.8 MA, 5.4T), with a two-point density
scan. This was to check that the A-port probe was operating the same as other
probes of the same design in previous runs. Then we moved on to ohmic H-modes,
looking to catch recordings of parallel and perpendicular flow profiles in ELM-free
phases. The first two discharge attempts did yield ohmic H-modes, but they were
multiple modes of very short duration - difficult to target with the scanning
probes. So we decided to perform a between-shot boronization: R=75 to 85 cm, 80 cm dwell,
30 minutes, 100% duty cycle. But, because turbo pump #2 was not operating, the
boronization required a manual feedback control of the gas pressure in the torus. Setting
this up caused further delay, leading to a 2 hour time interval before the next discharge
attempt. Naturally the next three shots were fizzles, causing further delay. When we
finally got going again, the ohmic H-modes were only marginally better, if better at all.
Nevertheless, we pushed on, targeting the ELM-free phase as best we could and fine-tuning
the last closed flux surface target position for optimal probe insertion. After many tries,
we did manage to get two good probe insertions into short ELM-free phases (shots 24 and 25).
It's a good thing too because we were cutting it very close; shot#26 was the last plasma
shot of the day and it yielded no addtional scanning probe data during an H-mode phase.
At first glance, the flow data look interesting, with an apparent spatial compression
of the velocity shear layer in H-mode relative to L-mode. However, we still need to
assess if we can trust the inferred flows. In this regard, it would be
beneficial to try to get the 'steep pyramid' probe head (i.e., the carbon probe head)
working on the A-port drive for comparison measurements. Hopefully we can do this before
the present campaign ends. A reversed Bt run would also help here. Meanwhile we learned
something important today: we should perform these ohmic H-mode investigations after a
full boronization. The single between-shot boronization that we performed today
just didn't help.

Interesting side note: John noticed today that as Bt was ramped down in the approach to
ohmic H-mode, the toroidal rotation starts counter-current and ramps to near zero.
The time that the toroidal rotation velocity becomes zero corresponds closely to
the time of ohmic L-H transition. Sound familiar?

Quick shot log:

Ip=0.8MA, Bt=5.4T
1 - LSN, NL04= 0.54 ASP(-5), FSP(-5) E-sweep, NSW-Vf, no ISP
2 - LSN, NL04= 0.60 ASP(+5), FSP(+3) E-sweep, NSW-Vf, ISP - good targeting
3 - LSN, NL04= 0.75 ASP(+6), FSP(+3) SNE-sweep, W-Vf, ISP
4 - LSN, NL04= 0.75 ASP(+7), FSP(+4) SNE-sweep, W-Vf, ISP - good target, ASP deep on scan 2
5 - fizzle
6 - USN, NL04= 0.76 ASP(+3), FSP(-3) SNE-sweep, W-Vf, ISP- over-inserted!
7 - USN, NL04= 0.77 ASP(+3), FSP(-3) SNE-sweep, W-Vf, ISP-excellent
8 - USN, NL04= 0.8 ASP(+9), FSP(+7) SNE-sweep, W-Vf, ISP-excellent
9 - USN, NL04= 0.8 ASP(+10), FSP(+11) SNE-sweep, W-Vf, ISP all excellent targeting
10 - USN, NL04= 0.62 ASP(+10), FSP(+11) SNE-sweep, W-Vf, ISP all excellent targeting

Go to ohmic LSN, H-modes
11 - LSN, NL04= 0.53 ASP(+8?), FSP(+4?) SNE-sweep, W-Vf, ISP (22ms) 0-90 degrees only
First L-H at 1.06s
12 - LSN, NL04= 0.53 ASP(+8), FSP(+2) SNE-sweep, W-Vf, ISP (22ms) 0-90 degrees only
First L-H at 0.93 s Probes catch H-mode on third scan.

Between-shot boronization R=75 to 85 cm, 80 cm dwell, 30 minutes, 100% duty cycle
This took about 2 hours, partially because of TMP2 being off and having to come
up with a work-around for not using the TC gauge on the TMP2 foreline.

13 - fizzle
14 - fizzle
15 - fizzle
16 - LSN, NL04= 0.65 to 0.78 ASP(+6), FSP(+0) SNE-sweep, W-Vf, ISP (16ms)
first L-H at 1.06s
Probes catch short H-mode on last scan
** Note: Boronization has done very little to improve the H-modes **
17 - LSN, NL04= 0.65 to 0.7 ASP(+6), FSP(-2) SNE-sweep, W-Vf, ISP (16ms)
first L-H at 0.98s No scans in H-mode.
18 - LSN, NL04= 0.65 to 0.78 ASP(+6), FSP(-2) SNE-sweep, W-Vf, ISP (16ms)
first L-H at 1.04s. No probe scans in H-mode
19 - LSN, NL04= 0.58 to 0.6 ASP(+8), FSP(+1) SNE-sweep, W-Vf, ISP (16ms)
first L-H at 1s. No probe scans in H-Mode.
20 - LSN, NL04= 0.65 ASP(+7), FSP(+0) SNE-sweep, W-Vf, ISP (16ms)
first L-H at 10.99s. No probe scans in H-Mode.
21 - fizzle
22 - fizzle
23 - fizzle
24 - LSN, NL04= 0.55 ASP(+7), FSP(+0) SNE-sweep, W-Vf, ISP (16ms) Targeting is good.
first L-H at .82s. Second scan catches H-Mode!
25 - LSN, NL04= 0.6 ASP(+7), FSP(+0) SNE-sweep, W-Vf, ISP (16ms)
first L-H at 1s. Third scan catches H-Mode! Great data.
26 - LSN, NL04= 0.6 ASP(+7), FSP(+0) SNE-sweep, W-Vf, ISP (16ms)
first L-H at 1.09s. No probe scans in H-Mode.

Physics Operator Summaries
Entered: Nov 23 2005 05:31:51:800PM
Author: Ron Parker
Physop Summary

This was an ohmic-only run with the purpose being to expand the data base on the edge phase space.

The run went well until shot 12 when boronization was called for. The purpose of the boronization was to encourage ohmic H-modes.

There was some difficulty beginning the boronization due to the fact that the thermocouple used to stabile the pressure was inactive. This caused an unexpected delay of about 45 minutes.

After resuming, the discharge was much more difficult to start up and there were 3 fizzles before it was restored. As usual with boronization, the fill pressure needed careful tuning to find an operating window. Even after a window was found, a period of several fizzles again occured until a pressure was found that allowed 3 more shots. Fortunately, these shots permitted some useful data to be collected.

There was 1 fizzle in 12 shots before boronization, and 6 out of 13 after

Session Leader Comments
Nov 23 2005 09:15:15:320AM1051123001Brian LabombardShot#1 LSN, NL04=0.54, 0.8MA, 5.4T
ASP, FSP scanning at 0..65, 0.85, 1.05s in far SOL


Next: repeat with probes deeper and with ISP
Nov 23 2005 09:29:03:380AM1051123002Brian LabombardShot#2 LSN, NL04=0.6, 0.8MA, 5.4T
ASP, FSP, ISP scanning at 0.65, 0.85, 1.05s
ASP - at separatrix
FSP - first scan at sep.
ISP - good targeting

Next: Repeat with N04=0.8
Nov 23 2005 09:46:04:537AM1051123003Brian LabombardShot#3 LSN, NL04=0.75, 0.8MA, 5.4T
ASP, FSP, ISP scanning at 0.65, 0.85, 1.05s
ASP - could be deeper
FSP - could be deeper
ISP - good

Next: Repeat with probes deeper
Nov 23 2005 09:53:19:430AM1051123004Brian LabombardShot#4 LSN, NL04=0.75, 0.8MA, 5.4T
ASP, FSP, ISP scanning at 0.65, 0.85, 1.05s
ASP - ok
FSP - cok
ISP - good

Next: go to USN
Nov 23 2005 10:29:39:117AM1051123006Brian LabombardShot#6 USN, NL04=0.75, 0.87MA, 5.4T
ASP, FSP, ISP scanning at 0.65, 0.85, 1.05s
ASP - near sep
FSP - far
ISP - over-inserted by 6 mm!

Next: Adjust gaps and Ip
Nov 23 2005 10:40:15:960AM1051123007Brian LabombardShot#7 USN, NL04=0.77, 0.82MA, 5.4T
ASP, FSP, ISP scanning at 0.65, 0.85, 1.05s
ASP - far
FSP - far
ISP - excellent

Next: Adjust outer gap and Ip again
Nov 23 2005 10:53:36:007AM1051123008Brian LabombardShot#8 USN, NL04=0.8, 0.8MA, 5.4T
ASP, FSP, ISP scanning at 0.65, 0.85, 1.05s
ASP - could be deeper
FSP - coudl be deeper
ISP - excellent

Next: Adjust outer gap for Jim with probes deeper
Nov 23 2005 11:03:47:223AM1051123009Brian LabombardShot#9 USN, NL04=0.8, 0.8MA, 5.4T
ASP, FSP, ISP scanning at 0.65, 0.85, 1.05s
ASP - excellent target
FSP - excellent
ISP - excellent

Next: Go to NL04 = 0.6
Nov 23 2005 11:24:02:553AM1051123010Brian LabombardShot#10 USN, NL04=0.62, 0.8MA, 5.4T
ASP, FSP, ISP scanning at 0.65, 0.85, 1.05s
ASP - excellent target
FSP - excellent
ISP - excellent

Next: Go to LSN with Bt ramp-down to get ohmic H-modes
Nov 23 2005 12:28:10:927PM1051123011Brian LabombardShot#11 LSN, NL04=0.53, 0.8MA, 5.4T ramping down to 2.9
ASP, FSP, ISP scanning at 0.65, 0.85, 1.05s
First L-H at 1.06 s
ASP - too far out.
FSP - good targting on first scan
ISP - excellent

Next: Repeat with ZXL ramped down to improve FSP target
Nov 23 2005 02:51:55:093PM1051123012Brian LabombardShot#12 LSN, NL04=0.53, 0.8MA, 5.4T ramping down to 2.9
ASP, FSP, ISP scanning at 0.6, 0.85, 1.08s
First ohmic L-H at 0.93 s
ASP - could be deeper. Last scan in EFH. Evidence of strong perp flows.
FSP - targeting improved
ISP - excellent, but probe only scans 0-90 degrees

Next: Do between-shot boronization
75 to 85 cm sweep, 30 minutes, 100% duty cycle
Nov 23 2005 03:07:20:143PM1051123016Brian LabombardShot#16 LSN, NL04=0.65 to 0.78, 0.8MA, 5.4T ramping down to 2.9
ASP, FSP, ISP scanning at 0.6, 0.85, 1.08s
First ohmic L-H at 1.06
ASP - ok. Last scan in EFH. Evidence of strong perp flows.
FSP - targeting good, last scan is deep
ISP - first two scans ok

Next: Repeat
Nov 23 2005 03:17:35:550PM1051123017Brian LabombardShot#17 LSN, NL04=0.65 to 0.7, 0.8MA, 5.4T ramping down to 2.9
ASP, FSP, ISP scanning at 0.6, 0.85, 1.08s
First ohmic L-H at 0.98
ASP - ok. No scans in H-mode
FSP - targeting good, last scan is deep
ISP - first scan ok

Next: Repeat with inner gap change
Nov 23 2005 03:34:10:737PM1051123018Brian LabombardShot#18 LSN, NL04=0.65 to 0.73, 0.8MA, 5.4T ramping down to 2.9
ASP, FSP, ISP scanning at 0.6, 0.85, 1.08s
First ohmic L-H at 1.04s
ASP - ok, could be deeper. No scans in H-mode
FSP - could be deeper
ISP - could be deeper

Next: Repeat with gap change and probes deeper.
Nov 23 2005 03:46:03:157PM1051123019Brian LabombardShot#19 LSN, NL04=0.58 to 0.6, 0.8MA, 5.4T ramping down to 2.9
ASP, FSP, ISP scanning at 0.6, 0.85, 1.08s
First ohmic L-H at 1s
ASP - ok. No scans in H-mode - missed it again.
FSP - ok
ISP - could be deeper

Next: Repeat with reduced inner gap
Nov 23 2005 03:57:30:207PM1051123020Brian LabombardShot#20 LSN, NL04=0.65, 0.8MA, 5.4T ramping down to 2.9
ASP, FSP, ISP scanning at 0.6, 0.85, 1.03s
First ohmic L-H at .99s
ASP - ok. No scans in H-mode - missed it.
FSP - ok
ISP - ok

Next: Repeat
Nov 23 2005 05:02:09:910PM1051123024Brian LabombardShot#24 LSN, NL04=0.55, 0.8MA, 5.4T ramping down to 2.9
ASP, FSP, ISP scanning at 0.6, 0.85, 1.03s
First ohmic L-H at .82s
ASP - ok. Second scan catches H-Mode! best data today.
FSP - ok
ISP - ok

Next: Repeat
Nov 23 2005 05:04:08:847PM1051123025Brian LabombardShot#25 LSN, NL04=0.6, 0.8MA, 5.4T ramping down to 2.9
ASP, FSP, ISP scanning at 0.6, 0.85, 1.03s
First ohmic L-H at 1s
ASP - ok. Third scan catches H-Mode! Very nice data!
FSP - ok
ISP - ok

Next: Repeat
Nov 23 2005 05:35:19:080PM1051123026Brian LabombardShot#26 LSN, NL04=0.6, 0.8MA, 5.4T ramping down to 2.9
ASP, FSP, ISP scanning at 0.6, 0.85, 1.03s
First ohmic L-H at 1.09s
ASP - ok. No probe scan in H-mode
FSP - ok
ISP - ok

End of run.

Physics Operator Comments
Nov 23 2005 09:03:37:553AM1051123001Ron ParkerFirst shot will be loaded from 1051110009. Startup may need to be touched up.
Nov 23 2005 09:16:17:583AM1051123001Ron ParkerShot 001 went off as programmed. Breakdown a bit late, Bz a bit too negative,reduce by 25 A for next shot.
Nov 23 2005 09:33:48:990AM1051123002Ron ParkerShot 002 ran OK. Next: Raise density to n_eL(4) to 0.8 m-2.
Also reduce fill by 4 ms, set EF 4 current to -1335 from -1325.
Nov 23 2005 09:41:25:117AM1051123003Ron ParkerShot 003 ran OK at n_el(4) at 0.8 m-2.
Need to run shot again, no changes.
Nov 23 2005 09:53:33:257AM1051123004Ron ParkerShot 004 ran OK.
Now for something new: upper single null on next shot.

Also reduce gas by 2 ms for earlier breakdown.
Nov 23 2005 10:06:09:100AM1051123005Ron ParkerShot 005 fizzled -- why? Prefill was slightly lower than in shot 004 and breakdown was very late. We'll put back 3 ms on next shot.
Nov 23 2005 10:31:43:677AM1051123006Ron ParkerShot 006 ran but current reached 900 kA instead of programmed 800.
Also inner gap was only 7 mm and we want 13, so clearin was increased by 6 mm.
With fixed Rcur this will also reduce outer gap by 6 mm.
Nov 23 2005 10:40:57:413AM1051123007Ron ParkerShot 007 ran well, current was a bit high so we'll reduce by 20 kA for next shot.
Breakdown was at ~ 5 ms. Also, right gap will be increased by 2 mm (Rcur decreased by 1mm and flattened.)


Nov 23 2005 10:50:51:850AM1051123008Ron ParkerShot 8 ran well. Outer gap decreases by ~ 3 mm from 1 to 1.3 s. We'll try to take this out on next shot. Otherwise no change.

Nov 23 2005 11:01:46:787AM1051123009Ron ParkerShot 9 ran OK. Next: Lower density, to n_el(4)=0.6e20 m-2.
Nov 23 2005 11:23:28:663AM1051123010Ron ParkerShot 10 ran well, data look good.

Next: Back to LN, 800 kA, H-mode by ramping field down to ~ 2.7 T.
Nov 23 2005 11:39:12:897AM1051123011Ron ParkerShot 11 ran well with intermittent H-modes.

Next: lower X-point seems to drift up during shot. We'll try to correct
out on next shot.
Nov 23 2005 02:05:07:617PM1051123012Ron ParkerShot 12 ran well, landing a little softer.

H-mode not steady enough, so we are shutting down for a light boronization.

This means a delay of about 1 hour before next shot.

Boronization was delayed due to inoperative TC gauge normally used to control pressure. Work around was to control open loop. Total delay looks like 1.5 hours.

Boronization follows procedure used on 11/21/05: 10% deuterated diborane, 90% helium 30 minutes, 100% duty factor, scan 75, 80 dwell, 85 cm

We will also tune the vertical position and outer gap to allow probe to reach proper depth.

We'll start the shot when the base pressure reaches 2e-6 Torr
Nov 23 2005 02:22:32:657PM1051123013Ron ParkerShot 13 was a fizzle, not unexpected.

touch up the error fields on next shot, although breakdown was good.
Nov 23 2005 02:26:31:307PM1051123014Ron ParkerShot 14 also fizzled, breakdown also was somewhat later than in shot 13.
Now we'll start to reduce pressure, 2 ms at a time (to 29 ms on next shot)
Nov 23 2005 02:39:41:063PM1051123015Ron ParkerShot 15 also fizzled, although breakdown was reasonable.
Next: Gas reduced to 27 ms.
Nov 23 2005 03:18:14:847PM1051123016Ron ParkerShot 16 ran well.
Nov 23 2005 03:20:09:423PM1051123017Ron ParkerShot 17 ran OK, but clearin change did not get loaded. Intermitttent H-mode.
Nov 23 2005 03:44:21:987PM1051123019Ron ParkerShot 19 wasn't bad, more sustained H-mode near end.

Next: reduce gas to 25 ms. Also Clearin reduce by 1 mm across the board.
Nov 23 2005 04:02:57:470PM1051123020Ron ParkerShot 20 went off OK, H-mode sustained at end.
Nov 23 2005 04:05:11:157PM1051123021Ron ParkerShot 21 fizzled. Cell access to close diborane valve before next shot
Nov 23 2005 04:24:29:720PM1051123022Ron ParkerShot 22 fizzled. Good breakdown, maybe needs more gas? Bring gas back to 27 ms from 25.
Nov 23 2005 04:39:37:173PM1051123023Ron ParkerAnother fizzle. Good breakdown, but current won't take off.

Keep trying. Add 2 more ms to gas, bringing it to 29 ms. Reduce Br by 0.2 mT
Nov 23 2005 04:45:05:627PM1051123024Ron ParkerShot 024 finally went, H-modes intermittent. It appears that increased gas helps by slowing down current rise.
Nov 23 2005 04:56:33:063PM1051123025Ron ParkerShot 25 went off OK. Again, intermittent H-modes.

Engineering Operator Comments
ShotTimeTypeStatusComment
109:05:11:647AMPlasmaOk
209:19:50:333AMPlasmaOk
309:34:10:960AMPlasmaOk
409:46:43:223AMPlasmaOk
509:59:35:723AMPlasmaOk
610:12:36:070AMPlasmaOk
710:29:47:380AMPlasmaOk
810:42:39:787AMPlasmaOk
910:55:37:617AMPlasmaOk
1011:08:28:303AMPlasmaOk
1111:22:55:553AMPlasmaOk
1211:39:52:787AMPlasmaOk
1302:05:12:973PMPlasmaOk
1402:19:15:693PMPlasmaOk
1502:32:05:873PMPlasmaOk
1602:44:53:970PMPlasmaOk
1703:05:21:207PMPlasmaOk
1803:18:16:550PMPlasmaOk
1903:32:06:877PMPlasmaOk
2003:45:14:860PMPlasmaOk
2103:58:20:860PMPlasmaOk
2204:13:56:190PMPlasmaOk
2304:27:39:877PMPlasmaOk
2404:40:32:393PMPlasmaOk
2504:53:41:907PMPlasmaOk
2605:06:30:547PMPlasmaOk