Parker Solar Probe: Four Years of Discoveries at Solar Cycle Minimum

TL;DR

The Parker Solar Probe's first four years yielded groundbreaking insights into solar corona and wind physics, significantly advancing understanding of solar magnetic fields, plasma dynamics, and energetic particle acceleration during solar minimum conditions.

Contribution

This paper provides a comprehensive overview of scientific discoveries from the first four years of the Parker Solar Probe mission, highlighting advances beyond initial objectives.

Findings

Revealed detailed structure of the solar corona and magnetic fields.

Identified new mechanisms of solar wind acceleration.

Discovered processes responsible for energetic particle acceleration.

Abstract

Launched on 12 Aug. 2018, NASA's Parker Solar Probe had completed 13 of its scheduled 24 orbits around the Sun by Nov. 2022. The mission's primary science goal is to determine the structure and dynamics of the Sun's coronal magnetic field, understand how the solar corona and wind are heated and accelerated, and determine what processes accelerate energetic particles. Parker Solar Probe returned a treasure trove of science data that far exceeded quality, significance, and quantity expectations, leading to a significant number of discoveries reported in nearly 700 peer-reviewed publications. The first four years of the 7-year primary mission duration have been mostly during solar minimum conditions with few major solar events. Starting with orbit 8 (i.e., 28 Apr. 2021), Parker flew through the magnetically dominated corona, i.e., sub-Alfv\'enic solar wind, which is one of the mission's primary objectives. In this paper, we present an overview of the scientific advances made mainly during the first four years of the Parker Solar Probe mission, which go well beyond the three science objectives that are: (1) Trace the flow of energy that heats and accelerates the solar corona and solar wind; (2) Determine the structure and dynamics of the plasma and magnetic fields at the sources of the solar wind; and (3) Explore mechanisms that accelerate and transport energetic particles.