The Focusing Optics X-ray Solar Imager (FOXSI)

TL;DR

FOXSI is a novel hard X-ray telescope that provides rapid, high-resolution imaging spectroscopy of solar flares, enabling detailed study of energy release and particle acceleration in the solar corona.

Contribution

It introduces a new imaging spectrometer with two orders of magnitude faster data acquisition, allowing unprecedented insights into solar flare dynamics and energetic processes.

Findings

Enhanced temporal resolution in solar flare imaging

Simultaneous observation of accelerated electrons and hot plasma

Full characterization of energy, space, and time evolution of solar eruptions

Abstract

FOXSI is a direct-imaging, hard X-ray (HXR) telescope optimized for solar flare observations. It detects hot plasma and energetic electrons in and near energy release sites in the solar corona via bremsstrahlung emission, measuring both spatial structure and particle energy distributions. It provides two orders of magnitude faster imaging spectroscopy than previously available, probing physically relevant timescales (<1s) never before accessible to address fundamental questions of energy release and efficient particle acceleration that have importance far beyond their solar application (e.g., planetary magnetospheres, flaring stars, accretion disks). FOXSI measures not only the bright chromospheric X-ray emission where electrons lose most of their energy, but also simultaneous emission from electrons as they are accelerated in the corona and propagate along magnetic field lines. FOXSI detects emission from high in the tenuous corona, where previous instruments have been blinded by nearby bright features and will fully characterizes the accelerated electrons and hottest plasmas as they evolve in energy, space, and time to solve the mystery of how impulsive energy release leads to solar eruptions, the primary drivers of space weather at Earth, and how those eruptions are energized and evolve.