The long-anticipated encounter by Voyager 2 (V2) of the region between the heliosphere and the very local interstellar medium (VLISM) occurred toward the end of 2018. Here, we report measurements of energetic (>28 keV) charged particles on V2 from the interface region between the heliosheath, dominated by heated solar wind plasma, and the VLISM, expected to contain cold non-solar plasma and the Galactic magnetic field. The number of particles of solar origin began a gradual decrease on 7 August 2018 (118.2 au), while those of Galactic origin (Galactic cosmic rays) increased ~20% in number over a period of a few weeks. An abrupt change occurred on 5 November when V2 was located at 119 au, with a decrease in the number of particles at energies of >28 keV and a corresponding increase in the number of Galactic cosmic rays of energy E > 213 MeV. This signature of the transition to the VLISM resembles, but is very different from, that observed on Voyager 1 at ~121.6 au, associated with the putative crossing of the heliopause some six years earlier.

Voyager 2（V2）长期以来一直期待着太阳球和非常局域星际介质（VLISM）之间的区域相遇，发生于2018年底。在这里，我们报告了对V2上高能（> 28 keV）带电粒子的测量位于被热的太阳风等离子体支配的太阳鞘与VLISM之间的界面区域，有望包含冷的非太阳能等离子体和银河磁场。太阳起源的粒子数量于2018年8月7日（118.2 au）开始逐渐减少，而银河起源的粒子（银河系宇宙射线）在几周内增加了约20％。当V2位于119 au时，在11月5日发生了突然的变化，能量> 28 keV的粒子数量减少了，银河宇宙射线的能量数量也相应增加了E  > 213 MeV。向VLISM过渡的这种特征与旅行者1号在〜121.6 au上观察到的特征相似，但非常不同，这与六年前推定的更年期有关。