SEP environment in the inner heliosphere from Solar Orbiter and Parker Solar Probe

TL;DR

This paper reviews recent observations of energetic particles in the inner heliosphere from Solar Orbiter and Parker Solar Probe, focusing on their acceleration, transport, and diverse sources within the solar wind environment.

Contribution

It provides new insights into particle acceleration and transport processes in the inner heliosphere based on recent spacecraft data.

Findings

Identification of multiple sources of energetic particles.

Observation of particle acceleration near the Sun and at shocks.

Insights into the composition and behavior of anomalous cosmic rays.

Abstract

The Sun drives a supersonic wind which inflates a giant plasma bubble in our very local interstellar neighborhood, the heliosphere. It is bathed in an extremely variable background of energetic ions and electrons which originate from a number of sources. Solar energetic particles (SEPs) are accelerated in the vicinity of the Sun, whereas shocks driven by solar disturbances are observed to accelerate energetic storm particles (ESPs). Moreover, a dilute population with a distinct composition forms the anomalous cosmic rays (ACRs) which are of a mixed interstellar-heliospheric origin. Particles are also accelerated at planetary bow shocks. We will present recent observations of energetic particles by Solar Orbiter and Parker Solar Probe, as well as other spacecraft that allow us to study the acceleration and transport of energetic particles at multiple locations in the inner heliosphere.