The Helium Warm Breeze in IBEX Observations As a Result of Charge-exchange Collisions in the Outer Heliosheath
The Helium Warm Breeze in IBEX Observations As a Result of Charge-exchange Collisions in the Outer Heliosheath
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DOI：
10.3847/1538-4357/aa7ed5
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发表时间：
2017-08-10
影响因子：
4.9
通讯作者：
Grygorczuk, Jolanta
中科院分区：
文献类型：
--
作者：
Bzowski, Maciej;Kubiak, Marzena A.;Grygorczuk, Jolanta
我们模拟的信号，由于中性氦原子，观察到的星际边界探测器（IBEX），假设中性氦原子和He+离子之间的电荷交换碰撞操作无处不在之间的太阳风顶和遥远的源区在本地星际云，中性和带电的组件处于热平衡。我们模拟了几个测试情况下的等离子体流的外日鞘（OHS）和研究的信号产生的等离子体流的存在和不存在的星际磁场（ISMF）。我们发现，一个信号的IBEX数据的一部分被确定为是由于温暖的微风（WB）不会出现时，假设在前面的太阳层顶的均匀等离子体流，但它立即出现时，任何合理的扰动，由于日光层的存在，它的流量被假定。我们得到了一个很好的定性协议之间的数据选择比较和模拟的模型流与未扰动气体的速度矢量和磁场的方向和强度通过从最近的测定。我们的结论是，直接采样观察中性氦原子在1 Au从太阳是一个敏感的工具，调查星际物质的流动在OHS，WB确实是星际氦的第二人口，这是假设较早，WB信号是一致的，从轴对称扭曲的日球层的ISMF。
We simulated the signal due to neutral He atoms, observed by the Interstellar Boundary Explorer (IBEX), assuming that charge-exchange collisions between neutral He atoms and He+ ions operate everywhere between the heliopause and a distant source region in the local interstellar cloud, where the neutral and charged components are in thermal equilibrium. We simulated several test cases of the plasma flow within the outer heliosheath (OHS) and investigated the signal generation for plasma flows both in the absence and in the presence of the interstellar magnetic field (ISMF). We found that a signal in the portion of IBEX data identified as being due to the Warm Breeze (WB) does not arise when a homogeneous plasma flow in front of the heliopause is assumed, but it appears immediately when any reasonable disturbance in its flow due to the presence of the heliosphere is assumed. We obtained a good qualitative agreement between the data selected for comparison and the simulations for a model flow with the velocity vector of the unperturbed gas and the direction and intensity of magnetic field adopted from recent determinations. We conclude that direct-sampling observations of neutral He atoms at 1 au from the Sun are a sensitive tool for investigating the flow of interstellar matter in the OHS, that the WB is indeed the secondary population of interstellar helium, which was hypothesized earlier, and that the WB signal is consistent with the heliosphere distorted from axial symmetry by the ISMF.