Voyager 1 in the foreshock, termination shock, and heliosheath
Voyager 1 in the foreshock, termination shock, and heliosheath
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DOI：
10.1126/science.1117569
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发表时间：
2005-09-23
期刊：
影响因子：
56.9
通讯作者：
Lanzerotti, LJ
中科院分区：
文献类型：
--
作者：
Decker, RB;Krimigis, SM;Lanzerotti, LJ
旅行者1号（V1）于2002年7月开始测量来自日球层终端激波（TS）的前驱高能离子和电子。在随后的2.5年里，随着V1深入TS的高能粒子前震，平均粒子强度上升。在整个2004年，V1观测到的离子强度甚至更大，从每核子40千电子伏特（keV）到>= 50兆电子伏特，从>到>= 350千电子伏特。2004年第350天（2004/350），V1观测到离子和电子的强度峰值，随后在最低能量处持续增加10倍，在较高能量处增加较小，比自1982年V1达到15个天文单位以来的任何强度都要大。估算的太阳风径向流速度为正。（向外）从2004/352年到2005/018年，大约为每秒+100公里（km s(-1)），这时径向流动主要是负的（向太阳），在类似于-50和0 km s（-1）之间波动，直到大约005/110年；然后它们变得更加积极，最近的值（2005/179）类似于+50 km s（-1）。后激波时期平均的高能质子谱显然是由强烈加热的星际拾取离子主导的。我们将这些观测解释为TS在2004/351年（在跟踪间隙期间）以94.0天文单位的速度穿过V1的证据，显然是由于激波向内移动以响应太阳风冲击压的下降，并且V1至少在2005年中期之前一直留在日鞘中。
Voyager 1 (V1) began measuring precursor energetic ions and electrons from the heliospheric termination shock (TS) in July 2002. During the ensuing 2.5 years, average particle intensities rose as V1 penetrated deeper into the energetic particle foreshock of the TS. Throughout 2004, V1 observed even larger, fluctuating intensities of ions from 40 kiloetectron volts (keV) to >= 50 megaelectron volts per nucleon and of electrons from >26 keV to >= 350 keV. On day 350 of 2004 (2004/350), V1 observed an intensity spike of ions and electrons that was followed by a sustained factor of 10 increase at the lowest energies and lesser increases at higher energies, larger than any intensities since V1 was at 15 astronomical units in 1982. The estimated solar wind radial flow speed was positive.(outward) at similar to +100 kilometers per second (km s(-1)) from 2004/352 until 2005/018, when the radial flows became predominantly negative (sunward) and fluctuated between similar to -50 and 0 km s(-1) until about 005/110; they then became more positive, with recent values (2005/179) of similar to +50 km s(-1). The energetic proton spectrum averaged over the postshock period is apparently dominated by strongly heated interstellar pickup ions. We interpret these observations as evidence that V1 was crossed by the TS on 2004/351 (during a tracking gap) at 94.0 astronomical units, evidently as the shock was moving radially inward in response to decreasing solar wind ram pressure, and that V1 has remained in the heliosheath until at least mid-2005.