The study of NBI-driven AE chirping mode

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

ASIPP Characteristics of edge localized modes in the superconducting tokamak EAST M. Jiang Institute of Plasma Physics Chinese Academy of Sciences The.

M. Zuin 14th IEA RFP workshop, Padova, April, 26-28, 2010 Alfvén eigenmodes in RFX-mod M. Zuin, S. Spagnolo, E. Martines, B. Momo, R. Cavazzana, M. Spolaore,

Analysis of instrumental effects in HIBP equilibrium potential profile measurements on the MST-RFP Xiaolin Zhang Plasma Dynamics Lab, Rensselaer Polytechnic.

Results from Visible Light Imaging of Alfvén Fluctuations in the H-1NF Heliac J. Read, J. Howard, B. Blackwell, David Oliver, & David Pretty Acknowledgements:

#0 F. Castejón 1), M. Ochando 1), T. Estrada 1), M.A. Pedrosa 1), D. López-Bruna 1), E. Ascasíbar 1), A. Cappa 1), A.A. Chmyga 2), N.B Dreval 2), S. Eguilior.

Plasma Dynamics Lab HIBP Abstract Measurements of the radial equilibrium potential profiles have been successfully obtained with a Heavy Ion Beam Probe.

Outline (HIBP) diagnostics in the MST-RFP Relationship of equilibrium potential measurements with plasma parameters Simulation with a finite-sized beam.

SUMMARY OF EXPERIMENTAL CORE TURBULENCE CHARACTERISTICS IN OH AND ECRH T-10 TOKAMAK PLASMAS V. Vershkov, L.G. Eliseev, S.A. Grashin. A.V. Melnikov, D.A.

D. Borba 1 21 st IAEA Fusion Energy Conference, Chengdu China 21 st October 2006 Excitation of Alfvén eigenmodes with sub-Alfvénic neutral beam ions in.

Fast imaging of global eigenmodes in the H-1 heliac ABSTRACT We report a study of coherent plasma instabilities in the H-1 plasma using a synchronous gated.

Parallel and Poloidal Sheared Flows close to Instability Threshold in the TJ-II Stellarator M. A. Pedrosa, C. Hidalgo, B. Gonçalves*, E. Ascasibar, T.

Experimental Progress on Zonal Flow Physics in Toroidal Plasmas

Initial wave-field measurements in the Material Diagnostic Facility (MDF) Introduction : The Plasma Research Laboratory at the Australian National University.

H. Urano, H. Takenaga, T. Fujita, Y. Kamada, K. Kamiya, Y. Koide, N. Oyama, M. Yoshida and the JT-60 Team Japan Atomic Energy Agency JT-60U Tokamak: p.

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,

J A Snipes, 6 th ITPA MHD Topical Group Meeting, Tarragona, Spain 4 – 6 July 2005 TAE Damping Rates on Alcator C-Mod Compared with Nova-K J A Snipes *,

Edge Localized Modes propagation and fluctuations in the JET SOL region presented by Bruno Gonçalves EURATOM/IST, Portugal.

Excitation of ion temperature gradient and trapped electron modes in HL-2A tokamak The 3 th Annual Workshop on Fusion Simulation and Theory, Hefei, March.

HAGIS Code Lynton Appel … on behalf of Simon Pinches and the HAGIS users CCFE is the fusion research arm of the United Kingdom Atomic Energy Authority.

Plasma Dynamics Lab HIBP E ~ 0 V/m in Locked Discharges Average potential ~ 580 V  ~ V less than in standard rotating plasmas Drop in potential.

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

NSTX-U NSTX-U PAC-31 Response to Questions – Day 1 Summary of Answers Q: Maximum pulse length at 1MA, 0.75T, 1 st year parameters? –A1: Full 5 seconds.

High  p experiments in JET and access to Type II/grassy ELMs G Saibene and JET TF S1 and TF S2 contributors Special thanks to to Drs Y Kamada and N Oyama.

1 Confinement Studies on TJ-II Stellarator with OH Induced Current F. Castejón, D. López-Bruna, T. Estrada, J. Romero and E. Ascasíbar Laboratorio Nacional.

Investigation of fast ion mode spatial structure in NSTX N.A. Crocker, S. Kubota, W.A. Peebles (UCLA); E.D. Fredrickson, N.N. Gorelenkov, G.J. Kramer,

TJ-II Results from Helical Axis Stellarators - ICPP 2000 TJ-II Heliac, CIEMAT, Spain R = 1.5 m, a < 0.22 m, 4 periods B 0 < 1.2 T P ECRH < 600 kW from.

(National Institute for Fusion Science, Japan)

Edge and Internal Transport Barrier Formations in CHS S. Okamura, T. Minami, T. Akiyama, T. Oishi 1, A. Fujisawa, K. Ida, H. Iguchi, M. Isobe, S. Kado.

Probe measurements on the GOLEM tokamak Vojtech Svoboda 1, Miglena Dimitrova 2, Jan Stockel 1,2 1 Faculty of Nuclear Physics and Physical Engineering,

U NIVERSITY OF S CIENCE AND T ECHNOLOGY OF C HINA CAS K EY L ABORATORY OF B ASIC P LASMA P HYSICS Recent experimental results of zonal flows in edge tokamak.

Active Control of MHDinstabilitiy 2002/11/19 S.Ohdachi et.al. Sawtooth-like phenomena in LHD S. Ohdachi, S.Yamamoto, K. Toi, K. Y.Watanabe, S.Sakakibara,

THE BEHAVIOUR OF THE HEAT CONDUCTIVITY COEFFICIENT AND THE HEAT CONVECTIVE VELOCITY AFTER ECRH SWITCH-ON (-OFF) IN T-10 V. F. Andreev, Yu. N. Dnestrovskij,

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.

1 Stability Studies Plans (FY11) E. Fredrickson, For the NCSX Team NCSX Research Forum Dec. 7, 2006 NCSX.

MCZ Active MHD Control Needs in Helical Configurations M.C. Zarnstorff 1 Presented by E. Fredrickson 1 With thanks to A. Weller 2, J. Geiger 2,

Role of thermal instabilities and anomalous transport in the density limit M.Z.Tokar, F.A.Kelly, Y.Liang, X.Loozen Institut für Plasmaphysik, Forschungszentrum.

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.

Measurement of fast ion losses due to MHD modes driven by fast ions in the Large Helical Device 2009/03 Kunihiro OGAWA A, Mitsutaka ISOBE, Kazuo TOI, LHD.

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,

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.

Effect of Energetic-Ion/Bulk-Plasma- driven MHD Instabilities on Energetic Ion Loss in the Large Helical Device Kunihiro OGAWA, Mitsutaka ISOBE, Kazuo.

Simulation of Turbulence in FTU M. Romanelli, M De Benedetti, A Thyagaraja* *UKAEA, Culham Sciance Centre, UK Associazione.

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

Energetic ion excited long-lasting “sword” modes in tokamak plasmas with low magnetic shear Speaker:RuiBin Zhang Advisor:Xiaogang Wang School of Physics,

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

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

Reconnection Process in Sawtooth Crash in the Core of Tokamak Plasmas Hyeon K. Park Ulsan National Institute of Science and Technology, Ulsan, Korea National.

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

Neoclassical Predictions of ‘Electron Root’ Plasmas at HSX

Turbulence wave number spectra reconstruction

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

Huishan Cai, Jintao Cao, Ding Li

15TH WORKSHOP ON MHD STABILITY CONTROL

11th IAEA Technical Meeting on H-mode Physics and Transport Barriers" , September, 2007 Tsukuba International Congress Center "EPOCHAL Tsukuba",

Integrated discharge scenario

Center for Plasma Edge Simulation

Transport, stability and plasma control studies in the TJ-II stellarator presented by J. Sánchez Laboratorio Nacional de Fusión, CIEMAT and collaborators.

2/13 Introduction Knowledge of the influence of the hydrogen isotope on H-mode confinement is essential for accurately projecting the energy confinement.

First Experiments Testing the Working Hypothesis in HSX:

Investigation of triggering mechanisms for internal transport barriers in Alcator C-Mod K. Zhurovich C. Fiore, D. Ernst, P. Bonoli, M. Greenwald, A. Hubbard,

Influence of energetic ions on neoclassical tearing modes

T. Morisaki1,3 and the LHD Experiment Group

Stabilization of m/n=1/1 fishbone by ECRH

NATIONAL RESEARCH CENTER “KURCHATOV INSTITUTE”

T. Morisaki1,3 and the LHD Experiment Group

H. Nakano1,3, S. Murakami5, K. Ida1,3, M. Yoshinuma1,3, S. Ohdachi1,3,

Presentation transcript:

The study of NBI-driven AE chirping mode properties and radial location by Heavy Ion Beam Probe in the TJ-II stellarator A.V. Melnikov1, 2, E. Ascasibar3, A. Cappa3, F. Castejon3, L.G. Eliseev1, C. Hidalgo3, A.S. Kozachek4, L.I. Krupnik4, M. Liniers3, S.E.Lysenko1, J.L. dePablos3, S.V. Perfilov1, S. Sharapov5, V.N. Zenin1, HIBP group1, 3, 4 and TJ-II team2 1 National Research Centre “Kurchatov Institute”, 123182, Moscow, Russia 2 National Research Nuclear University “MEPhI”, Moscow, Russia 3 Fusion National Laboratory, CIEMAT, 28040, Madrid, Spain 4 Institute of Plasma Physics, NSC KIPT, 310108, Kharkov, Ukraine 5 CCFE, Culham Sience Centre, Culham, UK Acknowledgement to K. Nagaoka, S. Yamamoto, T. Ido, A. Shimizu, S. Oshima. 14-th IAEA TM on Energetic Particles in Fusion Plasmas, O-18, 04.09.2015

Motivation 1. AEs induced by alpha-particles and fast ions created by auxiliary heating are capable to cause losses of the fast ions in magnetic fusion devices. 2. It is also believed that chirping modes may affect fast ions in different way than “standard” steady frequency AE ( convective vs diffusive transport). 3. It was found that ECRH induces chirping modes in NBI-heated plasma [P. Lauber et al, 2014 AUG; K. Nagaoka et al, 2013 TJ-II, A. Cappa et al, 2014 TJ-II]. 4. The aim of this study is to investigate the properties and location of the chirping modes in TJ-II stellarator and to identify the conditions of the chirping – steady frequency AE transformation.

Layout I. Introduction. TJ-II stellarator. HIBP schematic and principles II. Potential/density/Bpol oscillations associated to Alfven Eigenmodes. Mode observation and radial location NBI+ECRH NBI-only III. Iota effect IV. Summary. / 35

Experimental Set-up in TJ-II TJ-II is a four-field-period low-magnetic shear stellarator with helical axis. <R> = 1.5 m <a> ≤ 0.22 m B0 = 0.95 T <ne> = 0.3–7.0x1019 m-3 PECRH = 0.3 – 0.6 MW PNBI = 0.45 – 1.1 MW port through

TJ-II ECRH + NBI plasma discharges <ne> = 0. 3 – 4.0x1019 m-3 Hydrogen Te(0) = 1.0 – 0.25 keV Ti(0) = 0.08 – 0.15 keV PECRH = 0.6 MW off axis PNBI = 0.45 – 1.1 MW (Co +Cntr) H0 EH0 < 32 kV , Vbeam ~ 0.36 VA Subalfvenic NBI Sideband resonances play a role Almost shearless configuration <ne> < 1.0x1019 m-3

Achieved bandwidth f < 350 kHz HIBP on TJ-II Beam characteristics Plasma parameters ΔЕbeam  -> Er ~I beam ~ne ~Z ~Bpol SV Achieved bandwidth f < 350 kHz *Fixed point measurements: (r0, t) *Radial scan: (r, t) *Multiple slit measurements: Poloidal sample volume orientation: Ep =(1-2)/x, x~1 cm. Turbulent particle flux r =EpolxBtor= < ne~ vr~> = ExB, HIBP – direct tool for local internal study of АЕ [A.V.Melnikov et al. NF 2010]

NBI+ECRH. Direct chirping mode observation in the core plasmas by HIBP HIBP Bpol MP Bpol CohHIBP MP <ne> < 0.6 x1019 m-3 High coherence (Coh ~ 0.9) between Bpol oscillations (HIBP) at SV = 0.6 and Mirnov probes signals is observed for chirping modes.

NBI+ECRH. Chirping mode radial location - I. Radial scan by sample volume Radial scan variation of the sample volume position over all plasma cross-section, scanning time is 18 ms; PSD for HIBP Bpol indicates the inner border of specific AE at = 0.4; Mirnov probe spectrogram shows the AE exists all the scanning time; Spectrogram of the coherence between density and Mirnov probes signal. High coh in (d) designates the area of the mode location -0.4 < r < -0.8 (High Field Side). Chirping mode has antiballooning structure in HIBP Bpol

NBI+ECRH. Chirping mode radial location - II. Radial scan Coherence between MP and HIBP density; Coherence between MP and HIBP potential; Coherence between MP and HIBP Bpol; High coherence designates the area of the mode location -0.8 < r < +0.8. HIBP shows that chirping mode seemingly has antiballooning structure in Bpol , BUT it has a ballooning structure in j and is nearly symmetric in density

Chirping mode transformation to steady frequency mode after ECRH AE-mode transformation after ECRH switch-off. The overall Alfven-like density dependence from chirping to steady form is remarkable Fine details of the mode transformation: steady AEs appear after some time delay around 2 ms with respect to the ECRH switch-off. Steady AE mode has poloidally symmetrical structure for every perturbed quantity [ Melnikov A.V. et al, NF 2014]

NBI-only plasma: chirping AE modes seen in the core potential #38236 HIBP II slit 3 , (r0, t) Pronounced chirping modes were also observed in the low-density discharges with NBI-only heating. Chirping modes are very similar to the ones observed in NBI+ECRH. <ne> < 0.6 x1019 m-3 Thus, ECRH is not a necessary ingredient to obtain chirping modes, rather a factor affecting plasma profiles ( density and temperature ).

NBI-only plasma: chirping AE modes seen in the perturbed density #38236 HIBP II slit 3 Itot signal (density)

NBI-only plasma: chirping AE modes seen in Bpol 38236 HIBP II slit 3 Zd ~ B

NBI-only plasma: chirping AE evolution with iota as observed by HIBP In the series of similar shots the vacuum iota had tiny changes from shot to shot. The AE modes behavior changes accordingly. Plasma current Ip dynamics changes accordingly.

NBI-only plasma: the mode frequency modeling Plasma density is almost constant at t=1020-1080, while the only Ipl evolves slightly . The mode frequency evolves from ~330 to ~ 80 kHz due to the iota evolution caused by Ipl. ne Ipl Single helicity Linear link to Ipl #38238 HIBP2 slit 3 : Itot [Melnikov A.V. et al, NF 2014] There are two candidates to describe the observations : m/n = 5/8 located @ r ~ 0.75-0.85 m/n = 8/13 located @ r ~ 0.85-0.95 For each candidate the modeled frequency fits the observed frequency within the experimental error bars.

Chirping AE evolution with iota as observed by Mirnov Probes NBI-only plasma Chirping AE evolution with iota as observed by Mirnov Probes Co - NBI ## 38221-37 In the series of similar shots, Ipl(t) is slightly shifted (delayed) with respect to each other. The times when Ipl (and iota) reaches certain value are delayed and the times when transformation occurs are also delayed. There are iota windows favorable for chirping modes and windows favorable for steady modes Ipl (t) Iota windows

NBI-only plasma: Iota effect on chirping characteristics #38221-37 MID5P5 The amplitude of the frequency chirping is evolving (decreasing) with iota evolution (raise) due to the Ipl raise. There are iota windows favorable for chirping modes and windows favorable for steady modes.

NBI-only plasma. Radial location of the chirping mode in a single shot. HFS LFS Similar to NBI+ ECRH: Chirping mode has clear ballooning structure in j, it is slightly asymmetric in density and seems to have antiballooning structure in Bpol

ECRH+NBI: Chirping mode evolution with iota variation Iota vac variation experiment a) PSD of the HIBP Bpol, rSV = -0.73 b) PSD of the MP signal c) Coherency HIBP- MP <ne> = 0.6 - 0.8 x1019 m-3 d) time traces of the plasma parameters. Again: there are iota windows favorable for chirping modes and windows favorable for steady modes

Mode amplitude evolution SV = 0.6? Three modes reach the maximum of the amplitudes simultaneously - at the time of the local minimum of plasma current (iota). Ipl Ipl changes less than 10%?

Chirping in ECRH & NBI ECRH NBI #33238 ECRH NBI Chirping modes always happen in ECRH+NBI and also happen in pure NBI at specific Ipl or iota windows.

Summary The TJ-II experiments with low-density NBI+ECRH and with NBI-only plasma have shown that for frequency range < 400 kHz: 1) chirping modes are almost always observed in NBI + ECRH plasmas, so ECRH seems to be a sufficient condition for obtaining the chirping modes, 2) chirping modes are also observed in NBI-only plasmas, so ECRH is not a necessary condition for obtaining the chirping modes, 3) for some modes, there are iota windows favorable for chirping state and iota windows favorable for steady frequency state for both ECRH+NBI and for NBI-only plasmas, 4) the long-time evolution of the mode frequency in all cases ( chirping, steady and transitions between them) follows a single helicity model with a linear iota dependence on Ipl . 5) the frequency range of the bursts evolves with iota. On TJ-II, the dominant effect on the non-linear evolution of the AE from the chirping state to the steady frequency state is magnetic configuration, determined by iota_vac and Ipl.