论文标题
关于SEP电子光谱的形状：星际转运的作用
On the shape of SEP electron spectra: The role of interplanetary transport
论文作者
论文摘要
我们使用i）观察和ii）建模方法来解决粒子散射对太阳能电子事件的能能光谱的影响。 i）我们从统计上研究了立体上航天器的观察结果，利用使用SEPT仪器在45-425 KEV范围内进行的定向电子测量值。我们将反肺传播光束的能量光谱与向后散射的人群之一进行比较，并发现，平均而言，向后散射的种群显示出较难的光谱，在较高能量下的效果更强。 ii）我们使用数值SEP传输模型来模拟频谱对粒子散射（在俯仰角和垂直于平均场的垂直方面）的影响。我们发现，俯仰角散射会导致较高能量（E $> 100 $ keV）的光谱变化，并且距离太阳（r $> 1 $ au）更远，这也经常被观察到。在较低的能量，更靠近太阳下，俯仰角散射的效果大大降低，因此模拟的能量光谱仍然类似于注射的幂律功能。在检查倾向依赖性光谱时，我们发现，与观察结果一致，向后传播电子的光谱比向前（来自太阳）传播种群的光谱更难。 {我们得出的结论是，{\ it太阳轨道}和{\ it Parker太阳探针}将能够观察到在较高能量的靠近太阳附近的未经调制的Omni方向SEP电子光谱，从而直接指示加速频谱。 }
We address the effect of particle scattering on the energy spectra of solar energetic electron events using i) an observational and ii) a modeling approach. i) We statistically study observations of the STEREO spacecraft making use of directional electron measurements made with the SEPT instrument in the range of 45 -- 425 keV. We compare the energy spectra of the anti-sunward propagating beam with that one of the backward scattered population and find that, on average, the backward scattered population shows a harder spectrum with the effect being stronger at higher energies. ii) We use a numerical SEP transport model to simulate the effect of particle scattering (both in terms of pitch-angle and perpendicular to the mean field) on the spectrum. We find that pitch-angle scattering can lead to spectral changes at higher energies (E $>100$ keV) and further away from the Sun (r $> 1$ au) which are also often observed. At lower energies, and closer to the Sun the effect of pitch-angle scattering is much reduced so that the simulated energy spectra still resemble the injected power-law functions. When examining pitch-angle dependent spectra, we find, in agreement with the observational results, that the spectra of the backward propagating electrons are harder than that of the forward (from the Sun) propagating population. {We conclude that {\it Solar Orbiter} and {\it Parker Solar Probe} will be able to observe the unmodulated omni-directional SEP electron spectrum close to the Sun at higher energies, giving a direct indication of the accelerated spectrum. }
