C-Mod/PSFC MFE DoE Quarterly Review August 10, 2015

Transcription

1 C-Mod/PSFC MFE DoE Quarterly Review August 10, 2015 Status of Agreements and Subcontracts (Marmar) C-Mod Facility (Irby) Priority Research Topics, Runtime (Granetz) MDSplus (Greenwald) International Collaborations (Bonoli/Wukitch) Research supported by U.S. Department of Energy, Fusion Energy Sciences

2 Status of Agreements and Subcontracts Final C-Mod Cooperative Agreement 1 year extension (for 9/1/15-8/31/16) submitted (7/24), now in review at FES NSTX-U subcontract (with PPPL) Ongoing Currently supporting 1 MIT graduate student Analysis of existing NSTX data Planning for NSTX-U experiments Ramp-up other activities after completion of FY16 C-Mod Campaign DIII-D subcontract (with GA) Paperwork sent to MIT OSP (7/17), to GA a week later Planning for 9/1/15 start Planning to hire 2 post-docs (request submitted to MIT VP for Research) New Five Year Cooperative Agreement for collaborations reviewed, now at DOE Chicago

3 Facility Status 08/10/2015

4 Outline Machine Status Engineering Systems Alternator ICRF Lower Hybrid Diagnostics Short Term Schedule

5 Machine Status Alternator to full speed on 04/08/15 Pump-down on 04/17/15 C-Mod began plasma operations on 04/30/15 after one day of power system testing 1155 plasma discharges thus far Startup reliability ~86% 7.2 out of 12 weeks of research completed

6 Engineering Systems

7 Alternator Alternator has been operational with high reliability since plasma operations began Insurance covered all repair costs MIT Alternator

8 ICRF Systems Four new enhanced anode FPA tubes are in-house, but not yet needed (prototype still in operation) D- and E-Port antennas have been brought back up to full power operation (1.5 MW each into plasma) The Field Aligned J-Port antenna been limited to 1.5 to 2 MW into plasma (rather than 3.0 MW) An up-to-argon was performed to investigate in early July Cabling for antenna thermocouples had become loose/displaced and was in close proximity to the rf feedthroughs --- we were able to pull back and secure the cabling The braid on the cables had become frayed and steel dust was found in the antenna box A manned up-to-air will be required to fully fix the problem However, progress has been made in conditioning the antenna Investigating fault in FMIT#2 high voltage power supply Occurred during intense thunder storm on Tuesday, 8/4 Suspect current surge (lightning strike) FA J-Port Antenna

9 Lower Hybrid Systems LH Operation Launcher was refurbished during upto-air and calibrations were checked kw reliably coupled to plasma during this campaign Experiments conducted to study fast electron content in the SOL LH systems, DNB, and MSE will continue to support the 2015 JRT in the 4 th quarter Figure of betat^2*b0^4 as a function of sqrt(epsilon)*betap from C-Mod discharges with LHCD. Beta is expressed in %. Color indicates plasma current in Amps.

10 Diagnostic Systems

11 AIMS RFQ Cavity Ion source and lens RFQ Following Clean-up After the refurbishment of components described during our last quarterly, CMM, laser, and phosphor screen and Faraday cup techniques have been used to align the AIMS components to within a few mils The system is now in the test cell being brought into operation

12 S 3 : A new probe head to study parallel wavenumber of lower hybrid waves is near completion. Six magnetic probes have been fabricated in house (collaboration with the University of Tokyo) New Mo tiles and a fixture that holds the probes have been fabricated in house. We are currently installing the magnetic probes and Langmuir probes in this probe head. The probe head will be mounted on the existing Surface Science Station [R. Ochoukov, MIT PhD Thesis 2013]. Magnetic Probes 3D-Printed 625 Inconel An intermediate frequency system that down-converts from 4.6 GHz to 25 MHZ has been tested. A new fast speed digitizer at 100 MHz is now synchronized with the C-Mod shot cycle. The digitizer is triggered up to 90 times for every 10 msec in a burst mode. In each trigger event, the digitizer samples 4096 data points ( microseconds).

13 3D-Printed Camera Mounts 3D-Printing can be used to very rapidly produce mounts, flanges, and other small components needed for our diagnostics Printing in both metal and plastic is possible Mounts for cameras interfacing to Raspberry Pi computers are shown

14 New Spectrometers 2 new high-throughput scannable spectrometers brought online (HTSpec 1, 2) Designed and built in house as graduate student project Expand visible spectroscopy from 16 to 66 sightlines F/#=2, ~4x the throughput of existing survey spectrometer (CHROMEX) 0.5nm resolution, 60nm span Fiber splitters being developed to enable measurements in multiple wavelength region on same sightline Will be used to study divertor physics: Monitor the detachment front Impurity radiation for dissipative divertors Line ratios for temperature, density Stark broadening for density Support new multi-spectral imaging system under development Assembled and aligned, expect first plasma light very soon (interfacing with tree underway) HTSpec 1 and 2

15 MSE Multi-spectral Line Polarization MSE (MSE-MSLP) now fully-operational Designed as an MIT graduate student project with PPPL 10 sightline system replaces TFTR era detectors Measures polarization in 4 wavelengths simultaneously on same sightline Allows better background subtraction using wavelength-interpolation instead of timeinterpolation Increases signal by measuring multiple Stark lines Monitors the polarization calibration Expands MSE operation space to higher densities and powers Fully remote controlled enabling future collaborations Technique adopted for ITER polarization MSE MSE-MSLP system in diagnostic hall

16 Advanced Divertor Diagnostics Divertor surface thermocouples are being integrated into the digital plasma control system for real-time control of divertor heat flux An analog circuit 'solves' 1-D heat transport problem with surface temperature inputs and then outputs real-time signals of surface heat flux Feedback control of nitrogen seeding based on divertor surface heat fluxes demonstrated for the first time in a tokamak (MP784) Signals are robust, immune to RF pickup (3 MW ICRF thus far) Further refinements to instrumentation are being made to handle variations in divertor potentials Planning to submit request for APS post-deadline invited talk New flush-mounted 'rail' Langmuir probes are functioning well These large-area probes draw significant saturation currents New 3.3kW audio power supply has been installed to drive the array Rail geometry works: I-V characteristics are easy to interpret, plasma densities and temperatures match conventional button probes Working on physics interpretation when magnetic field nearly tangent to probe (projected area goes to zero) New Rail Probe Arrays

17 Advanced Divertor Diagnostics Mirror Langmuir probe system on the scanning probe continues to collect data on the boundary plasma in unprecedented detail (used for many MPs) New servomotor-controlled scanning probe work is progressing Hardware assembly is nearly complete and electronic control system is being fabricated. This system will replace the present A-port scanning drive that is used for the scanning Mirror Langmuir Probe system and will greatly increase its effectiveness for experiments. Progress is being made on implementing a Mirror Langmuir probe system for the J-divertor Langmuir probes Nearly all components have been purchased Printed circuit boards for the analog computer of the MLP system will be sent out for loading soon Wall-Actuated Scanning Probes have provided essential data on the high-field side SOL for a number of MPs One very important experiment focused on the scaling of the HFS scrape-off layer width (MP782) Three electrodes were damaged during recent experiments - one on WASP-A and two on WASP-K. An up-to-air manned access will be needed to repair them.

18 Short Term Schedule Planning for 12 weeks of research operation in FY2015 Approximately 7.2 weeks completed thus far

19 EOT

20 C-Mod FY2015 run campaign presented by R. Granetz Alcator C-Mod quarterly review 2015/08/10

21 C-Mod FY2015 run campaign Budgeted for 12 research run weeks 7.2 run weeks have been completed to date 4.8 run weeks will be completed in remaining 7.5 calendar weeks of FY2015 Next year s (FY2016) guidance budget provides for a maximum of 5 weeks of operation, and then C-Mod is scheduled to cease operation, so there is intense pressure on run time 2/3

22 C-Mod FY2015 run campaign The FY2015 campaign is split into two main segments Forward field: Power handling in SOL, width scaling, N 2 feedback Lower hybrid (2015 JRT is on off-axis current drive); high-quality MSE; density limit; LH effects in SOL Turbulence (ETG, high-k); LOC/SOC regimes; QCM (MLP, shoelace antenna) Impurity screening (inboard/outboard asymmetries) ITER requests (disruption mitigation, He H-modes w/high-z wall) Reversed field: High performance I-mode, including 8 tesla ICRF mode conversion; other RF scenarios Runaway electron synchrotron studies; mitigation 3/3

23 FY15 Campaign Status and Plans Topical Area Target Allocation Run Days by 8/10 Boundary Pedestal Core Transport ITER* RF Disruptions Diagnostic Dev. 1.6 * ITER allocation doesn t include ~ 20.5 run days allocated in other topical areas for ITER support and ITPA experiments C-Mod Quarterly 8/10/15 Run Planning 4

24 MDSplus DOE Quarterly Review 8/10/15 MIT-PSFC

25 MDSplus Data System Two new core MDSplus developers, 1 fulltime at IGI in Padua and % at PPPL Software Quality Project Source management migrated from CVS to GIT New build/release system, new build system for windows version Complete rewrite of non-conforming modules (command parser) Automated unit testing Documentation Doxygen documentation generator built into configuration and build process New tutorials, examples provided New Tools Webscope web based data display piscope python based display and analysis platform jscope java based display, supports data streaming, decimation C-Mod quarterly 8/10/15 MDSplus 2

26 MDSplus Major Collaboration Activities W7X W7X will use MDSplus for many diagnostics for (at least) OP1.1 and OP1.2 o Active discussion of any new requirements for long-pulse operation J. Stillerman traveled to Greifswald to assist with MDSplus configuration and architecture ahead of OP1.1 All data from W7X, including data acquired by core CODAC system will be available through MDSplus Diagnostics from outside collaborators to be delivered with native MDSplus KSTAR One week visit to Daejon in March to address local MDSplus issues Discussed possible big data extensions to MDSplus IAEA Technical Meeting & User group meeting in April, Ahmedabad India Many MDSplus related presentations from core developers and users Annual developers meeting will be held later this month C-Mod quarterly 8/10/15 MDSplus 3

27 International Collaboration: Development of long-pulse RF actuators and Operational Techniques for High Z PFC S. J. Wukitch On behalf of the MIT Team: DoE Teleconference August 10, 2015

28 Higher Efficiency Heating was Observed for EAST ICRF YijunLinvisitedEASTinJulytoimproveICRF coupling and heating. EAST has a goal to reliably couple 70% of source power into plasma for >100 s. Increasing coupling efficiency is critical. Maximum coupled power from two antennas is 2.8 MW into L-mode plasma. Recent experiments were performed with nonstandard antenna phase to generate low k to increase antenna coupling efficiency (motivated by ICRF-TORIC simulations performed by E. Edlund): For I antenna, phase was [0,30,60,90 ]: k ~2.4 m -1 (compared to 14.4 m -1 ). About 3 time higher heating efficiency is observed. Maximum voltage decreased ~25% which is ~55% increase in loading. Potential to increase coupled power by 55%. I antenna Implication is that to achieve 70% coupled power, the antenna needs to be modified as well to improve coupling.

29 Long Pulse Disruption Free Control - EAST R. Granetz visited EAST in July 19-31, 2015: At beginning of 2015 campaign MDSplus model tree containing nodes and data to support filament reconstruction program was inadvertently corrupted: Worked with MDS expert at EAST (Yang Fei) to resurrect everything so that these program would work again. Ran batch jobs for about 3 days to process every disruption in 2015 and write the results to the trees. Worked with graduate student (GS) from China on disruption databases on EAST and Alcator C-Mod. Student is working on a neural network approach for a real-time disruption warning algorithm. Student will be coming to MIT in August, 2015 for a 5-week visit to continue working on this topic. Analyzed the disruption on EAST in USN that ended the campaign on July 28, 2015: Determined the plasma did not hit the lower divertor during this discharge.

30 Long Pulse Disruption Free Control - EAST R. Granetz visit - continued Worked closely with another Chinese GS and his advisor to analyze enhanced halo current disruption data: Found for downward-going disruptions that end up contacting the lower divertor dome, most of the halo current goes directly from one side of the dome to the other, without passing through any of the original instrumentation on the dome supports. Found that disruptions on which the LH power stays on during the current quench have a lot more halo current than disruptions without the LH. Worked with same GS to completely rewrite a paper that has now been submitted to Rev. Sci. Instrum. on the upgraded, extensive set of halo current diagnostics. Detailed discussions with Jiangang Li and Damao Yao about their possible interest in a hot divertor (600 C) for EAST: Especially challenging in a long-pulse device such as EAST because the hot divertor will have to be cooled.

31 International Collaboration on Control and Extension of ITER and Advanced Scenarios to Long Pulse in EAST and KSTAR P. T. Bonoli On behalf of the MIT Team: S. G. Baek, R. S. Granetz, E. Edlund, A. E. Hubbard, Y. Lin, R. R. Parker, M. Porkolab, J. E. Rice, S. Shiraiwa, J. Stillerman, G. M. Wallace, and J. C. Wright DoE Teleconference August 10, 2015

32 Task 1: Extension of the I-Mode scenario to EAST A. Hubbard visited ASIPP on July 19-25, 2015 to conduct initial experiments for the proposal Development and study of I-mode on EAST : Contacts at EAST: X. Gao, T. Zhang, Z. X. Liu, G. Q. Li, Y. Yang, D.F. Kong, X. Han, and C. Huang. Also part of an ITPA Joint Experiment PEP-31. Hardware commissioning issues have compressed the nominally planned physics portion of the campaign to only a week or two. Got five discharges for experiment but not in USN configuration, which would place the B B in the unfavorable direction (which is needed for these experiments). Used these discharges to run LSN threshold comparison shots, at the same parameters that were intended for the USN.

33 Task 1: Extension of the I-Mode scenario to EAST Visit by A. Hubbard to ASIPP on July 19-25, continued Also able to assess the diagnostic data under conditions comparable to what will be needed for I-Mode. Revealed some unexpected degradation during the discharge due to MHD a result of the choice of heating mix and waveform. EAST did run a number of USN discharges during the week of July 27-31, 2015: Most of these discharges transitioned to H-Mode. Canbing Huang is analyzing P(L-H) threshold data. Experiments will not give accurate P(L-H) but may serve to bracket the power range, which seems relatively low. Will request further discharges in the next EAST campaign and consider visiting again for such an experiment. On-site visit was useful in terms of gaining experience with EAST data access and tools.

34 Task 3. Diagnostic and Actuator Development for Scenario Extension - EAST Worked with B. Ding on publication for Nuclear Fusion (accepted for publication in 2015): Investigations of LHW-plasma coupling and current drive at high density related to H-mode experiments in EAST. Co-authored with P. T. Bonoli, S. G. Baek, and R. Parker: Did extensive rewriting of paper sections for review process. High density experiments with 2.45 GHz LHCD power in EAST were further analyzed by means of simulation: Showed that Parametric Instability (PI), Collisional Absorption (CA), and density fluctuations in the edge region could be responsible for the low CD efficiency at high density.

35 Task 3. Diagnostic and Actuator Development for Scenario Extension - EAST Simulation studies of LHCD in EAST (S. Shiraiwa, P. T. Bonoli, J. C. Wright; Boijang Ding, Miaohui Li, Cheng Yang): Continued studies using GENRAY / CQL3D to show that peaked hard x-ray and current density profiles in EAST experiments can be reproduced in simulations by slightly broadening the incident LH power spectrum (5% of power put in a lobe at n // = 2.75). Submitted paper for conference proceedings which included this work: S. Shiraiwa et al, Invited Talk at the 21st Topical Conference on Radio-frequency Power in Plasmas, April 2015, Lake ArrowHead, CA.

36 Task 3. Diagnostic and Actuator Development for Scenario Extension - EAST Comparison of measured and simulated HXR emission profiles and current profile prediction: EAST discharge #48888 at 5.5s Experiment (blue) Simulation without spectral spreading (red) Simulation with spectral spreading (green) Agreement between measured and simulated HXR profiles is improved with spectral broadening. S. Shiraiwa, RF Topical Conference 2015

37 Task 3. Diagnostic and Actuator Development for Scenario Extension - KSTAR Working with Y. S. Bae on LHCD simulations for KSTAR: (S. Shiraiwa, P. T. Bonoli, J. C. Wright, R. Parker, and G. Wallace): Draft of paper has been prepared for Plasma Physics and Controlled Fusion: Simulation Study of Off-Midplane LHCD in KSTAR Surveyed LH wave launch parameters and operating conditions in KSTAR, including compatibility issues with the existing in-vessel components: LH wave launch from the top position near the upper X-point provides adequate wave accessibility and reduces parasitic edge losses for the KSTAR high performance H-mode operation scenario using 5 GHz LHRF power: Requires new hardware and removal of the upper divertor plates and in-vessel cryo-pump for installation.

38 Task 3. Diagnostic and Actuator Development for Scenario Extension - KSTAR Simulations performed with GENRAY / CQL3D: n e (0) = m-3, T e (0) = 5 kev, B t = 2 T f 0 = 5 GHz, n // = CD = (10 20 A/W/m 2 ) Y.-S. Bae et al, prepared for PPCF