Applying B fields on laser-produced shockwaves and jets Dawei Yuan Group for Intense Laser High Energy Density Physics Institute of Physics, Chinese Academy of Sciences LaB workshop @ LULI, 2013-12-04
Collaborators: 1 Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China 2 National Astronomical Observatories, Chinese Academy of Sciences, Beijing 100012, China 3 Institute of Applied Physics and Computational Mathematics, Beijing 100094, China 4 Institute of Laser Engineering, Osaka University, 2-6 Yamada-oka, Suita, Osaka, 565- 0871, Japan 5 Research Center for Laser Fusion, China Academy of Engineering Physics, Mianyang 621900, China 6 National Laboratory on High Power Lasers and Physics, Shanghai, 201800, China 7 Key Laboratory for Laser Plasmas (Ministry of Education) and Department of Physics, Shanghai Jiao Tong University, Shanghai 200240, China
Content: Collisionless shockwave generation at Shengguang-II(SG-II) laser facility Showing results at SG-II in recently years Discussion about results The factors (Ambient medium, Radiation cooling, Magnetic field) effect on the jet collimation in Lab Jet deflection by crosswind produced by hot plasma Weaker B field effect on jet collimation
Collisionless shockwave Collisionless shockwaves are observed in supernova remnant and sun- earth space, etc. Plasma Phys. Control. Fusion Collisionless Shock 50 (2008) 124057 (15pp) Supernova Remnant SN1006 CME Source of sun-wind Origin of cosmic ray Nature Physics/Published online: 6 October 2013
Collisionless shockwave (b) (a) Filamentary Two-stream Plasma Phys. Control. Fusion 50 Weibel (2008) 124057 (15pp) Two types model experiment 1) One-direction laser irradiation Phys. Plasmas 15, 082108 (2008) 2) Counter-beam irradiation The fields via these instabilities supply the necessary dissipation processes for shockwave generation.
Collisionless shockwaves generated at SG-II laser facility Shenguang II Experimental setup SG II 9 th beam used as probe beam, 50mJ, 30fs pulse duration, @ 2 (527nm) . SG II 8 main laser beams with 2 kJ total The delay time range between main beam energy, 1ns pulse duration, @ 3 (351nm) and probe is from 0 ns to 15 ns. The laser intensity: ~4 × 10 15 W/cm 2
Collisionless shock generation in experiment (2009) 5 ns 9 ns Density jump First model-Laser irradiation single CH foil The ion mean free path is ~25-35 mm ， far larger than the density jump region (100 μ m) Collisionless shock T. Morita et al. Phys. Plasmas 17, 122702 (2010)
Evolution of two counter-streaming plasmas(2009-2010) 2 ns 3ns 1 ns Electrostatic shockwave Shockwave decay Laser irradiation pair of CH foils 5ns 9 ns T 1 T 2 Weibel-driven-shockwave ? Ion-Weibel instability ? T 3 X. Liu, et al., New J. Phys. 13 (2011) 093001 D. W. Yuan, et al., High Energy Density Physics 9 (2013) 239-242
Weibel-instability observed in experiment (2011 + 2012) Symmetrical laser irradiation Left:4 beams Right:4beams 5ns Non-symmetrical laser irradiation Left: 3beams Right: 4beams 5ns We confirm that this filaments appear at around 5ns in experiment(repeat it every year) YUAN Dawei et al. Sci China-Phys Mech Astron 56 (2013) 12:1-5
Evolution of two counter-streaming plasmas(2009-2010) 2 ns 3ns 1 ns Electrostatic shockwave Shockwave decay 5ns 9 ns T 1 T 2 Weibel-driven-shockwave ? Ion-Weibel instability ? T 3 X. Liu, et al., New J. Phys. 13 (2011) 093001 D. W. Yuan, et al., High Energy Density Physics 9 (2013) 239-242
Firstly observing two shockwaves generation in experiment (2013) (Preliminary results) (a) (d) y=190 y=190 (b) (e) 5.165 e19 6.417 e19 6.14 e19 S2 S1 S1 S2 120 μ m 200 μ m 96 μ m 1.4 e19 2.742 e19 580 519 559 Y Y (c) (f) X 8 ns 10 ns X
Discussion The linear dispersion relation of the electrostatic mode: Temperature distribution 2 2 2 2 2 ( kc ) k ( v Z ( ) 2 ( V sin ) ( 1 Z ( ))) 0 Ds th , s s s d , s s s s 500 300 ion Temp. electron Temp. ion Temp. 250 electron Temp. 400 200 Temp.(eV)@2 ns Temp.(eV)@3 ns 300 150 200 100 100 Target position 50 0 0 0 100 200 300 400 500 600 700 800 900 1000 0 200 400 600 800 1000 1200 1400 1600 X(um) X(um) The linear growth rate of the elec- The linear growth rate of the electro- trostatic ion-ion instability(ESI) magnetic Weibel-type instability(WBI) Time: ESI is easy to grow up at early stage(before 3 ns), because of the large temperature difference between electron and ion WBI appears at later time(after 3 ns). Space: ESI:~electron inertial depth-~d e = c/ ω pe ~5 -7 μ m « space resolution limit. WBI:~ion inertial depth~ d i = c/ ω pi ~ 100 μ m.
Discussion • From calculation and simulations, it is deduced that the density jump at early time was probably an electrostatic collisionless shock@2 ns. • The length of the filaments observed at later time (for example, 5 ns) which is near to the ion inertial depth. The filaments should be caused by the Weibel instability. Filamentation Instability of counterstreaming Laser-Driven Plasmas W. Fox et al. [Phys.Rev.Lett. 111,255002 (2013)
Discussion t = 5 ns Conditions: SG-II laser facility Optical diagnostics Total energy:2.0 kJ Sensitive to density Laser pulse: 1 ns Wavelength: 3 ω 351 nm Insensitive to CH CH Electromagnetic field Targets material: CH Targets separation: 4.5 mm D. W. Yuan, et al., High Energy Density Physics (2013) YUAN Dawei et al. Sci China-Phys Mech Astron (2013) Conditions: OMEGA EP laser facility Total energy:3.6 kJ Proton radiography Laser pulse: 2 ns technique CH CH Wavelength: 3 ω 351 nm Insensitive to density Targets material: CH Sensitive to Targets separation: 4.5 mm Electromagnetic field W. Fox et al. Phys.Rev.Lett. (2013)
Content: Collisionless shockwave generation at Shengguang-II(SG-II) laser facility Showing results at SG-II in recently years Discussion about results The factors (Ambient medium, Radiation cooling, Magnetic field) effect on the jet collimation in Lab Jet deflection by crosswind produced by hot plasma Weaker B field effect on jet collimation
Astrophysical jet Jets are axially collimated outflows, which are ubiquitous in astrophysics, such as YSOs, AGNs and BH. Physics of jet launch and acceleration ---Constrain the initial condition for jet production Physics of jet collimation, propagation and termination ---Collimation is due to the internal outflow properties or to an interaction with the environment. Ambient Medium jet deflection via hot plasma Radiation cooling Different materials Magnetic field
Jet deflection via hot plasma wind(2012) Figure (a) shows the impact of the crosswind on the jet in lab, which is determined by mean free path of the wind ions interacting with the jet. For the electron density in the jet of n e >5 * 10 18 cm -3 and ionic charge Z >5, one finds λ wj < 2 * 10 -3 cm. Thus, λ wj / R j «1, it is appropriate to use the two-dimensional hydrodynamic numerical simulations. Figure (b) shows the corresponding simulation result at the same delay time with LARED -S codes
Jet deflection via hot plasma wind(2012) We also change the property of crosswind by changing the time difference between laser 1/2 and laser 3. The result indicates that the deflection jet depend on the property of the hot crosswind.
Jet collimated via extra B field(2013) (Preliminary results) PM 15 mm 0.4 mm Permanent 0.8 mm 15 mm 0.4 mm 0.4 mm 0.8 mm 15 mm 0.8 mm magnet(PM) 0.05 mm 0.05 mm 0.05 mm PM 0.8 mm 0.8 mm 0.8 mm B~3000Gs ║ B~0Gs B~3000Gs ┴ (b) (a) (c) T= 2 ns T= 2 ns T= 2 ns B B ~1.6mm ~1.1mm ~1.1mm L: 1600 μ m L: 1100 μ m L: 1100 μ m R: 200 μ m R: 200 μ m R: 80 μ m Much narrower length shorter length shorter
Summary We study the evolution of the two counter-streaming flows. Electrostatic shockwave is observed during the evolution of the two counter-streaming plasmas. shock Filaments via Weibel-type instability is observed. Two shockwaves are firstly observed using two counter- streaming plasmas in experiment. Jet is deflected by the hot plasma crosswind. Jet Weak magnetic field (~kGauss)affect on the jet collimation
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