Nättilä Joonas, Beloborodov Andrei M
Physics Department and Columbia Astrophysics Laboratory, Columbia University, 538 West 120th Street, New York, New York 10027, USA.
Center for Computational Astrophysics, Flatiron Institute, 162 Fifth Avenue, New York, New York 10010, USA.
Phys Rev Lett. 2022 Feb 18;128(7):075101. doi: 10.1103/PhysRevLett.128.075101.
Magnetic energy around astrophysical compact objects can strongly dominate over plasma rest mass. Emission observed from these systems may be fed by dissipation of Alfvén wave turbulence, which cascades to small damping scales, energizing the plasma. We use 3D kinetic simulations to investigate this process. When the cascade is excited naturally, by colliding large-scale Alfvén waves, we observe quasithermal heating with no nonthermal particle acceleration. We also find that the particles are energized along the magnetic field lines and so are poor producers of synchrotron radiation. At low plasma densities, our simulations show the transition to "charge-starved" cascades, with a distinct damping mechanism.
天体物理致密物体周围的磁能可以强烈地超过等离子体静止质量。从这些系统中观测到的辐射可能由阿尔文波湍流的耗散提供能量，这种湍流级联到小的阻尼尺度，为等离子体提供能量。我们使用三维动力学模拟来研究这个过程。当通过碰撞大尺度阿尔文波自然激发级联时，我们观察到准热加热，没有非热粒子加速。我们还发现粒子沿着磁力线被加速，因此是同步辐射的不良产生者。在低等离子体密度下，我们的模拟显示向具有独特阻尼机制的“电荷匮乏”级联的转变。
