Magnetic field annihilation and reconnection driven by femtosecond lasers in inhomogeneous plasma

Abstract

The process of fast magnetic reconnection driven by intense ultra-short laser pulses in underdense plasma is investigated by particle-in-cell simulations. In the wakefield of such laser pulses, quasi-static magnetic fields at a few mega-Gauss are generated due to nonvanishing cross product ∆(n /γ) × p. Excited in an inhomogeneous plasma of decreasing density, the quasi-static magnetic field structure is shown to drift quickly both in lateral and longitudinal directions. When two parallel-propagating laser pulses with close focal spot separation are used, such field drifts can develop into magnetic reconnection (annihilation) in their overlapping region, resulting in the conversion of magnetic energy to kinetic energy of particles. The reconnection rate is found to be much higher than the value obtained in the Hall magnetic reconnection model. Our work proposes a potential way to study magnetic reconnection-related physics with short-pulse lasers of terawatt peak power only

On annihilation of the relativistic electron vortex pair in collisionless plasmas

“…It was demonstrated that the magnetic field damping in the non-relativistic case is at least three times longer, and the electric fields coming from the displacement current term in Ampere’s law are negligible, see Wang et al. (2016).…”

“…2016; Wang et al. 2016). In the case of our simulations, the ratio of the term to the current term with the increased density can be written as (by an order of magnitude): , where accounts for possible increase of the current due to the increase in electron density with in our simulations.…”

Splitter target for controlling magnetic reconnection in relativistic laser plasma interactions

“…In the cases of astrophysical and laboratory plasmas, the magnetic reconnection plays a key role in a broad range of processes exemplified by solar flares [6][7][8], coronal mass ejections [9,10], open and closed planetary magnetospheres [11][12][13], gamma-ray bursts [14][15][16][17] and nuclear fusion plasma instabilities [18][19][20][21]. Due to the recent progress in laser technology, high power lasers were employed to study the fast magnetic reconnection regime [22][23][24][25][26][27]. In fact, when a high-intensity laser pulse interacts with a plasma target the accelerated electron bunches generate strong magnetic fields with non-trivial topology.…”