论文标题
在强磁性旋转偶极子中的颗粒加速度和辐射反应
Particle acceleration and radiation reaction in a strongly magnetized rotating dipole
论文作者
论文摘要
简略。中子恒星被超强的颗粒围绕，可有效地通过超强的电磁场加速。然而，到目前为止，尚无数值模拟能够处理如此高的洛伦兹因素和磁场强度的极端机制。本文的目的是在旋转的磁偶极子中研究颗粒加速度和辐射反应，并具有典型的毫秒和年轻脉冲星以及磁铁的典型磁场强度。为此，我们实现了一个精确的分析粒子推动器，包括在还原的Landau-Lifshitz近似中，其中电磁场在一个时间阶段积分中的时间恒定而均匀。位置更新是使用速度Verlet方法执行的。我们对算法进行了广泛的测试，以独立的背景电磁场，例如交叉电场和磁场中的电漂移以及偶极子中的磁性漂移和镜像运动。最终，我们将其应用于现实的中子星环境。我们研究了粒子的加速度以及围绕毫秒脉冲星，幼脉冲和磁铁的电子，质子和铁核的辐射反应的影响，将其与没有辐射反应的情况进行了比较。我们发现，最大洛伦兹因子取决于粒子物种，但仅弱于中子恒星类型。电子达到$γ_e\ \最大的能量，大约10^8-10^9 $，而质子的能量高达$γ_p\ of $γ_p\大约10^5-10^6 $，并熨烫高达$γ\ of 10^4-10^5 $。虽然质子和铁不受辐射反应的影响，但电子被大大减速，将其最大洛伦兹因子降低了2个数量级。我们还发现，辐射反应极限轨迹与几乎所有情况下的Landau-Lifshitz近似值相当一致。
Abridged. Neutron stars are surrounded by ultra-relativistic particles efficiently accelerated by ultra strong electromagnetic fields. However so far, no numerical simulations were able to handle such extreme regimes of very high Lorentz factors and magnetic field strengths. It is the purpose of this paper to study particle acceleration and radiation reaction damping in a rotating magnetic dipole with realistic field strengths typical of millisecond and young pulsars as well as of magnetars. To this end, we implemented an exact analytical particle pusher including radiation reaction in the reduced Landau-Lifshitz approximation where the electromagnetic field is assumed constant in time and uniform in space during one time step integration. The position update is performed using a velocity Verlet method. We extensively tested our algorithm against time independent background electromagnetic fields like the electric drift in cross electric and magnetic fields and the magnetic drift and mirror motion in a dipole. Eventually, we apply it to realistic neutron star environments. We investigated particle acceleration and the impact of radiation reaction for electrons, protons and iron nuclei plunged around millisecond pulsars, young pulsars and magnetars, comparing it to situations without radiation reaction. We found that the maximum Lorentz factor depends on the particle species but only weakly on the neutron star type. Electrons reach energies up to $γ_e \approx 10^8-10^9$ whereas protons energies up to $γ_p \approx 10^5-10^6$ and iron up to $γ\approx 10^4-10^5$. While protons and irons are not affected by radiation reaction, electrons are drastically decelerated, reducing their maximum Lorentz factor by 2 orders of magnitude. We also found that the radiation reaction limit trajectories fairly agree with the reduced Landau-Lifshitz approximation in almost all cases.
