Beginning on 2020 June 19, at a heliocentric distance of 124.2 au, the Voyager 2 Plasma Wave Science instrument began to observe radio emissions followed by electron plasma oscillations in its 3.11 kHz spectrum analyzer channel. Plasma oscillations at this frequency imply an electron density in the range of 0.12 cm −3 ± 15%, although some response in the 1.78 kHz channel near the peak of the plasma oscillations suggest a density of 0.087 cm −3 ± 8%. Shortly after Voyager 2 crossed the heliopause, in late 2019 January, the Voyager 2 Plasma Wave Science instrument detected plasma oscillations in its 1.78 kHz channel giving an electron density of 0.039 cm −3 ± 15%. While the Voyager spectrum analyzer affords relatively poor spectral resolution, the recent observation of plasma oscillations in the 3.11 kHz channel provides definitive evidence of a radial density gradient in the very local interstellar medium (VLISM), just beyond the heliopause with a ma...

中文翻译：

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Voyager 2在非常局域星际介质中观测到的径向密度梯度

从2020年6月19日开始，Voyager 2等离子体波科学仪器以124.2 au的日心中心距离开始观察无线电发射，随后在其3.11 kHz频谱分析仪通道中观察到电子等离子体振荡。在此频率下的等离子体振荡意味着电子密度在0.12 cm -3±15％的范围内，尽管在靠近等离子体振荡峰值的1.78 kHz通道中有一些响应表明，密度为0.087 cm -3±8％。Voyager 2穿越直升机停机时间后不久，于2019年1月下旬，Voyager 2等离子波科学仪器在其1.78 kHz通道中检测到等离子体振荡，电子密度为0.039 cm -3±15％。虽然Voyager频谱分析仪提供的频谱分辨率相对较差，但最近观察到3中的等离子体振荡。