The heliospheric ambipolar potential inferred from sunward-propagating halo electrons
The heliospheric ambipolar potential inferred from sunward-propagating halo electrons
复制标题
从向太阳传播的晕电子推断的日光层双极电势
DOI：
10.1093/mnras/stac2051
复制
发表时间：
2022
影响因子：
4.8
通讯作者：
Boldyrev, Stanislav
中科院分区：
文献类型：
--
作者：
Horaites, Konstantinos;Boldyrev, Stanislav
我们提供的证据表明，太阳风电子晕分布中向太阳传播的一半是在内日光层中没有散射的情况下演化的。我们假设粒子保持总能量和磁矩不变，并对帕克太阳探测器SPAN-E仪器测量的电子俯仰角分布进行‘刘维尔映射’。也就是说，如果选择适当的行星际势能，这些分布与刘维尔定理是一致的。这个势是我们拟合方法的一个结果，它与质子体流能量的径向分布进行了比较。我们发现，在日心距0.18-0.79AU的太阳风中，推测势是造成近100% 质子加速的原因。这些观测结合在一起形成了一幅连贯的物理图景：同样的行星际势解释了太阳风质子的加速以及电子晕的演化。在这张照片中，这个光晕是由一个向着太阳传播的群体形成的，这个群体起源于外层日光层的某个地方，机制尚不清楚。
We provide evidence that the sunward-propagating half of the solar wind electron halo distribution evolves without scattering in the inner heliosphere. We assume the particles conserve their total energy and magnetic moment, and perform a ‘Liouville mapping’ on electron pitch angle distributions measured by the Parker Solar Probe SPAN-E instrument. Namely, we show that the distributions are consistent with Liouville’s theorem if an appropriate interplanetary potential is chosen. This potential, an outcome of our fitting method, is compared against the radial profiles of proton bulk flow energy. We find that the inferred potential is responsible for nearly 100 per cent of the proton acceleration in the solar wind at heliocentric distances 0.18-0.79 AU. These observations combine to form a coherent physical picture: the same interplanetary potential accounts for the acceleration of the solar wind protons as well as the evolution of the electron halo. In this picture the halo is formed from a sunward-propagating population that originates somewhere in the outer heliosphere by a yet-unknown mechanism.