日球边界条件：星际和原位数据约束下的光电离模型
The Boundary Conditions of the Heliosphere: Photoionization Models Constrained by Interstellar and In Situ Data
摘要：
日球层的边界条件是由流入的星际物质的电离、密度和成分决定的。在日球层约束本地星际云（LIC）的性质需要辐射转移电离模型。我们使用观测到的恒星FUV和EUV辐射和漫射软X射线背景模拟背景星际辐射场。我们还模拟了从LIC和热的局部气泡（LB）等离子体之间的边界的发射，假设云蒸发，因为热传导。我们创建一个网格的模型，覆盖一个合理的范围内的LIC和LB属性，并使用建模的辐射场作为输入的辐射转移/热平衡计算使用多云代码。来自He^O、拾取离子和日球层中异常宇宙射线的原位观测数据以及朝向H2O CMa的吸收线测量被用来约束输入参数。一个有限的范围内的假设LIC HI柱密度和LB等离子体温度产生的模型，匹配所有的观测约束。对N（HI）和T_h的限制相对较弱，而对太阳LIC中H^O和电子密度的限制则较窄，n（H^0）= 0.19 - 0.20 cm^-3，n（e）= 0.07 +/- 0.01 cm^-3。导出的丰度大多是典型的低密度气体，与太阳下的Mg，Si和Fe，可能是太阳下的O和N，以及太阳附近的S;但是C是太阳上的。太阳上的星际气体温度较高，密度较低，部分电离，n（H）= 0.23 - 0.27 cm^-3，T = 6300 K，X（H^+）~ 0.2，X（He^+）~ 0.4。这些结果似乎是鲁棒的，因为可接受的模型被发现用于基本上不同的输入辐射场。我们的研究结果有利于LIC组成的参考太阳丰度的低值。
英文摘要：
The boundary conditions of the heliosphere are set by the ionization, density and composition of inflowing interstellar matter. Constraining the properties of the Local Interstellar Cloud (LIC) at the heliosphere requires radiative transfer ionization models. We model the background interstellar radiation field using observed stellar FUV and EUV emission and the diffuse soft X-ray background. We also model the emission from the boundary between the LIC and the hot Local Bubble (LB) plasma, assuming that the cloud is evaporating because of thermal conduction. We create a grid of models covering a plausible range of LIC and LB properties, and use the modeled radiation field as input to radiative transfer/thermal equilibrium calculations using the Cloudy code. Data from in situ observations of He^O, pickup ions and anomalous cosmic rays in the heliosphere, and absorption line measurements towards epsilon CMa were used to constrain the input parameters. A restricted range of assumed LIC HI column densities and LB plasma temperatures produce models that match all the observational constraints. The relative weakness of the constraints on N(HI) and T_h contrast with the narrow limits predicted for the H^O and electron density in the LIC at the Sun, n(H^0) = 0.19 - 0.20 cm^-3, and n(e) = 0.07 +/- 0.01 cm^-3. Derived abundances are mostly typical for low density gas, with sub-solar Mg, Si and Fe, possibly subsolar O and N, and S about solar; however C is supersolar. The interstellar gas at the Sun is warm, low density, and partially ionized, with n(H) = 0.23 - 0.27 cm^-3, T = 6300 K, X(H^+) ~ 0.2, and X(He^+) ~ 0.4. These results appear to be robust since acceptable models are found for substantially different input radiation fields. Our results favor low values for the reference solar abundances for the LIC composition.
机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。
