Observations of Cross Scale Energy Transfer in the Inner Heliosphere by Parker Solar Probe

TL;DR

This paper reviews Parker Solar Probe observations of turbulent energy transfer across scales in the inner heliosphere, enhancing understanding of solar wind turbulence and its evolution close to the sun.

Contribution

It provides a comprehensive analysis of PSP data on energy transfer in solar wind turbulence, highlighting new insights into multi-scale processes near the sun.

Findings

Observation of energy cascade from large to small scales

Identification of turbulence characteristics close to the sun

Open questions for future PSP investigations

Abstract

The solar wind, a continuous flow of plasma from the sun, not only shapes the near Earth space environment but also serves as a natural laboratory to study plasma turbulence in conditions that are not achievable in the lab. Starting with the Mariners, for more than five decades, multiple space missions have enabled in-depth studies of solar wind turbulence. Parker Solar Probe (PSP) was launched to explore the origins and evolution of the solar wind. With its state-of-the-art instrumentation and unprecedented close approaches to the sun, PSP is starting a new era of inner heliospheric exploration. In this review we discuss observations of turbulent energy flow across scales in the inner heliosphere as observed by PSP. After providing a quick theoretical overview and a quick recap of turbulence before PSP, we discuss in detail the observations of energy at various scales on its journey from the largest scales to the internal degrees of freedom of the plasma. We conclude with some open ended questions, many of which we hope that PSP will help answer.