论文标题
相对论的alfvén波在中子星的磁层中进入电荷饥饿
Relativistic Alfvén Waves Entering Charge Starvation in the Magnetospheres of Neutron Stars
论文作者
论文摘要
中子恒星中的不稳定性可以在其磁层中产生Alfvén波。沿弯曲磁场线的传播强烈剪切波浪，增强其电流$ j _ {\ rm a} $。我们得出了波动矢量$ \ boldsymbol {k} $的演变的分析表达式和$ j _ {\ rm a} $的增长。在强烈的剪切制度中，$ j _ {\ rm a} $可能会超过可由背景$ e^{\ pm} $ plasma支持的最大当前$ j_ {0} $。我们首先使用简化的两流体分析模型，然后使用第一原理动力学模拟研究了这些“电荷饥饿”波。我们发现，即使$κ\ equiv j _ {\ rm a}/j_ {0} \ gg 1 $，alfvén波仍继续成功地传播。它通过用粒子lorentz因子$ \simκ^{1/2} $压缩和推进等离子体来维持$ j _ {\ rm a} $。该模拟显示了血浆不稳定性如何导致波能逐渐耗散，从而给出了耗散功率$ l _ {\ rm diss} \ sim 10^{35} {35}（κ/100）^{1/2}（b_w/10^{11}}}}}波幅度。我们的结果表明，与最近的建议相比，由于电荷饥饿引起的耗散不足以为观察到的快速无线电爆发（FRB）供电。
Instabilities in a neutron star can generate Alfvén waves in its magnetosphere. Propagation along the curved magnetic field lines strongly shears the wave, boosting its electric current $j_{\rm A}$. We derive an analytic expression for the evolution of the wave vector $\boldsymbol{k}$ and the growth of $j_{\rm A}$. In the strongly sheared regime, $j_{\rm A}$ may exceed the maximum current $j_{0}$ that can be supported by the background $e^{\pm}$ plasma. We investigate these "charge-starved" waves, first using a simplified two-fluid analytic model, then with first-principles kinetic simulations. We find that the Alfvén wave continues to propagate successfully even when $κ\equiv j_{\rm A}/j_{0} \gg 1$. It sustains $j_{\rm A}$ by compressing and advecting the plasma along the magnetic field lines with particle Lorentz factors $\sim κ^{1/2}$. The simulations show how plasma instabilities lead to gradual dissipation of the wave energy, giving a dissipation power $L_{\rm diss}\sim 10^{35}(κ/100)^{1/2} (B_w/10^{11}\,{\rm G})\,\mathrm{erg/s}$, where $B_w$ is the wave amplitude. Our results imply that dissipation due to charge starvation is not sufficient to power observed fast radio bursts (FRBs), in contrast to recent proposals.
