| Session Leader Plans |
| Entered: Mar 3 2005 10:40:48:403AM |
| Author: Brian Labombard |
Run Plan for 1050303
MP#323 - 2005 campaign
"Scoping Experiments for Upper Divertor Cryopump Operation in Unbalanced Double-Null
H-mode Discharges
Purpose
The purpose of these experiments is to assess the performance of a
cryopump located in the upper divertor and to provide guidance for optimizing the
tile and baffle structures at the entrance to the pumping chamber. In particular,
we wish to make use of the new 'simulated divertor baffles' that were recently
installed in the upper divertor region.
Goals
Of particular interest are near double-null H-mode discharges at low to
moderate densities. These will produce the lowest neutral densities in the upper
chamber and therefore present the biggest challenge for the cyropump system. On
the other hand, these discharges also tend to have a correspondingly lower inventory
of D2 in the vessel. Consequently, a reduced pumping throughput may still be adequate.
Thus, we need to focus on at least two aspects: (1) the active D2 inventory in
the vessel that is required for these discharges and (2) the neutral pressures
in the upper chamber, at the entrance to the cryopump ductwork. Based on recent
experiments, it appears that the neutral pressures under the simulated
divertor baffle also depends on upper strike-point location - something we should
watch carefully again.
Another important piece of information is the effective neutral conductance
between the ductwork and the plasma. We know that 'plasma plugging' can enhance
the neutral pressure in volumes in contact with the plasma; neutrals can partially
reflect off the plasma (via charge exchange). In the case when the flux of neutrals
into the ductwork is balanced by a flux of cold neutrals diffusing through a cold
plasma region, the neutral pressure in the duct can be enhanced. Although a high
neutral pressure at the ductwork entrance is desirable, we also want a high neutral
throughput when the pump is turned on. Thus, a 'neutral diffusion' zone may actually
interfere with the goal of high mass throughput - the effective conductance
(flow rate/pressure drop) might be too low. Therefore another goal of this run is
to (3) characterize the effective neutral conductance into the 'gas box' formed
by the simulated cryopump baffle. Here we will draw on a technique developed for
MP#313, "Instrumented Divertor Leakage Experiment", where a known D2 flow rate was
injected via gas capillaries into various 'gas-box' volumes. The resultant change
in pressure in the volume tells us something about the effective neutral conductance
out of that volume (which must balance the neutral conductance into that volume, the
quantity of interest).
Gas setup
B side-upper: 10 psi D2
C-side: 30 psi D2
B-Top: 6 psi D2
J-Bottom: 30 psi D2
NINJA: 20 psi D2
---------------------------------------
Shot Plan
---------------------------------------
All discharges will be run with the pumping stack gate valves closed
(this is now standardly done).
A. Gas Input Calibration, Shots 1 & 2 --------------------------------------------
Here we want to cross-check the gas input measurements (i.e., measurements of
D2 torr-liters/s through piezo valves and NINJA) with measurements of residual D2 gas
in the chamber.
Setup: Load preprogrammed, pulsed gas waveforms from 1021002005, leading to the
following pulse times
B side-upper: -1 sec, 0.0 sec pulse length, 10 psi D2
C-side: 1 sec, 0.1 sec pulse length, 30 psi D2
B-Top: 3 sec, 0.5 sec pulse length, 6 psi D2
J-Bottom: 5 sec, 0.5 sec pulse length, 30 psi D2 - may not be available?
NINJA: ABLim 7 sec, 0.1 sec pulse length, 20 psi D2
NOTE: DISABLE FIZZLE DETECTOR!
Take two gas-only shots
Change to New NINJA Gas Setup -----------------------------------------------------
Change NINJA D2 pressure to 10 PSI (500 torr)
Reprogram NINJA: ABLim Time1: 0.2 s, with 1.8s duration
Time2: 2.2 s, with 1.8s duration
Note: if this causes too much of a density rise, the pulse lengths may need to
be shortened
Setup for 1 MA, 5.4 tesla plasmas with SSEP control ------------------------------
Near double-null discharge under SSEP control, similar to 1031211007
Ip = 1.0 MA, Bt = 5.4 tesla, NL04 ~ 0.9e20.
Gaps at 1.5 cm
Program RF for 2MW total from 0.7 to 1.4 s.
B. SSEP scan at fixed density, NL04 = 0.9e20 -------------------------------------------
Shots 3,4
SSEP at -0.8 cm
No NINJA puffing
Try to get reproducible H-modes
Shots 5,6
SSEP at -0.5 cm
Shots 7,8
SSEP at -0.3 cm
Shots 9-12
SSEP at -0.3 cm
=> Puff gas to estimate effective neutral conductances
Alternate between NINJA puffing through ABLim, E-Top, and BC-Top capillaries
Try to get matched discharges with different puffing locations
Steady H-modes desired
Shots 13,14
SSEP at -0.1 cm
No NINJA puffing
C. Density scan at fixed SSEP, SSEP = -0.3 cm -------------------------------------------
Shots 15,16
NL04 = 0.8e20
Shots 17,18
NL04 = 0.7e20
Shots 19,20
NL04 = 1.0e20
Shots 21,22
NL04 = 1.1e20
|
| Session Leader Summaries |
| Entered: Mar 3 2005 10:11:44:170PM |
| Author: Brian Labombard |
Run Summary for 1050303
MP#323 - Scoping Experiments for Upper Divertor Cryopump Operation in Unbalanced
Double-Null H-mode Discharges
______________________________________________________________________________
Although the RF power was limited to ~1MW today (E antenna operating, D not
operating, J at 50MHz and just coming up in power), we decided to push ahead
and collect some non- H-mode data in support of assessing the performance of
an upper cryopump. This was good decision. The run went well and we made good
use of the discharges, particularly some 'matched' ohmic discharges
described below.
Shot 1 was a gas input calibration shot. Gas was puffed through PG3, PG4, and
NINJA systems. This will facilitate a cross-calibration using pressure rises in
the vessel (gate valves closed) as compared with pressure drops in those
gas-injection plenums.
Following a couple of shots with SSEP ~ -0.7 cm (#4, #5) we stuck to
SSEP ~ -0.3 cm the rest of the day. RF power from the E antenna (~1 MW level)
was injected from 0.7 to 1.4s, then later from 0.9 to 1.4s (J injected after
this time) until shot #9 when it was turned off for the rest of the day,
per request of the session leader. The decision to turn of the RF was prompted
by the observation of some pressure jumps on the Penning gauges when the RF
turned on. Since there was insufficient RF to get H-modes, the RF was not
helping this MP to reach its goals.
In the remainder of the run, attention was turned to getting detailed pressure
measurement data at two density values, nominally NL04 ~ 0.95 and ~0.75.
These discharges with SSEP ~-0.3 are just about at the optimum magnetic
configuration for sending high heat fluxes to the lower divertor while
maintaining high upper divertor pressures - therefore worth a thorough
investigation. Calibrated gas puffs though capillaries in the upper divertor
(BC-top, E-top), lower divertor (B-bottom, BC-bottom) and elsewhere (A-B Limiter,
inner wall) as 'baseline' shots. Unfortunately, the hand valve to the
BC-bottom capillary was closed, causing us to waste shot #12 and to give up
on this capillary until late in the run when the hand valve problem was
discovered and corrected. We managed to take some make-up shots with BC-bottom
near the end of the run, although matched 'baseline' shots for the highest
density in this series may be lacking.
From these data, we should be able to extract:
(1) the active gas inventory in the vessel (torr-liters injected and
torr-liters remaining in vessel)
(2) the upper and lower divertor pressures, sensitivity of cryopump
baffle pressure to upper secondary strikepoint location
(3) gas conductance into various volumes: cryobaffle, E-top 'slot'
and under lower divertor (BC-bottom).
Quick shot summary
1 - gas calibration
2 - dud
3 - SSEP~ 0.0, NL04 ~ 0.78
4 - SSEP~ -0.7 cm, NL04 ~ 0.78
5 - SSEP~ -0.7 cm, NL04 ~ 0.86
6 - Fizzle
7 - SSEP~ -0.3 cm, NL04 ~ 0.94
8 - SSEP~ -0.3 cm, NL04 ~0.85
The following were 'matched discharges' with calibrated gas injections
NL04 ~ 0.9
9 - NL04=0.86 - baseline, puff from ABLim (10 PSI NINJA)
10 - No plasma shot. Puffing through CB-top - good shot for calibration.
11 - NL04=0.86, puff from B-C top
12 - NL04=0.86, no NINJA puff (BC-bottom capillary valve shut!)
13 - NL04=0.88, puff from E-top
14 - NL04=0.91, from B-bottom
15 - NL04=0.92 - baseline, puff from B16-001 (inner midplane)
NL04 ~ 0.75
16 - NL04 = 0.8, puff from B16-001 (inner midplane)
NINJA puff too large , fueling discharge
=> change to 6 PSI NINJA
17 - NL04=0.76 to .8, puff from B16-001 (inner midplane)
18 - NL04=0.75 to .78, puff from BC-top
19 - NL04=0.76, puff from E-top
20 - NL04=0.78, baseline, puff from ABLim
Stop to fix BC-bottom
21 - Early disruption, Puffing through BC-bottom => working now
NL04 ~0.75
22 - NL04=0.76, puff from BC-bottom
23 - NL04=0.75, ouff from BC-top
NL04~1.0
24 - NL04=0.97 to 1.0, puff from BC-bottom (10 PSI NINJA)
25 - NL04=0.95 to 0.9, puff from BC-top (10 PSI NINJA)
|
| Session Leader Comments |
| Mar 3 2005 12:19:28:120PM | 1050303001 | Brian Labombard | Shot 1 Gas input calibration shot with PG3, PG4, and NINJA
Data look ok
Next: plasma attempt
|
| Mar 3 2005 12:50:42:997PM | 1050303003 | Brian Labombard | Shot 3 1 MA, 5.3 tesla, NL04=0.86, double-null
Upper Penning reads about 3 mtorr
Next: go to SSEP = -0.8 cm
|
| Mar 3 2005 01:30:40:620PM | 1050303004 | Brian Labombard | Shot 4 1 MA, 5.3 tesla, NL04=0.78
SSEP ~ -0.7 cm
Upper Penning reads about 0.8 mtorr
E-top 1.5 falling to 0.8 mtorr
23 torr-liters in
6 torr-liters out
Next: go to NL04= 0.9
|
| Mar 3 2005 01:46:59:573PM | 1050303005 | Brian Labombard | Shot 5 1 MA, 5.3 tesla, NL04=0.86
SSEP ~ -0.7 cm
Upper Penning reads about 2, jumper to 4 mtorr when RF turns on
E-top 4, jumping to 6 mtor when RF turns on
29 torr-liters in
16 torr-liters out
Next: go to SSEP ~ -.5 cm, delay RF turn on to 0.9 s
|
| Mar 3 2005 02:14:28:887PM | 1050303007 | Brian Labombard | Shot 7 1 MA, 5.3 tesla, NL04=0.94
SSEP ~ -0.3 cm
Upper Penning ramping to 10 mtorr
E-top 12, ramping down to 6 => sensitive to upper strike point location
28 torr-liters in
17 torr-liters out
Next: Ask for NL04=0.5, Set up for NINJA puffing through ABLim
|
| Mar 3 2005 02:19:29:653PM | 1050303007 | Brian Labombard | Shot 7 1 MA, 5.3 tesla, NL04=0.94
SSEP ~ -0.3 cm
Upper Penning ramping to 10 mtorr
E-top 12, ramping down to 6 => sensitive to upper strike point location
28 torr-liters in
17 torr-liters out
Next: Ask for NL04=0.85
|
| Mar 3 2005 02:30:44:247PM | 1050303008 | Brian Labombard | Shot 8 1 MA, 5.3 tesla, NL04=0.85
SSEP ~ -0.3 cm
Upper Penning ramping to 6 mtorr
E-top 6, ramping down to 3 => sensitive to upper strike point location
20 torr-liters in
11 torr-liters out
Next: Setup NINJA to puff through ABLim - baseline shot
No RF for the next few shots. We are going to try to produce a set of ~5 identical
ohmic plasmas with known gas puffing rates through capillaries at a number of
locations: ABLim (baseline), BC-top, E-top, BC-bottom, B-bottom
|
| Mar 3 2005 02:58:52:230PM | 1050303009 | Brian Labombard | Shot 9 1 MA, 5.3 tesla, NL04=0.86
SSEP ~ -0.3 cm
Calibrated puff from ABLim
Upper Penning ramping to 9 mtorr
E-top 9, ramping down
43 torr-liters in
34 torr-liters out
Next: Puff from B-C top capillary
|
| Mar 3 2005 03:39:59:260PM | 1050303011 | Brian Labombard | Shot 11 1 MA, 5.3 tesla, NL04=0.86
SSEP ~ -0.3 cm
Calibrated puff from B-C top
Upper Penning ramping to 15 mtorr
E-top 10, ramping down
41 torr-liters in
32 torr-liters out
Next: Puff from B-C bottom capillary
|
| Mar 3 2005 03:45:41:480PM | 1050303012 | Brian Labombard | Shot 12 1 MA, 5.3 tesla, NL04=0.86
SSEP ~ -0.3 cm
Calibrated puff from BC-bottom
No gas came through capillary
Upper Penning ramping to 5 mtorr
E-top 8, ramping down
23 torr-liters in
13 torr-liters out
Next: Puff from E-top capillary
|
| Mar 3 2005 04:03:33:980PM | 1050303013 | Brian Labombard | Shot 13 1 MA, 5.3 tesla, NL04=0.88
SSEP ~ -0.3 cm
Calibrated puff from E-top
Upper Penning ramping to 9 mtorr
E-top 12, ramping down to 10
39 torr-liters in
31 torr-liters out
Next: Puff from B-bottom capillary
|
| Mar 3 2005 04:11:36:527PM | 1050303014 | Brian Labombard | Shot 14 1 MA, 5.3 tesla, NL04=0.91
SSEP ~ -0.3 cm
Calibrated puff from B-bottom
Upper Penning ramping to 16 mtorr
E-top 13, ramping down to 10
48 torr-liters in
42 torr-liters out
Next: Puff from B16-001 (inner wall) capillary
|
| Mar 3 2005 04:29:09:497PM | 1050303015 | Brian Labombard | Shot 15 1 MA, 5.3 tesla, NL04=0.92
SSEP ~ -0.3 cm
Calibrated puff from B16-001 (inner midplane)
Upper Penning ramping to 16 mtorr
E-top 11, fairly flat
48 torr-liters in
41 torr-liters out
Next: Go to NL04 = 0.7
|
| Mar 3 2005 04:49:00:850PM | 1050303016 | Brian Labombard | Shot 16 1 MA, 5.3 tesla, NL04=0.8 to .86
SSEP ~ -0.3 cm
Calibrated puff from B16-001 (inner midplane)
Upper Penning ramping to 8 mtorr
42 torr-liters in
35 torr-liters out
Next: Repeat with 6 PSI in NINJA plenum
|
| Mar 3 2005 04:58:27:360PM | 1050303017 | Brian Labombard | Shot 17 1 MA, 5.3 tesla, NL04=0.76 to .8
SSEP ~ -0.3 cm
Calibrated puff from B16-001 (inner midplane)
Upper Penning 1.2 mtorr ramping, then jumping up to 4
E-top 2 mtorr and flat
28 torr-liters in
20 torr-liters out
Next: Repeat with puff from BC-top
|
| Mar 3 2005 05:12:30:593PM | 1050303018 | Brian Labombard | Shot 18 1 MA, 5.3 tesla, NL04=0.75 to .78
SSEP ~ -0.3 cm
Calibrated puff from BC-top
Upper Penning 1.8 mtorr ramping, then jumping up (mode jump?)
E-top 2.3 mtorr and flat
25 torr-liters in
16.5 torr-liters out
Next: Repeat with puff from E-top
|
| Mar 3 2005 05:23:03:453PM | 1050303019 | Brian Labombard | Shot 19 1 MA, 5.3 tesla, NL04=0.76
SSEP ~ -0.3 cm
Calibrated puff from E-top
Upper Penning 1.4 mtorr ramping up
E-top 2.3 mtorr and flat
23 torr-liters in
15 torr-liters out
Next: Repeat with puff from ABLim
|
| Mar 3 2005 06:01:18:670PM | 1050303020 | Brian Labombard | Shot 20 1 MA, 5.3 tesla, NL04=0.78
SSEP ~ -0.3 cm
Calibrated puff from ABLim
Upper Penning 1.2 mtorr ramping up
E-top 1.8 mtorr and flat
23 torr-liters in
15 torr-liters out
Next: Repeat with puff from BC-bottom
|
| Mar 3 2005 06:28:00:810PM | 1050303022 | Brian Labombard | Shot 22 1 MA, 5.3 tesla, NL04=0.76
SSEP ~ -0.3 cm
Calibrated puff from BC-bottom
Upper Penning 1.1 mtorr ramping up
E-top 1.5 mtorr and flat
27 torr-liters in
17 torr-liters out
Next: Repeat with puff from BC-top
|
| Mar 3 2005 06:39:27:123PM | 1050303023 | Brian Labombard | Shot 23 1 MA, 5.3 tesla, NL04=0.75
SSEP ~ -0.3 cm
Calibrated puff from BC-top
Upper Penning 1.6 mtorr ramping up
E-top 1.8 mtorr and flat
23 torr-liters in
14 torr-liters out
Next: Go to NL04 = 0.9 with puff from BC-bottom
|
| Mar 3 2005 06:51:01:420PM | 1050303024 | Brian Labombard | Shot 24 1 MA, 5.3 tesla, NL04=0.97 to 1.0
SSEP ~ -0.3 cm
Calibrated puff from BC-bottom (10PSI pressure)
Upper Penning 6 mtorr ramping up to 20
E-top 15 mtorr
57 torr-liters in
52 torr-liters out
Next: Puff from BC-top
|
| Mar 3 2005 07:06:56:077PM | 1050303025 | Brian Labombard | Shot 25 1 MA, 5.3 tesla, NL04=0.95 to 0.9
SSEP ~ -0.3 cm
Calibrated puff from BC-top (10PSI pressure)
Upper Penning 8 mtorr ramping up
E-top 10 mtorr
45 torr-liters in
40 torr-liters out
|
| Physics Operator Comments |
| Mar 3 2005 11:25:46:573AM | | Ian Hutchinson | Start PCS. Load from 1031211007.
Call Ip predictor. Set offset to -70000.
This shot is using segment 4, and ssep control.
Import segment 1, 2, 3 from 1050302029 (last shot from yesterday).
Got timestamp errors for segment 1 p5,10,16. Touched and reloaded.
|
| Mar 3 2005 12:11:03:667PM | 1050303001 | Ian Hutchinson | Because PCS was screwed up. Cancel all PCS and restart.
This got back my settings. Saved in own area.
Loaded from 1021002005. Twiddled things to make the gas
work. It should be just PG3=C-Side=B-main, PG4=B=top plus ninja.
Run gas only shot.
|
| Mar 3 2005 12:32:11:323PM | 1050303002 | Ian Hutchinson | Load back the saved setup from 10001 in my area.
Load into model. This is using segment 1 and segment 4.
Dud. Gas fill was rather low. Br rather low.
Br offset to -.0015 from -.0025
Gas fill puff to 20ms from 17ms.
|
| Mar 3 2005 01:07:25:120PM | 1050303003 | Ian Hutchinson | Plasma. Very close to double null. Slightly upper x-point if anything.
Big injection at 1.17s leads to disruption. Spark appears to come from above the D-port antenna.
Lower the ssep to -8mm from -1mm.
|
| Mar 3 2005 01:39:55:950PM | 1050303004 | Ian Hutchinson | Plasma till rampdown. ssep control worked well.
Raise nl04 demand to .9 from .8.
|
| Mar 3 2005 01:49:48:620PM | 1050303005 | Ian Hutchinson | Plasma to rampdown.
Ssep to -5mm.
|
| Mar 3 2005 01:54:14:450PM | 1050303006 | Ian Hutchinson | Fizzle.
Br offset to -.001T
Rcur offset to 1300A from 1000A.
|
| Mar 3 2005 02:16:49:917PM | 1050303007 | Ian Hutchinson | Plasma.
Rcurr offset to 700A.
Keep ssep setting till later in rampdown.
nl04 to .85
|
| Mar 3 2005 02:54:15:213PM | 1050303008 | Ian Hutchinson | Plasma.
|
| Mar 3 2005 03:07:05:277PM | 1050303009 | Ian Hutchinson | Plasma. Some hard xrays.
Br offset to 500A.
|
| Mar 3 2005 03:39:58:573PM | 1050303010 | Ian Hutchinson | Data system null cycle
|
| Mar 3 2005 03:40:08:683PM | 1050303011 | Ian Hutchinson | Plasma no changes.
|
| Mar 3 2005 03:40:18:090PM | 1050303012 | Ian Hutchinson | Plasma no changes.
|
| Mar 3 2005 04:03:00:463PM | 1050303013 | Ian Hutchinson | Plasma.
|
| Mar 3 2005 04:26:49:277PM | 1050303014 | Ian Hutchinson | Plasma
|
| Mar 3 2005 04:26:59:027PM | 1050303015 | Ian Hutchinson | Plasma
|
| Mar 3 2005 05:41:57:593PM | 1050303016 | Ian Hutchinson | nl04 demand to 0.7
|
| Mar 3 2005 05:42:36:907PM | 1050303020 | Ian Hutchinson | Plasma
Break for cell access.
Br offset to -.0015. It had drifted up.
|
| Mar 3 2005 06:17:19:547PM | 1050303021 | Ian Hutchinson | Br offset at -.0015
Plasma disrupts in ramp-up. Went very resistive. Looks like an impurity problem, perhaps a brick.
|
| Mar 3 2005 06:37:05:983PM | 1050303023 | Ian Hutchinson | Plasma
Raise nl04 demand to 0.9e20.
|
| Mar 3 2005 06:51:38:780PM | 1050303023 | Ian Hutchinson | Plasma
|
