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Aspects of particle acceleration in solar flares.

机译：太阳耀斑中粒子加速的各个方面。

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摘要

This is a theoretical study of the acceleration of charged particles during solar flares. An attempt is made to trace the relationship between the processes of acceleration and primary flare energy release.; Motion of charged particles in a reconnecting current sheet (RCS) is considered, including both the electric field and the magnetic field with nonzero transverse (perpendicular to the RCS plane) and longitudinal (parallel to the electric current) components. An analytical technique is developed to calculate particle trajectories and energy gain. The solution predicts a critical value of the longitudinal field beyond which it counteracts the effect of the transverse field that serves to eject the particles out of the sheet rapidly.; A longitudinal component on the order of the reconnecting component is necessary to explain electron acceleration in RCSs up to 10-100 keV during the impulsive phase of solar flares. The acceleration time can be sufficiently short ({dollar}approx{dollar}10{dollar}sp{lcub}-6{rcub}{dollar}s) for the process to occur in the regime of impulsive, bursty reconnection. Particle escape turns out to be more efficient across the RCS rather than along it, placing strong requirements on the electric field necessary to accelerate the particles.; Protons can interact with the RCS more than once due to the transverse electric field outside the RCS. This field efficiently "locks" nonthermal ions in the RCS, allowing their acceleration by the direct electric field to an energy of up to a few GeV in less than 0.1 s. This mechanism explains the generation of relativistic ions in large gamma-ray/proton flares.; Electromagnetic ion-cyclotron waves are generated by the electrons in RCSs during impulsive flares. The resonant interaction with these waves is the most promising mechanism for selective acceleration of {dollar}sp3{dollar}He ions. However, the observed break in the particle spectra at energies of about 1-10 MeV cannot be explained by the action of the acceleration mechanism alone. It is shown that Coulomb energy losses may be large enough to provide the observed spectral break. Its position is determined by the balance between energy gain by acceleration and the energy loss.
机译：这是太阳耀斑期间带电粒子加速的理论研究。试图追踪加速过程与初级火炬能量释放之间的关系。考虑了带电粒子在重新连接电流片（RCS）中的运动，包括具有非零的横向（垂直于RCS平面）和纵向（平行于电流）分量的电场和磁场。开发了一种分析技术来计算粒子轨迹和能量增益。该解决方案预测了纵向场的临界值，在该临界值之上，它抵消了横向场的作用，该横向场的作用是将颗粒迅速地喷出薄板。为了说明在太阳耀斑的脉冲阶段，RCS中的电子加速度高达10-100 keV，需要一个重连接分量的纵向分量。加速时间可以足够短（{dollar}约{dollar} 10 {dollar} sp {lcub} -6 {rcub} {dollar} s），以使该过程在脉冲，突发性重新连接状态下发生。事实证明，沿着RCS而不是沿着RCS，粒子逸出更为有效，这对加速粒子产生的电场提出了严格要求。由于RCS外部的横向电场，质子可以多次与RCS相互作用。该场有效地“锁定”了RCS中的非热离子，允许它们在不到0.1 s的时间内被直流电场加速到几GeV的能量。这种机制解释了在大的伽马射线/质子耀斑中相对论离子的产生。脉冲耀斑期间，RCS中的电子会产生电磁离子回旋波。与这些波的共振相互作用是{sp3} sp3 {dollar} He离子选择性加速的最有希望的机制。但是，仅通过加速机制的作用就无法解释在大约1-10 MeV的能量下观察到的粒子光谱破裂。结果表明，库仑能量损失可能足够大以提供观察到的光谱破坏。它的位置取决于加速度获得的能量与能量损失之间的平衡。

著录项

  • 作者

    Litvinenko, Yuri Eduardovich.;

  • 作者单位

    University of New Hampshire.;

  • 授予单位 University of New Hampshire.;
  • 学科 Physics Astronomy and Astrophysics.
  • 学位 Ph.D.
  • 年度 1996
  • 页码 101 p.
  • 总页数 101
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类 天文学;
  • 关键词

  • 入库时间 2022-08-17 11:49:18

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