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Electron Surfing Acceleration in Current Sheet of Flares . Wang De Yu* Lu Quan Ming** *Purple Mountain Observatory, Nanjing **University of Science and Technology in China, Hefei. Electron acceleration in the magnetic reconnection of flare.

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Electron surfing acceleration in current sheet of flares l.jpg

Electron Surfing Acceleration in Current Sheet of Flares

Wang De Yu* Lu Quan Ming**

*Purple Mountain Observatory, Nanjing

**University of Science and Technology in China, Hefei


Electron acceleration in the magnetic reconnection of flare l.jpg
Electron acceleration in the magnetic reconnection of flare

  • (a) Electric field and induced electric field acceleration.

  • Litvinenko et al. (1993)

  • (b) Shock wave acceleration.

  • Somov et al (1997)

  • (c) Turbulence acceleration

  • Miller (1997)


Some electrostatic waves can be excited during the magnetic reconnection l.jpg
Some electrostatic waves can be excited during the magnetic reconnection

  • It is found from three dimensional particle simulation that

  • some perpendicular propagating electrostatic waves can be excited during the magnetic reconnection

  • Two examples:


Lower hybrid drift wave l.jpg
Lower Hybrid Drift Wave reconnection

Horiuchi and Sato (1999)


Fourier spectrum of lower hybrid drift wave l.jpg
Fourier Spectrum of Lower Hybrid Drift Wave reconnection

Horiuchi and Sato (1999)


Buneman instability langmuir wave l.jpg
Buneman Instability ( Langmuir Wave ) reconnection

Drake et al. (2003)


Slide8 l.jpg


Slide10 l.jpg

Sketch of of electrostatic wave.perpendicular propagatingelectrostatic wave in magnetic reconnection


Wave frame l.jpg
Wave Frame of electrostatic wave.


Slide13 l.jpg

Analytical approximation solution of electrostatic wave.


Slide14 l.jpg

Vx of electrostatic wave.

Vz

Vz

Vx


Slide15 l.jpg

Particle of electrostatic wave.

Particle simulation

G>0


Slide16 l.jpg

Particle Simulation of electrostatic wave.


Slide17 l.jpg

S of electrostatic wave.

S

Vx

S

For different E0

Vz


Discussion l.jpg
Discussion of electrostatic wave.

  • The surfing acceleration for different amplitude E0 of electrostatic wave is different. A larger E0 is provided with a deeper trapping potential, it makes an electron can be accelerated to higher energy.

(2) A growing surfing acceleration velocity curve of Vx has a turning point S. That means the test electron de- trap from the potential of electrostatic wave at this point, and then, the test electron cannot be accelerated continuously in the current sheet by electrostatic wave.

(3) The limited surfing acceleration velocity and acceleration time.

The first term in the right hand of above equation is a trapping term, the second and third term in the right hand are de-trapping terms. When Fy -- 0, the turning point is an equilibrium about trapping term and de-trapping term.

(a) Longitudinal magnetic field By-- 0, it is found Vz--0, so that the third term in above equation approaches to zero.


Slide19 l.jpg


Particle simulation for different by 0 l.jpg
Particle simulation for different By< 0 other in the above equation.


Slide21 l.jpg

Spectrum of electron surfing acceleration other in the above equation.


Slide22 l.jpg

  • IV. Conclusion other in the above equation.

  • The electron can be rapidly accelerated by perpendicular propagating electrostatic waves during the collisionless magnetic reconnection.

  • The electron can be effectively accelerated by perpendicular propagating electrostatic waves only in the case of G > 0. The velocity of acceleration electron in the x direction is approximate to .

  • The electron acceleration are limited by the de- trapping from the potential of electrostatic waves; the electron escape from the boundary of reconnection sheet and nonlinear evolution of electrostatic waves.

  • Therefore, the electron acceleration by perpendicular propagating electrostatic waves should be a short period acceleration processes during the early stage of collisionless magnetic reconnection.


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