Alcator C-Mod Run 1000616 Information

Back to runs

Miniproposals
Miniproposal:248
Date Filed: 4/15/1999
Title:High Performance Operation
First Author:Earl Marmar
Session Leader:Earl Marmar (shots 1-22)

Operators
Session leader(s):Earl Marmar
Physics operator(s):Robert Granetz
Engineering operator(s):Gary Dekow

Engineering Operator Run Comment
MP #248 High performance - SL: Marmar MP #264 Neutral point disruption

Session Leader Plans

Physics Operators Plans

Session Leader Summaries
Entered: Jul 7 2004 03:49:24:460PM
Author: To Be Determined
Session Leader Run Summary

1000616

MP #248 -- High performance

PO: Granetz
EO: Dekow
SL: Marmar

This was an interesting and reasonably productive run.

We attempted to maximize the stored energy and neutron rate, and then take an
ion temperature profile of a decent shot using HIREX.

The knobs we attempted to use were:

I_p scan from 1.0 to 1.2 MA;
n_e target scans;
puffing during H-Mode.

D&E port were pushed to quite high powers, getting to over 3 MW total on some
shots. Operation at about 3 MW total was fairly reliable.

All shots with both transmitters on had good EDA H-Modes.

Stored energies above 200 kJ at 1.2 MA were obtained on shots 21 and 22.
Stored energy of 192 kJ was obtained on shot 13, which was a nice steady 1 MA
EDA; total RF power was reported in the tree as 3.8 MW, but according to the
RF'ers, was really closer to 3.5 MW.

The last shot (22) had D_2 puffed from C-side during the H-Mode. This may have
helped the RF stay on; the previous 2 attempts at 1.2 MA both had early
transmitter trips. The radiated power also decreased after 1 second on shot 22,
which may be related to the puff. Brian reported that the midplane pressure was
relatively high during the H-mode for this shot. As pointed out by Martin,
there was also some coherent MHD seen on the fast magnetics, in between
sawteeth, which correlates with D-alpha spikes. The energy confinement also
degraded somewhat between 1 and 1.07 s, but then started to recover. The RF
power also drooped slightly after 1 second.

Shots worthy of further analysis
1-5,7-9,12,13,16-19,21,22.

Physics Operator Summaries
Entered: Jul 7 2004 04:37:11:397PM
Author: To Be Determined
Physics operator summary for run 1000616:

MP #248 -- High performance; Session leader: E. Marmar
MP #264 -- Neutral point disruption exp'ts (con't); Session leader: R. Granetz

Physics operator: R. Granetz
Engineering operators: B. Cochran

Summary: The machine ran very well today. All shots ran full length. We ran
plasma currents of 1.0, 1.1, and 1.2 MA at Btor=5.3 and 5.4 T.
Target densities were 1.0-1.5e20 m-2 (nl_04), and H-mode densities
reached nl_04=2.6e20 m-2 on the last shot. There were many shots with
Prf > 3 MW, and peak stored energies ranged from 160-208 kJ. The
RF antennas seemed to like the higher densities. Neutron rates
were typically 3-6e13/s. H/D was 3-4% all day.

We only ran MP #248 -- High performance. We did not switch to the
neutral point MP.

Scorecard: 22 plasmas
0 fizzles
0 duds
0 tests
0 aborted
----------
22 total

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

Engineering setup for Friday, 16 June 2000:

Overnight ECDC in D2, stopping 1-2 hours prior to the run.

Run begins at 9:00 and ends at 17:00.

Power system setup as on 1000613006 (from Tuesday morning), including
fizzle delay settings

Gas setup - fill B-top with 6 psi of D2 Hybrid enabled
fill B-side lower with 1 psi of Ar Hybrid DISABLED
leave B-side upper as is Hybrid DISABLED
fill C-side with 30 psi of D2 Hybrid enabled
leave J-bottom as is Hybrid DISABLED

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

First shot will be a 50 kA TF-only test under PLC control.

-------------------------------------------------------------------------------
Run plan (two different MP's):

MP #248 -- High performance; Session leader: E. Marmar
MP #264 -- Neutral point disruption exp'ts (con't); Session leader: R. Granetz

PO: R. Granetz

The run will begin with MP #248. We will load from 1000615001 (1 MA, 5.3 T,
outer gap=12 mm), but set the density at nl_04=1.1e20 m-2 and load
CLEARIN from 1000613006 (which contains the new offset). RF (from D and E)
will turn on from t=0.8 to 1.5 s, at the highest power possible. We may
increase Ip to 1.1 MA after the first shot. Segments 3 and 4 have been
loaded with a good shot from the neutral point run (1000526022), with CLEARIN
loaded from 1000613006 to get the new offset. We will switch to these segments
for the disruption MP.

After a half-dozen shots, we will assess the plasma quality (specifically
molybdenum content, radiated power, H-factor). If the quality is judged
unsatisfactory (by Earl), then we will switch to MP #264. (Granetz will
become session leader as well as physop.) For the disruption run, we will
drop back to 0.8 MA, ohmic, and use the lithium pellet injector to disrupt
the plasma at t=0.6 s. RF can be used later in the day, if the RF group
wants to stick around.

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

Overnight ECDC in D2 was done, stopping 2 hours prior to the run

Hybrid coldstart done; no errors found

Loaded 1000615001 and set density to nl_04=1.1e20 m-2. Load CLEARIN
from shot 1000613006, in order to get the new offset. Load segments
3 and 4 with a good shot from the neutral point run (1000526022),
updating CLEARIN to use the new offset. Add a -7 kA TF waggle from
t=0.90-1.02 s for GPC pedestal profiles.

Note: the planned TF test is not required after all, but the "back
porch" on the TF is requested, and is indeed programmed.

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

Shot 01 -- Plasma. Good shot. 1 MA, 5.3 T. Neutron rate surpasses 4e13/s.
Prf=2.2-2.8 MW. Wp=160 kJ. Good gaps (11 mm outer, 15 mm
inner). Constant EDA H-mode. H_factor=1.7-1.8.

Next shot: repeat, with RF flat, instead of slightly ramped. Add
3 ms to pre-fill pulse length.

Shot 02 -- Plasma. Good shot. Very similar to the previous shot, with a very
good, flat RF pulse. Prf=2.8 MW for 0.7 s. Neutron rate droops
slightly by the end of the RF pulse. Zeff=2.2.

Next shot: raise Ip to 1.1 MA (from 1.0) and raise target density
to nl_04=1.2e20 m-2 (from 1.1).

Shot 03 -- Plasma. Good shot. 1.1 MA, 5.3 T. Prf=2.7 MW. Neutron rate is
slightly lower, and has a droop.

Next shot: raise Btor to 5.4 T (from 5.3), and drop the density
back to nl_04=1.1e20 m-2.

Shot 04 -- Plasma. Good shot. 1.1 MA, 5.4 T. Wp reaches 170 kJ. Prf=2.78 MW.
Nice steady EDA H-mode.

Next shot: reduce density to nl_04=1.0e20 m-2.

Shot 05 -- Plasma. Good shot. 1.1 MA, 5.4 T. Wp is lower...less than 150 kJ.
Lowering the density didn't seem to be a good thing.

Next shot: raise density back to nl_04=1.1e20 m-2, raise ZCUR by
1 cm from t=0.7 s to increase kappa, and reverse the polarity of
the TF waggle.

Shot 06 -- Plasma. Good shot. There was an injection in the middle of the
RF pulse, which reduced the plasma performance noticeably.

Next shot: repeat, no PCS changes. Still no argon.

Shot 07 -- Plasma. Good shot. There was a big injection from the top corner
of the E-port antenna at t=1.35 s. The shot was pretty good up
until the injection.

Next shot: reload shot 01 (segment 2), except set the TF to 5.4 T
and keep the TF waggle polarity the same as shot 06.

Shot 08 -- Plasma. Good shot. H/D has crept up a bit to 4%. This shot was
not as high a Wp as shot 01.

Next shot: no PCS changes. RF programming will be a little
different.

Shot 09 -- Plasma. Good shot. Wp=174 kJ. Prf=3.2 MW. Nice steady EDA H-mode.

Next shot: end RF pulse at t=1.3 s (to reduce antenna heatup).
Start Ip, Btor, and ne rampdown at t=1.35 s. Turn on argon, with
a 25 ms pulse.

Shot 10 -- Plasma. Good shot. I forgot to have the argon valve enabled.
Neutron rate reached 6e13/s. Prf was slightly higher than previous
shot.

Next shot: Argon valve IS enabled.

Shot 11 -- Plasma. Good shot. Some bad injections occurred.

Next shot: raise density to nl_04=1.3e20 m-2.

Shot 12 -- Plasma. Good shot. No injections. Density during H-mode was
not significantly higher than previous shot. Argon signal is
very low. Wp peaks at 180 kJ. Prf=3.0 MW.

Next shot: increase argon pulse to 35 ms (from 25 ms). More RF
tuning.

Shot 13 -- Plasma. Good shot. Prf>3.5 MW. Rn>6e13/s. Wp peaks at 192 kJ.
RF pulse duration was not as long as previous shots. There was
a problem with an RF power supply at t=1.1 s.

Next shot: increase argon pulse to 50 ms (from 35 ms)

There was a 30-minute delay between shots 13 and 14 while the RF was checked
out.

Shot 14 -- Plasma. Good shot. E-port transmitter faulted early. Argon
signal levels are acceptable.

Next shot: no PCS changes. Repeat for RF

Shot 15 -- Plasma. Good shot. E-port transmitter faulted early again.

Next shot: no PCS changes. Repeat for RF

Shot 16 -- Plasma. Good shot. Prf=3.0 MW. Rn=3-3.5e13/s. H/D=3.0 %
Wp=165 kJ.

Next shot: ramp Ip down a little faster.

Shot 17 -- Plasma. Good shot. Similar to preceding shot.

Next shot: repeat

Shot 18 -- Plasma. Good shot. Similar to preceding two shots. John Rice
is using this series of similar shots to get a Ti profile.

Next shot: repeat

Shot 19 -- Plasma. Good shot. Similar to preceding three shots. John Rice
is getting a good Ti profile from this series. With this shot,
he finished.

Next shot: raise Ip to 1.2 MA and raise density to nl_04=1.5e20 m-2.

Shot 20 -- Plasma. Good shot. 1.2 MA, 5.4 T, nl_04=1.5e20 m-2 target. E-port
antenna faulted. There was an injection at t=0.89 s. Wp peaked
at 180 kJ.

Next shot: reduce argon pulse to 40 ms (from 50 ms).

Shot 21 -- Plasma. Good shot. Ip=1.2 MA. This shot started out much better
than the previous one (Rn=5-6e13/s), but E-port antenna faulted
again. Wp peaked at 203 kJ.

Next shot: raise density to nl_04=3.0e20 m-2 during the H-mode
portion of the discharge.

Shot 22 -- Plasma. Good shot. Ip=1.2 MA, nl_04 reaches 2.6e20 m-2 during the
H-mode. There were some injections. Wp peaks at 208 kJ. Prf=3.0 MW.

End of run

Session Leader Comments
Jun 16 2000 10:04:28:450AMEarl MarmarToday's run will start with an attempt to optimize "high" performance.

Aim for I_p > 1 MA, P_rf ~ 3 MW from D and E

knobs: B_T, n_e, I_p, kappa
Jun 16 2000 10:06:59:607AM1000616001Earl Marmarplasma

very nice 1 MA EDA

RF starts at about 2 MW and then gently ramps up to 2.8 MW

taking absorbed fraction of RF = 0.8, get H-factor > 1.7

neutron rate > 5e13 /s

stored energy 160 kJ
Jun 16 2000 10:08:28:403AM1000616002Earl MarmarRepeat with RF up to full power earlier

plasma

another nice EDA

stored energy and neutron rate both drooping slightly during the RF pulse

2.7 MW RF, very steady
Jun 16 2000 10:09:49:780AM1000616003Earl Marmarplasma

1.1 MA

nl_04 to 1.2e20 (from 1.1)

same stored energy (162 kJ), but lower neutron rate, higher radiated power
Jun 16 2000 10:22:28:967AM1000616004Earl Marmarplasma

1.1 MA, B_T up to 5.4 T (from 5.3)

nl_04 back to 1.1e20

nice EDA

170 kJ stored energy

Radiated power was dropping slightly during the RF
Jun 16 2000 10:53:19:590AM1000616005Earl Marmarnl_04 to 1.0e20

plasma

decent EDA

confinement drooping and then goes back up
Jun 16 2000 11:19:19:593AM1000616006Earl Marmarback to nl_04=1.1e20

move plasma up 1 cm to increase kappa

plasma

not as nice; significant injection at 1.1 s
Jun 16 2000 11:21:33:357AM1000616007Earl Marmarrepeat with better RF tune

plasma

pretty good EDA until 1.33 s, when upper left corner of E-port injects generously into the plasma
Jun 16 2000 02:10:04:420PM1000616012Earl MarmarRaise nl_04 to 1.3 e20

plasma

lower radiated power

RF power a bit lower, slightly off tune

175 kJ
Jun 16 2000 02:08:24:123PM1000616013Earl MarmarRF better tune

plasma

very nice EDA to 1.1, then one transmitter tripped

190kJ stored energy

Jun 16 2000 02:23:47:153PM1000616014Earl Marmarreduce RF power slightly (on D)

plasma

E port transmitter tripped at 0.9 seconds
Jun 16 2000 02:39:23:390PM1000616015Earl Marmarretry

plasma

E port still tripped, even earlier
Jun 16 2000 05:28:01:810PM1000616016Earl MarmarBack off on E-Port power

plasma

good steady EDA; RF stayed on

166 kJ peak
Jun 16 2000 05:35:40:607PM1000616017Earl Marmarplasma

steady EDA

168 kJ
Jun 16 2000 05:35:02:433PM1000616018Earl Marmarplasma

nice steady EDA

166 kJ
Jun 16 2000 05:34:16:827PM1000616019Earl Marmarlast of 3 shots for Hirex profile

plasma

slight dip in stored energy after 1 sec
Jun 16 2000 05:33:17:780PM1000616020Earl Marmar1.2 MA

plasma

RF a bit ratty
Jun 16 2000 05:32:32:263PM1000616021Earl Marmarplasma

started out looking good, until 0.97, when one transmitter tripped

radiated power topped out at 2 MW
Jun 16 2000 05:30:16:763PM1000616022Earl Marmarpuff during the H-mode

plasma

good EDA

RF went through

Confinement started good, then degraded, then started to recover

radiated power decreasing after initial peak

Brian reports high midplane pressure during the H-mode


Physics Operator Comments
Jun 15 2000 05:46:53:043PMRobert GranetzEngineering setup for Friday, 16 June 2000:

Overnight ECDC in D2, stopping 1-2 hours prior to the run.

Run begins at 9:00 and ends at 17:00.

Power system setup as on 1000613006 (from Tuesday morning), including
fizzle delay settings

Gas setup - fill B-top with 6 psi of D2 Hybrid enabled
fill B-side lower with 1 psi of Ar Hybrid DISABLED
leave B-side upper as is Hybrid DISABLED
fill C-side with 30 psi of D2 Hybrid enabled
leave J-bottom as is Hybrid DISABLED

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

First shot will be a 50 kA TF-only test under PLC control.
Jun 15 2000 05:47:33:623PMRobert GranetzRun plan (two different MP's):

MP #248 -- High performance; Session leader: E. Marmar
MP #264 -- Neutral point disruption exp'ts (con't); Session leader: R. Granetz

PO: R. Granetz

The run will begin with MP #248. We will load from 1000615001 (1 MA, 5.3 T,
outer gap=12 mm), but set the density at nl_04=1.1e20 m-2 and load
CLEARIN from 1000613006 (which contains the new offset). RF (from D and E)
will turn on from t=0.8 to 1.5 s, at the highest power possible. We may
increase Ip to 1.1 MA after the first shot. Segments 3 and 4 have been
loaded with a good shot from the neutral point run (1000526022), with CLEARIN
loaded from 1000613006 to get the new offset. We will switch to these segments
for the disruption MP.

After a half-dozen shots, we will assess the plasma quality (specifically
molybdenum content, radiated power, H-factor). If the quality is judged
unsatisfactory (by Earl), then we will switch to MP #264. (Granetz will
become session leader as well as physop.) For the disruption run, we will
drop back to 0.8 MA, ohmic, and use the lithium pellet injector to disrupt
the plasma at t=0.6 s. RF can be used later in the day, if the RF group
wants to stick around.
Jun 16 2000 08:54:02:950AMRobert Granetz Overnight ECDC in D2 was done, stopping 2 hours prior to the run

Hybrid coldstart done; no errors found

Loaded 1000615001 and set density to nl_04=1.1e20 m-2. Load CLEARIN
from shot 1000613006, in order to get the new offset. Load segments
3 and 4 with a good shot from the neutral point run (1000526022),
updating CLEARIN to use the new offset. Add a -7 kA TF waggle from
t=0.90-1.02 s for GPC pedestal profiles.

Note: the planned TF test is not required after all, but the "back
porch" on the TF is requested, and is indeed programmed.
Jun 16 2000 09:45:29:750AM1000616001Robert GranetzShot 01 -- Plasma. Good shot. 1 MA, 5.3 T. Neutron rate surpasses 4e13/s. Prf=2.2-2.8 MW.
Wp=160 kJ. Good gaps (11 mm outer, 15 mm inner). Constant EDA
H-mode. H_factor=1.7-1.8.

Next shot: repeat, with RF flat, instead of slightly ramped. Add
3 ms to pre-fill pulse length.
Jun 16 2000 09:52:00:327AM1000616002Robert GranetzShot 02 -- Plasma. Good shot. Very similar to the previous shot, with a very
good, flat RF pulse. Prf=2.8 MW for 0.7 s. Neutron rate droops
slightly by the end of the RF pulse. Zeff=2.2.

Next shot: raise Ip to 1.1 MA (from 1.0) and raise target density
to nl_04=1.2e20 m-2 (from 1.1).
Jun 16 2000 09:54:15:170AM1000616003Robert GranetzShot 03 -- Plasma. Good shot. 1.1 MA, 5.3 T. Prf=2.7 MW. Neutron rate is
slightly lower, and has a droop.

Next shot: raise Btor to 5.4 T (from 5.3), and drop the density
back to nl_04=1.1e20 m-2.
Jun 16 2000 10:21:46:530AM1000616004Robert GranetzShot 04 -- Plasma. Good shot. 1.1 MA, 5.4 T. Wp reaches 170 kJ. Prf=2.78 MW.
Nice steady EDA H-mode.

Next shot: reduce density to nl_04=1.0e20 m-2.
Jun 16 2000 10:43:40:013AM1000616005Robert GranetzShot 05 -- Plasma. Good shot. 1.1 MA, 5.4 T. Wp is lower...less than 150 kJ.
Lowering the density didn't seem to be a good thing.

Next shot: raise density back to nl_04=1.1e20 m-2, raise ZCUR by
1 cm from t=0.7 s to increase kappa, and reverse the polarity of
the TF waggle.
Jun 16 2000 11:01:33:297AM1000616006Robert GranetzShot 06 -- Plasma. Good shot. There was an injection in the middle of the
RF pulse, which reduced the plasma performance noticeably.

Next shot: repeat, no PCS changes. Still no argon.
Jun 16 2000 11:44:20:327AM1000616008Robert GranetzShot 08 -- Plasma. Good shot. H/D has crept up a bit to 4%. This shot was
not as high a Wp as shot 01.

Next shot: no PCS changes. RF programming will be a little
different.
Jun 16 2000 12:12:10:060PM1000616009Robert GranetzShot 09 -- Plasma. Good shot. Wp=174 kJ. Prf=3.2 MW. Nice steady EDA H-mode.

Next shot: end RF pulse at t=1.3 s (to reduce antenna heatup).
Start Ip, Btor, and ne rampdown at t=1.35 s. Turn on argon, with
a 25 ms pulse.
Jun 16 2000 12:37:34:840PM1000616010Robert GranetzShot 10 -- Plasma. Good shot. I forgot to have the argon valve enabled.
Neutron rate reached 6e13/s. Prf was slightly higher than previous
shot.

Next shot: Argon valve IS enabled.
Jun 16 2000 12:51:11:000PM1000616011Robert GranetzShot 11 -- Plasma. Good shot. Some bad injections occurred.

Next shot: raise density to nl_04=1.3e20 m-2.
Jun 16 2000 01:10:00:403PM1000616012Robert GranetzShot 12 -- Plasma. Good shot. No injections. Density during H-mode was
not significantly higher than previous shot. Argon signal is
very low. Wp peaks at 180 kJ. Prf=3.0 MW.

Next shot: increase argon pulse to 35 ms (from 25 ms). More RF
tuning.
Jun 16 2000 01:31:54:327PM1000616013Robert GranetzShot 13 -- Plasma. Good shot. Prf>3.5 MW. Rn>6e13/s. Wp peaks at 192 kJ.
RF pulse duration was not as long as previous shots. There was
a problem with an RF power supply at t=1.1 s.

Next shot: increase argon pulse to 50 ms (from 35 ms)
Jun 16 2000 02:07:31:623PM1000616013Robert GranetzThere was a 30-minute delay between shots 13 and 14 while the RF was checked
out.
Jun 16 2000 02:16:18:047PM1000616014Robert GranetzShot 14 -- Plasma. Good shot. E-port transmitter faulted early. Argon
signal levels are acceptable.

Next shot: no PCS changes. Repeat for RF
Jun 16 2000 02:53:54:467PM1000616015Robert GranetzShot 15 -- Plasma. Good shot. E-port transmitter faulted early again.

Next shot: no PCS changes. Repeat for RF
Jun 16 2000 02:57:25:873PM1000616016Robert GranetzShot 16 -- Plasma. Good shot. Prf=3.0 MW. Rn=3-3.5e13/s. H/D=3.0 %
Wp=165 kJ.

Next shot: ramp Ip down a little faster.
Jun 16 2000 03:23:33:763PM1000616017Robert GranetzShot 17 -- Plasma. Good shot. Similar to preceding shot.

Next shot: repeat
Jun 16 2000 03:52:01:547PM1000616018Robert GranetzShot 18 -- Plasma. Good shot. Similar to preceding two shots. John Rice
is using this series of similar shots to get a Ti profile.

Next shot: repeat
Jun 16 2000 04:01:43:530PM1000616019Robert GranetzShot 19 -- Plasma. Good shot. Similar to preceding three shots. John Rice
is getting a good Ti profile from this series. With this shot,
he finished.

Next shot: raise Ip to 1.2 MA and raise density to nl_04=1.5e20 m-2.
Jun 16 2000 04:26:12:670PM1000616020Robert GranetzShot 20 -- Plasma. Good shot. 1.2 MA, 5.4 T, nl_04=1.5e20 m-2 target. E-port
antenna faulted. There was an injection at t=0.89 s. Wp peaked
at 180 kJ.

Next shot: reduce argon pulse to 40 ms (from 50 ms).
Jun 16 2000 04:48:42:780PM1000616021Robert GranetzShot 21 -- Plasma. Good shot. Ip=1.2 MA. This shot started out much better
than the previous one (Rn=5-6e13/s), but E-port antenna faulted
again. Wp peaked at 203 kJ.

Next shot: raise density to nl_04=3.0e20 m-2 during the H-mode
portion of the discharge.
Jun 16 2000 05:15:04:343PM1000616022Robert GranetzShot 22 -- Plasma. Good shot. Ip=1.2 MA, nl_04 reaches 2.6e20 m-2 during the
H-mode. There were some injections. Wp peaks at 208 kJ. Prf=3.0 MW.

End of run

Engineering Operator Comments
ShotTimeTypeStatusComment
109:03:42:687AMPlasmaOk
209:24:52:717AMPlasmaOk
309:45:03:403AMPlasmaOk
410:06:03:717AMPlasmaOk
510:26:25:623AMPlasmaOk
610:47:41:140AMPlasmaOk
711:09:53:653AMPlasmaOk
811:30:49:000AMPlasmaOk
911:52:06:827AMPlasmaOk
1012:13:19:717PMPlasmaOk
1112:36:44:857PMPlasmaOk
1212:55:59:340PMPlasmaOk
1301:18:21:170PMPlasmaOk
1402:08:11:233PMPlasmaOk
1502:25:36:327PMPlasmaOk
1602:45:53:107PMPlasmaOk
1703:06:50:153PMPlasmaOk
1803:26:57:890PMPlasmaOk
1903:47:36:857PMPlasmaOk
2004:13:32:217PMPlasmaOk
2104:33:24:357PMPlasmaOk
2204:55:25:497PMPlasmaOk