X-ray Emissions from the Jovian System

TL;DR

The paper reviews the diverse X-ray emissions from Jupiter's system, highlighting their physical origins, recent observational advances, and future prospects with upcoming missions and instrumentation for understanding planetary and space plasma processes.

Contribution

It provides a comprehensive overview of Jupiter's X-ray sources, recent findings, and discusses future instrumentation and missions to enhance understanding of planetary X-ray emissions.

Findings

Jupiter's X-ray emissions originate from multiple processes including scattering, charge exchange, and bremsstrahlung.

Simultaneous X-ray and in-situ measurements link emissions to wave-particle interactions.

Future missions and advanced instrumentation will enable detailed mapping of elemental compositions and physical processes.

Abstract

The Jovian system is a treasure trove of X-ray sources: diverse and dynamic atmospheric and auroral emissions, diffuse radiation belt and Io torus emissions, and plasma-surface interactions with Jupiter's moons. The system is a rich natural laboratory for astronomical X-rays with each region showcasing its own X-ray production processes: scattering and fluorescence of solar corona emissions; charge exchange emissions from energetic ions; Inverse-Compton, thermal and non-thermal bremsstrahlung emissions from relativistic electrons; and fingerprint fluorescence lines indicative of elemental composition and the potential for life on the Galilean satellites. For the high energy astrophysics domain, perhaps Jupiter's greatest attribute is the opportunity to connect observed X-ray emissions with in-situ plasma and magnetic field measurements of the precise physical processes that lead to them - irreplaceable ground truths for systems that cannot be visited in-situ. Such simultaneous studies have revealed that Jupiter's spectacular soft X-ray flares and pulsations are produced by wave-particle interactions, while the bremsstrahlung aurorae vary with magnetodisk reconnection and dipolarisation. While many remote signatures remain to be linked with their source processes, the future is bright, with synergistic Chandra, NuSTAR, XMM-Newton and Juno in-situ measurements continuing to provide revolutionary insights in the coming years, while JUICE and Europa missions with ATHENA and possibly Lynx will enable a new legacy. However, to truly characterise some emissions (e.g. mapping Galilean satellite elemental composition) in-situ X-ray instrumentation is a necessity. Recent advances enable compact, lightweight, X-ray instrumentation perfectly suited for Jupiter science. The chapter closes by reviewing feasible, low-risk concepts that would paradigm-shift our understanding of the system.