| Miniproposals | ||||||||||
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| Operators | |
| Session leader(s): | Ron Parker,Martin Greenwald |
| Physics operator(s): | Ian Hutchinson |
| Engineering operator(s): | Andy Pfeiffer,Ed Fitzgerald,Bill Parkin |
| Engineering Operator Run Comment |
| MP 515: Effect of launched LH wave n_par spectrum on current profile Ses |
| Session Leader Plans |
| Entered: Aug 2 2007 03:10:48:803PM |
| Author: Martin Greenwald |
| MP 498 Density peaking at low collisionality
The goal is to extend the range of low density H-modes in the nu_eff, q95 plane, That will require Line-AVERAGE densities below 2e20 and current below 1 MA. We're trying to get an early start on tomorrow's run. The plan will be: We will try to follow the approach from 1070614 (which was H-mode cryopump studies.) Shot 13 is a good example of what we're look for. In that run, ssep was scanned from slightly negative to slightly positive - hysteresis and a healthy amount of RF power was sufficient to maintain the H-mode. However we want to avoid control problems associated with the ssep control. An option - to be discussed by operators - is to hold the xpoints fixed and move Zcur. 0. Start with The machine should be boronized. The cryopump should be available Ip = 0.7MA Bt = 5.4 T target nl_04 = 0.6e20 1. Once we have established an approach, try to find the lowest density where H-mode is accessible. 2. Drop Ip to 0.5 MA - scan down in density 3. Drop Ip to 0.4 MA - scan down in density 4. At 0.4 MA - raise density in steps until H-mode is lost 5. Raise Ip to 0.85 MA - scan to lowest density We will want some Argon for HIREX, gas puff for IW CXR, DNB for other CXR |
| Physics Operators Plans |
| Session Leader Summaries |
| Entered: Aug 2 2007 02:31:29:913PM |
| Author: Ron Parker |
| The run was troubled by two problems, one the outside temperature which caused the temperature in the LH HV power supply to exceed its trip set point (preventing the breaker from going in), the other a hot spot on the moly limiter protecting the LH grill. The latter prevented the net LH power to be raised over 400 kW without disruption. Changing n_par to 2.3 did not help, as disruptions still occured due to the hot spot on the moly limiter. The hot spot looked like it was also connected to the other limiter, following field lines. No hot spot occurred without LH power. This is new for the LH and may have been a consequence of the specific plasma shape. During periods of LHRF, decreses in loop voltage were observed at levels consistent with earlier observations. Unfortunately due to the above problems, very little useful data were obtained. |
| Entered: Aug 2 2007 05:21:35:983PM |
| Author: Martin Greenwald |
| We made a good start on tomorrow's run. We can start tomorrow, with the last shot from today. We had 9 shots (20-28), there were a couple of fizzles
The equilibrium was adjusted to scan from slightly LSN to DN/USN. We did not run the cryopump - which we will do tomorrow. The target density was then gradually lowered, nebar reaching 0.8e20 on shot 28 There were problems with radiated power, boronization tonight should help with this as well. Shots of interest were: nebar_target nebar_hmode 1070802021 1.3 1.7 1070802022 1.3 1.8 1070802025 1.2 1.8 1070802026 1.0 1.7 1070802027 1.0 1.5 1070802028 0.8 1.5 |
| Physics Operator Summaries |
| Entered: Aug 2 2007 05:03:43:400PM |
| Author: Ian Hutchinson |
| Summary
We had some PS problems early. Then LH had a problem with overheating of its power supply. After struggling for some time, it was decided to move in the afternoon to the ssep scan with low collisionality. The problem of control and notably loss of control because of EF2 railing was solved by drastically reducing the ICEF4 gain and setting its level to zero. This allows EF2byEF4 to do its job. Scorecard
Shot,Duration(s),Ipmax(MA),Result Shot,Duration(s),Ipmax,Result
| 01 0.000 0.028 Dud | 02 1.987 0.838 Plasma |
| 03 1.137 0.835 Plasma | 04 0.000 0.006 Dud |
| 05 0.000 0.002 Dud | 06 1.991 0.838 Plasma |
| 07 1.991 0.836 Plasma | 08 1.019 0.837 Plasma |
| 09 0.000 0.041 Fizzle | 10 1.010 0.839 Plasma |
| 11 0.000 0.043 Fizzle | 12 1.994 0.843 Plasma |
| 13 1.064 0.838 Plasma | 14 1.993 0.843 Plasma |
| 15 1.994 0.824 Plasma | 16 1.993 0.841 Plasma |
| 17 1.992 0.828 Plasma | 18 1.992 0.841 Plasma |
| 19 1.994 0.834 Plasma | 20 1.980 0.634 Plasma |
| 21 1.977 0.646 Plasma | 22 1.974 0.653 Plasma |
| 23 0.000 0.055 Fizzle | 24 0.000 0.047 Fizzle |
| 25 1.981 0.674 Plasma | 26 1.986 0.680 Plasma |
| 27 1.990 0.676 Plasma | 28 1.987 0.680 Plasma |
Date 1070802: 28 shots. 21 plasmas. 4 fizzles. 3 duds. 0 System Error.
(Plasma = Ip gt 60.0 kA Dud = H_alpha lt 0.40 V)
Total plasma duration: 38.03 s (exceeding -100 kA)
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| Session Leader Comments | |||
| Aug 1 2007 03:20:20:010PM | Ron Parker | Session Leader Plan for Run 1070802
MP 515: Effect of launched LH wave n_par spectrum on current profile Session Leader: R. Parker Physop: I. Hutchinson The purpose of these experiments is to investigate the effect of varying the launched n|| spectrum on the LH-perturbed current distribution in C-Mod plasmas. The measurements will be carried out in both Ohmic and ICRF-heated L-Mode plasmas, as well as in H-Mode plasmas providing suitable low density H-Modes can be produced. Overnight ECDC, usual formula. Power systems as on 1070619 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 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: ECE, VUV, Z-bolo shutters, NB Torvac setup: Gate valves open during pulse. ICRF: E-port ready at beginning of run; also J-port if feasible Starting shot: 1070619008 Following the advice of the EPC, we'll concentrate on n|| scans in the run: Shots 1-5: Establish 800 kA, 5.4 T, 5e19 m-3 discharge. Couple â?¥500 kW LHCD @ n|| = 1.6. Ensure plasma stays in L-Mode with available ICRF power (J-port preferred but if not, E-port is OK), Optimize shape for coupling. Shots 6-10: No ICRH. Obtain good quality MSE and IXS data on shot established in shots 1-5. Shots 11-15: Repeat shots 6-10 with ICRH = 1 MW and higher if available. Shots 16-20: Couple â?¥500 kW LHCD @ n|| = 2.3. No ICRH. Obtain good quality MSE and IXS data. Shots 21-25: Repeat shots 16-20 with 1 MW and higher if available, avoiding H-Mode. Shots 25 - end of run: Repeat above shot sequence beginning with shot 16, with n|| = 3.1. Note: If ICRF part of plan is unproductive, stick with Ohmic and increase n to 8e19 m-3. | |
| Aug 2 2007 09:00:25:350AM | 1070802001 | Ron Parker | First shot: Dud, no EF2 |
| Aug 2 2007 10:07:26:147AM | 1070802002 | Ron Parker | Shot 2 ran, but LH tripped due to filament fault. Problem was in the "readback" circuit. The fault sensor will be bypassed. |
| Aug 2 2007 11:00:42:100AM | 1070802006 | Ron Parker | Shot 6 ran well with LH, delta V ~ 0.4 V. |
| Aug 2 2007 11:01:19:740AM | 1070802007 | Ron Parker | Shot 7 OK, full length LH w/o fault. |
| Aug 2 2007 11:29:55:007AM | 1070802008 | Ron Parker | Shot 8 disrupted. |
| Aug 2 2007 12:09:41:600PM | 1070802012 | Ron Parker | We are having temperature problems in the LH power supply -- T has reached 120 deg and this prevents closing the breaker. Shot 12 was a shot w/o LH. George is trying to cool things down by installing additional fans. |
| Aug 2 2007 03:07:37:110PM | 1070802021 | Martin Greenwald | We're getting an early start on tomorrow's run - mostly discharge development.
First shot in the series had a short H-mode, ssep probably went more positive than we want for the available power. The density drooped appropriately... |
| Aug 2 2007 03:23:28:240PM | 1070802021 | Martin Greenwald | H-mode was longer, but temperatures and stored energy are still quite low.
Ip ~ 0.6 MA nebar ~ 1.8-1.6 in H-mode |
| Aug 2 2007 03:31:21:530PM | 1070802022 | Martin Greenwald | ICRF moved to 0.5 seconds to provide heating while topology is still LSN.
A fairly weak h-mode from 0.53 to 0.9 seconds |
| Aug 2 2007 03:41:03:197PM | 1070802023 | Martin Greenwald | fizzle |
| Aug 2 2007 03:52:14:850PM | 1070802024 | Martin Greenwald | fizzle - leak? |
| Aug 2 2007 04:39:44:890PM | 1070802026 | Martin Greenwald | H-mode, with a dropout early
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| Aug 2 2007 04:41:32:640PM | 1070802027 | Martin Greenwald | Multiple h-modes and RF trips |
| Aug 2 2007 05:04:28:260PM | 1070802028 | Martin Greenwald | Multiple H-modes again, but probably the best performance today.
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| Physics Operator Comments | |||
| Aug 2 2007 08:55:53:423AM | Ian Hutchinson | Load from 1070619008.
Need to call all predictors. Load got wolfe's new complaint. Import segment 1 from 1070801032. Call zeroed ssep, wire 11. Not obviously broken. Loaded | |
| Aug 2 2007 09:02:18:773AM | 1070802001 | Ian Hutchinson | Dud. No EF2 operator error. |
| Aug 2 2007 10:28:19:140AM | 1070802003 | Ian Hutchinson | Raised plasma zcur by 0.5cm and zxl by 0.5cm at LH request.
Disrupts at 1.1s. Not obvious why. There is a position problem but there's a lot else going on too. A-coil is misbehaving. Apparently there's a locked mode. Also EF2U appears to single-phase, forcing strange currents in other coils. Power supply checks and tests. Add 100ms to Bt and Ip flat top. Move zxu up to 6cm from 5cm. Fill puff to 20ms. Load |
| Aug 2 2007 10:28:27:297AM | 1070802004 | Ian Hutchinson | PS test |
| Aug 2 2007 10:28:37:077AM | 1070802005 | Ian Hutchinson | PS test. |
| Aug 2 2007 11:00:15:943AM | 1070802006 | Ian Hutchinson | Plasma. |
| Aug 2 2007 11:14:50:723AM | 1070802007 | Ian Hutchinson | Plasma.
Extend TF pulse to 2.2 sec because of coax worries. Increase Rcur offset to 1400 from 1200 to increase Bz ramp rate. |
| Aug 2 2007 11:28:08:863AM | 1070802008 | Ian Hutchinson | Plasma disrupts at 1s following a big injection at 0.98s.
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| Aug 2 2007 11:43:21:850AM | 1070802009 | Ian Hutchinson | Fizzle.
Rcur offset returned to 1200. |
| Aug 2 2007 11:53:59:677AM | 1070802010 | Ian Hutchinson | Plasma disrupts at about 1s. Very similar to shot 8. Impurity injection.
Reduce Rcur by .15cm to increase the right gap by 3mm. |
| Aug 2 2007 12:07:13:863PM | 1070802011 | Ian Hutchinson | Fizzle.
Rcur offset to 1000. Fill puff to 18ms. |
| Aug 2 2007 12:22:40:007PM | 1070802012 | Ian Hutchinson | Plasma to rampdown. No LH. |
| Aug 2 2007 12:39:42:137PM | 1070802013 | Ian Hutchinson | Plasma disrupts at 1.05s with LH.
This is a circumstantial demonstration that the disruption is caused by LH. The wide-angle camera sees a bright spot that correlates with the LH. |
| Aug 2 2007 01:01:48:443PM | 1070802014 | Ian Hutchinson | Plasma to rampdown. NO LH.
Move rcur an additional 1.5mm in. Set zxu to +7cm. |
| Aug 2 2007 01:39:51:290PM | 1070802015 | Ian Hutchinson | Plasma to rampdown. LH tripped (new phasing).
Noticed that the segment 1 current demand on Ip is very low .25MA. Imported segment again to prove I did not make an error. Imported 15 segment to get back to where we were. Turn off gain on IP in segment 1. Add back 1.5mm to rcur. RXu to 4cm from 4.5cm. |
| Aug 2 2007 02:08:29:903PM | 1070802016 | Ian Hutchinson | Plasma to rampdown. Very nearly killed by LH radiative event.
Move plasma in by 2.5mm after 1.2s. Lower rxu to 3cm from 4cm. Change of plans. Move plasm in by 5mm for the whole flat top for ICRF. |
| Aug 2 2007 02:23:02:433PM | 1070802017 | Ian Hutchinson | Plasma. Made a mistake and moved out. Seems to be on the limiter.
Put correct rcur setting in. |
| Aug 2 2007 02:32:20:650PM | 1070802018 | Ian Hutchinson | Plasma. ICRF test.
Move plasma out to give LH-suitable gap. Leave in after 1.2s. |
| Aug 2 2007 03:01:03:213PM | 1070802019 | Ian Hutchinson | Plasma to rampdown. LH ran.
Load from Wolfe's DN shot 1070803305. Fill puff to 20ms from 27ms. |
| Aug 2 2007 03:06:34:657PM | 1070802020 | Ian Hutchinson | Plasma.Successfully got the swing from lower to upper null.
Zxu to +.5 from 1.cm decrease the ssep upper null. |
| Aug 2 2007 03:26:34:197PM | 1070802021 | Ian Hutchinson | Plasma.
Lengthen TF pulse to avoid downward glitch. |
| Aug 2 2007 03:40:26:493PM | 1070802022 | Ian Hutchinson | Plasma. RF at .5s.
Tweak x-point positions. Lower NL04 early to try to get better H-modes. Lower zcur to .003 during upper null, SL request. |
| Aug 2 2007 03:54:11:057PM | 1070802023 | Ian Hutchinson | Fizzle.
Fill puff to 18ms. |
| Aug 2 2007 04:06:50:180PM | 1070802024 | Ian Hutchinson | Fizzle. The leak is reported to be worse at present.
Rcur offset to 700 from 900. |
| Aug 2 2007 04:22:06:980PM | 1070802025 | Ian Hutchinson | Plasma to rampdown. Some injections.
Lower nl05 to 5e19. Lower fill puff to 16ms. Set Ar puff to 50ms from 100ms. |
| Aug 2 2007 04:39:17:280PM | 1070802026 | Ian Hutchinson | Plasma to rampdown.
Actually Ar was not enabled. Lower the gas V during the shot to keep the nl04 a bit lower. |
| Aug 2 2007 05:00:46:150PM | 1070802027 | Ian Hutchinson | Plasma to rampdown.
Lower nl04 to 4e19 |
| Aug 2 2007 05:03:12:730PM | 1070802028 | Ian Hutchinson | Plasma to rampdown. |
| Engineering Operator Comments | ||||
| Shot | Time | Type | Status | Comment |
| 1 | 08:58:38:817AM | Plasma | Bad | No TMX |
| 2 | 09:11:16:880AM | Plasma | Ok | |
| 3 | 09:33:19:763AM | Plasma | Ok | |
| 4 | 10:14:22:797AM | Test | Ok | EF2U PLC Test |
| 5 | 10:25:57:607AM | Test | Ok | EFC 800 volts 1000 Amps |
| 6 | 10:36:50:710AM | Plasma | Ok | |
| 7 | 10:54:03:340AM | Plasma | Ok | |
| 8 | 11:11:49:520AM | Plasma | Ok | |
| 9 | 11:24:31:593AM | Plasma | Ok | |
| 10 | 11:37:07:797AM | Plasma | Ok | |
| 11 | 11:50:58:297AM | Plasma | Ok | |
| 12 | 12:05:18:970PM | Plasma | Ok | |
| 13 | 12:20:08:987PM | Plasma | Ok | |
| 14 | 12:41:03:120PM | Plasma | Ok | |
| 15 | 12:55:15:980PM | Plasma | Ok | |
| 16 | 01:30:51:830PM | Plasma | Ok | |
| 17 | 02:04:35:773PM | Plasma | Ok | |
| 18 | 02:17:14:693PM | Plasma | Ok | |
| 19 | 02:29:46:350PM | Plasma | Ok | |
| 20 | 02:48:41:057PM | Plasma | Ok | |
| 21 | 03:05:42:313PM | Plasma | Ok | |
| 22 | 03:21:19:750PM | Plasma | Ok | |
| 23 | 03:35:33:800PM | Plasma | Ok | |
| 24 | 03:49:27:770PM | Plasma | Ok | |
| 25 | 04:04:53:943PM | Plasma | Ok | |
| 26 | 04:20:26:100PM | Plasma | Ok | |
| 27 | 04:36:52:777PM | Plasma | Ok | |
| 28 | 04:55:54:750PM | Plasma | Ok | |
| System Availability | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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