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Main Authors: Gu, Chaoran, Berger, Lars, Heidrich-Meisner, Verena, Jentsch, Erik, Wimmer-Schweingruber, Robert F., Seimetz, Lars
Format: Preprint
Published: 2026
Subjects:
Online Access:https://arxiv.org/abs/2605.27096
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author Gu, Chaoran
Berger, Lars
Heidrich-Meisner, Verena
Jentsch, Erik
Wimmer-Schweingruber, Robert F.
Seimetz, Lars
author_facet Gu, Chaoran
Berger, Lars
Heidrich-Meisner, Verena
Jentsch, Erik
Wimmer-Schweingruber, Robert F.
Seimetz, Lars
contents Interstellar pickup ions originate from the neutral interstellar medium, are ionized in the heliosphere, and picked up by the solar wind. They initially form a torus-shaped velocity distribution function, which is generally believed to be transformed rapidly into an isotropic shell distribution by pitch-angle scattering. With the SupraThermal Electron Proton onboard Solar Orbiter we observe clear torus-shaped velocity distribution functions at an unprecedented one minute resolution. While these tori are variable on a time scale of one minute, they remain stable for over ten hours without signs of significant scattering. We conclude that they are populated by a huge fraction of the expected total number of pick-up ions injected in the past of the same solar wind stream.
format Preprint
id arxiv_https___arxiv_org_abs_2605_27096
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Observations of stable pickup He$^+$ tori in a magnetic flux rope at 0.85 au
Gu, Chaoran
Berger, Lars
Heidrich-Meisner, Verena
Jentsch, Erik
Wimmer-Schweingruber, Robert F.
Seimetz, Lars
Solar and Stellar Astrophysics
Interstellar pickup ions originate from the neutral interstellar medium, are ionized in the heliosphere, and picked up by the solar wind. They initially form a torus-shaped velocity distribution function, which is generally believed to be transformed rapidly into an isotropic shell distribution by pitch-angle scattering. With the SupraThermal Electron Proton onboard Solar Orbiter we observe clear torus-shaped velocity distribution functions at an unprecedented one minute resolution. While these tori are variable on a time scale of one minute, they remain stable for over ten hours without signs of significant scattering. We conclude that they are populated by a huge fraction of the expected total number of pick-up ions injected in the past of the same solar wind stream.
title Observations of stable pickup He$^+$ tori in a magnetic flux rope at 0.85 au
topic Solar and Stellar Astrophysics
url https://arxiv.org/abs/2605.27096