Measurement of Electron Density Profile and Fluctuations on HSX C. Deng, D.L. Brower, W.X. Ding Electrical Engineering Department University of California,

Slides:

Advertisements

Similar presentations

Ion Heating and Velocity Fluctuation Measurements in MST Sanjay Gangadhara, Darren Craig, David Ennis, Gennady Fiskel and the MST team University of Wisconsin-Madison.

Advertisements

FAR-IR OPTICS DESIGN AND VERIFICATION EXPERIMENTAL SYSTEM AND RESULTS Final Meeting “Far-IR Optics Design and Verification”, Phase 2 27 November 2002,

9th TTF Spain September 11, 2002 B. J. Peterson, NIFS, Japan page 1 Radiative Collapse and Density Limit in the Large Helical Device.

FEC 2004 Measurements and Modeling of Plasma Flow Damping in the HSX Stellarator S.P. Gerhardt, A.F. Almagri, D.T. Anderson, F.S.B. Anderson, D. Brower,

DPP 2006 Reduction of Particle and Heat Transport in HSX with Quasisymmetry J.M. Canik, D.T.Anderson, F.S.B. Anderson, K.M. Likin, J.N. Talmadge, K. Zhai.

Measurement of magnetic island width by using multi-channel ECE radiometer on HT-7 tokamak Han Xiang( 韩翔 ), Ling Bili( 凌必利 ), Gao Xiang( 高翔 ), Liu Yong(

49th Annual Meeting of the Division of Plasma Physics, November , 2007, Orlando, Florida Ion Temperature Measurements and Impurity Radiation in.

N=4,m=0 n=4,m=1 n=8,m=0 The HSX Experimental Program Program F. Simon B. Anderson, D.T. Anderson, A.R. Briesemeister, C. Clark, K.M.Likin, J. Lore, H.

Measurements with the KSTAR Beam Emission Spectroscopy diagnostic system Máté Lampert Wigner Research Centre for Physics Hungarian Academy of Sciences.

Nils P. Basse Plasma Science and Fusion Center Massachusetts Institute of Technology Cambridge, MA USA ABB seminar November 7th, 2005 Measurements.

Reflectometry on Alcator C-Mod: Status and future upgrades Outline: C-Mod reflectometry Physics examples Upgrades: 1.High frequency 2.Sideband 3.Data acquisition.

D.L. Brower, W.X. Ding, B.H. Deng Plasma Science and Technology Institute University of California, Los Angeles T.N. Carlstrom, M.A. Van Zeeland General.

Profile Measurement of HSX Plasma Using Thomson Scattering K. Zhai, F.S.B. Anderson, J. Canik, K. Likin, K. J. Willis, D.T. Anderson, HSX Plasma Laboratory,

A Singular Value Decomposition Method For Inverting Line Integrated Electron Density Measurements in Magnetically Confined Plasma Christopher Carey, The.

30 th EPS conference, St. Petersburg, Russia, July, 7-11, 2003 K.M.Likin On behalf of HSX Team University of Wisconsin-Madison, USA Comparison of Electron.

The toroidal current is consistent with numerical estimates of bootstrap current The measured magnetic diagnostic signals match predictions of V3FIT Comparisons.

12/03/2013, Praga 1 Plasma MHD Activity Observations via Magnetics Diagnostics: Magnetic island Analysis Magnetic island Analysis Frederik Ostyn (UGent)

Characterization of core and edge turbulence in L- and H-mode Alcator C-Mod plasmas Outline: Alcator C-Mod tokamak Fluctuation diagnostics Low to high.

Tunable, resonant heterodyne interferometer for neutral hydrogen measurements in tokamak plasmas * J.J. Moschella, R.C. Hazelton, M.D. Keitz, and C.C.

Fyzika tokamaků1: Úvod, opakování1 Tokamak Physics Jan Mlynář 8. Heating and current drive Neutral beam heating and current drive,... to be continued.

NSTX Boundary Density Fluctuation Measurement by FIReTIP System with USN/LSN Configurations K.C. Lee, C.W. Domier, M. Johnson, N.C. Luhmann, Jr. University.

Electron Density Distribution in HSX C. Deng, D.L. Brower Electrical Engineering Department University of California, Los Angeles J. Canik, S.P. Gerhardt,

Study of NSTX Electron Density and Magnetic Field Fluctuation using the FIReTIP System K.C. Lee, C.W. Domier, M. Johnson, N.C. Luhmann, Jr. University.

J. Boedo, UCSD Fast Probe Results and Plans By J. Boedo For the UCSD and NSTX Teams.

Measurements of plasma turbulence by laser scattering in the Wendelstein 7-AS stellarator Nils P. Basse 1,2, S. Zoletnik, M. Saffman, P. K. Michelsen and.

FEC 2006 Reduction of Neoclassical Transport and Observation of a Fast Electron Driven Instability with Quasisymmetry in HSX J.M. Canik 1, D.L. Brower.

47th Annual Meeting of the Division of Plasma Physics, October 24-28, 2005, Denver, Colorado ECE spectrum of HSX plasma at 0.5 T K.M.Likin, H.J.Lu, D.T.Anderson,

52 nd APS-DPP Annual Meeting, November, 8-12, 2010, Chicago, IL Plasma Pressure / BJ Contours Poloidal dimension Radial dimension Toroidal Angle (rad)

47th Annual Meeting of the Division of Plasma Physics, October 24-28, 2005, Denver, Colorado 1 Tesla Operation of the HSX Stellarator Simon Anderson, A.Almagri,

52nd Annual Meeting of the Division of Plasma Physics, November , 2010, Chicago, Illinois Non-symmetric components were intentionally added to the.

1) For equivalent ECRH power, off-axis heating results in lower stored energy and lower core temperature 2) Plasma flow is significantly reduced with off-axis.

Measurements of Magnetic Fluctuations in HSX S. Oh, A.F. Almagri, D.T. Anderson, C. Deng, C. Lechte, K.M. Likin, J.N. Talmadge, J. Schmitt HSX Plasma Laboratory,

Helically Symmetry Configuration Evidence for Alfvénic Fluctuations in Quasi-Helically Symmetric HSX Plasmas C. Deng and D.L. Brower, University of California,

51 st APS-DPP Annual Meeting, 2-6 November 2009, Atlanta GA Time BθBθ Φ≈ 1/6 FP Φ≈1/2 FP J Pfirsh-Schlüter Poloidal Index BθBθ.

APS, 44th Annual Meeting of the Division of Plasma Physics November 11-15, 2002; Orlando, Florida Hard X-ray Diagnostics in the HSX A. E. Abdou, A. F.

52nd Annual Meeting of the Division of Plasma Physics, November , 2010, Chicago, Illinois 5-pin Langmuir probe configured to measure floating potential.

53rd Annual Meeting of the Division of Plasma Physics, November , 2010, Salt Lake City, Utah 5-pin Langmuir probe configured to measure the Reynolds.

53rd Annual Meeting of the Division of Plasma Physics, November , 2011, Salt Lake City, Utah When the total flow will move approximately along the.

4. Neoclassical vs Anomalous Transport: Crucial Issue for Quasisymmetric Stellarators Overview of HSX Experimental Program J.N. Talmadge, A. Abdou, A.F.

5.4 Stored Energy Crashes  Diamagnetic loop shows the plasma energy crashes at low plasma density  ECE signals are in phase with the energy crashes 

1 ASIPP Sawtooth Stabilization by Barely Trapped Energetic Electrons Produced by ECRH Zhou Deng, Wang Shaojie, Zhang Cheng Institute of Plasma Physics,

= Boozer g= 2*1e -7 *48*14*5361 =.7205 =0 in net current free stellarator, but not a tokamak. QHS Mirror Predicted Separatrix Position Measurements and.

51st Annual Meeting of the Division of Plasma Physics, November 2 - 6, 2009, Atlanta, Georgia ∆I BS = 170 Amps J BS e-root J BS i-root Multiple ambipolar.

Plasma Turbulence in the HSX Stellarator Experiment and Probes C. Lechte, W. Guttenfelder, K. Likin, J.N. Talmadge, D.T. Anderson HSX Plasma Laboratory,

First Thomson Scattering Results on HSX K. Zhai, F.S.B. Anderson, and D.T. Anderson HSX Plasma Laboratory, U. of Wisconsin, Madison 1. Abstract 5. Summary.

Effects of Symmetry-Breaking on Plasma Formation and Stored Energy in HSX Presented by D.T. Anderson for the HSX Team University of Wisconsin-Madison 2001.

Electron Cyclotron Heating in the Helically Symmetric Experiment J.N. Talmadge, K.M. Likin, A. Abdou, A. Almagri, D.T. Anderson, F.S.B. Anderson, J. Canik,

18 th Int’l Stellarator/Heliotron Workshop, 29 Jan. – 3 Feb. 2012, Canberra – Murramarang Reserve, Australia Recent Results and New Directions of the HSX.

Hard X-rays from Superthermal Electrons in the HSX Stellarator Preliminary Examination for Ali E. Abdou Student at the Department of Engineering Physics.

= 2·10 18 m -3 T e (0) = 0.4 keV ECH and ECE on HSX Stellarator K.M.Likin, A.F.Almagri, D.T.Anderson, F.S.B.Anderson, C.Deng 1, C.W.Domier 2, R.W.Harvey.

54 th APS-DPP Annual Meeting, October 29 - November 2, 2012, Providence, RI Study of ICRH and Ion Confinement in the HSX Stellarator K. M. Likin, S. Murakami.

C. Deng and D.L. Brower University of California, Los Angeles J. Canik, D.T. Anderson, F.S.B. Anderson and the HSX Group University of Wisconsin-Madison.

Profiles of density fluctuations in frequency range of (20-110)kHz Core density fluctuations Parallel flow measured by CHERS Core Density Fluctuations.

Soft X-Ray Tomography in HSX V. Sakaguchi, A.F. Almagri, D.T. Anderson, F.S.B. Anderson, K. Likin & the HSX Team The HSX Plasma Laboratory University of.

54th Annual Meeting of the Division of Plasma Physics, October 29 – November 2, 2012, Providence, Rhode Island 5-pin Langmuir probe measures floating potential.

48th Annual Meeting of the Division of Plasma Physics, October 30 – November 3, 2006, Philadelphia, Pennsylvania Energetic-Electron-Driven Alfvénic Modes.

48th Annual Meeting of the Division of Plasma Physics, October 30 – November 3, 2006, Philadelphia, Pennsylvania HIBP Designs for Measurement of the Electric.

Neoclassical Currents and Transport Studies in HSX at 1 T

Neoclassical Predictions of ‘Electron Root’ Plasmas at HSX

ECE Diagnostic on the HSX Stellarator

Design of Interferometer System

Reduction of Neoclassical Transport and Observation of a Fast Electron Driven Instability with Quasisymmetry in HSX J.M. Canik1, D.L. Brower2, C. Deng2,

Magnetic fluctuation measurements in HSX and its impact on transport

Impurity Transport Research at the HSX Stellarator

in tokamaks and stellarators

S. P. Gerhardt, A. Abdou, A. F. Almagri, D. T. Anderson, F. S. B

Characteristics of Biased Electrode Discharges in HSX

Characteristics of Edge Turbulence in HSX

Overview of Recent Results from HSX

First Experiments Testing the Working Hypothesis in HSX:

Presentation transcript:

Measurement of Electron Density Profile and Fluctuations on HSX C. Deng, D.L. Brower, W.X. Ding Electrical Engineering Department University of California, Los Angeles A.F. Almagri, D.T. Anderson, F.S.B. Anderson, S.P. Gerhardt, P. Probert, J. Radder, J.N. Talmadge The HSX Plasma Laboratory, University of Wisconsin-Madison

Interferometer Capabilities Spatial resolution: 9 chords, 1.5cm spacing and width. Fast time response: analog:  sec, real time digital: <10  sec maximum bandwidth 250 kHz [with 2 MHz sampling] Low phase noise: 24 mrad (1.6 o ) (  n e dl) min = 8 x cm % level density fluctuations can be measured Density fluctuations: wavenumber resolution (i) k  < 2.1 cm -1, (ii) k || < 0.07 cm -1

Solid State Source Solid State Source: –bias-tuned Gunn diode at 96 GHz with passive solid-state Tripler providing output at 288 GHz (8 mW) Support of Optical System: –2.5 meter tall, 1 ton reaction mass, mounted on structure independent of HSX device. Reduces structure vibration and minimizes phase noise. Dichroic Filters: –mounted on port windows to shield interferometer from 28 GHz gyrotron radiation plus, –cutoff frequency: 220 GHz –approximately 10% loss –attenuation ranging from 92db at 28 GHz to 68 db at 150 GHz.

Interferometer Schematic Plasma Phase Comparator Sawtooth Modulator Filter Gunn 96 GHz Tripler 288 GHz Filter Amp. Mixer Lens Detection System 9 channels Probe Reference ∆Ø=∫n e dl

Beam Expansion Optics and Receiver Array

HSX Interferometer Layout

HSX Interferometer System

FFT Spectra Analysis 768 kHz IF sampled at 1 MHz, aliased to 232 kHz Sawtooth frequency modulation of source produces harmonics Unable to remove harmonic components completely with existing electronic filters (70 kHz < passband < 2 MHz at 3 db points).

DPC Phase Noise Including harmonic content in bandwidth of DPC causes phase oscillation Excluding harmonics from DPC bandwidth reduces rms phase noise to 24 mrad (same as analog PC with <10 kHz bw) 100 kHz max. bandwidth with 1 MHz sampling 250 kHz max. bandwidth with 2 MHz sampling

Chord Lengths Magnetic Flux Surfaces and Chord Positions Vacuum Vessel Last Closed Flux Surface

Density Profile Inversion Method: H. K. Park technique; asymmetric Abel inversion - flexible boundary conditions - non-circular geometry - plasma scrape-off-layer SOL estimate Model: spline fit to 9 channel line-density profile - no Shafranov Shift Path lengths: calculated for ten vacuum flux surfaces, SOL plasma contribution: One viewing chord is outside the separatrix. This will provide information on the SOL contributions to other chords. Refraction correction: necessary for chord length and position

HSX Density Profile

Density Profile Time Evolution

Line-Integrated Data for QHS Plasma Shot 35:

Line-Integrated Data for Mirror Mode n e dl (10 13 cm -2 ) time (ms) ECRH off Shot 48:

QHS and Mirror Mode Comparison QHS Mirror Mode

Inverted Density Profiles

QHS and Mirror Mode Density Profiles  mirror mode plasmas have inboard higher density

Profile Changes with ECRH Location  profile shape does not vary with heating location

Profile Changes with Density  profile shape varies little with density

m=1 Density Fluctuations

Frequency Spectra Chord at x = 1 cm

Inverted Density Profiles

Coherence and Phase

Summary Multichannel 288 GHz interferometer system has been installed and is now operating on the HSX stellarator Refraction correction to line-integrated data is required Initial inversions show a peaked density profile, inversion development still in progress Differences between QHS and Mirror Mode plasmas are being evaluated Little profile variation found with changing density or ECRH location For high density plasmas, large-amplitude m=1 oscillations (3 kHz) are often observed

HSX Stellarator Helically Symmetric EXperiment, HSX quasi-helically symmetric [QHS] stellarator major radius: R=1.2 m, average minor radius: = 15 cm, B T = T, Te = 1 keV, and n e < 1 x10 13 cm -3 Heating and breakdown: 28 GHz ECRH, 200 kW Unique toroidal magnetic configuration: no toroidal curvature and a helical axis of symmetry. Physics goals: Greatly reduced neoclassical transport with respect to other stellarators and comparable tokamaks. Reduced anomalous transport by low parallel viscous damping in the direction of symmetry.

Data Acquisition System Analog phase comparator: PCI-MIO-16E-1, 12 bits resolution, maximum sampling rate 75 kHz for 9 channels Digital phase comparator: PCI-6110 E, 12 bits resolution, max sampling rate 5 MHz for 10 channels Control and manage: PC and LabVIEW.

Comparison of Analog and Digital Phase Comparator Output Analog Digital