SmallSat Solar Axion and Activity X-ray Imager (SSAXI)

TL;DR

SSAXI is a proposed SmallSat mission designed to detect solar axions and monitor solar X-ray activity, utilizing advanced X-ray optics and sensors to distinguish axion signals from solar background over a broad energy range.

Contribution

The paper introduces a novel SmallSat mission concept employing lightweight X-ray optics and CMOS sensors for solar axion detection and solar activity monitoring.

Findings

Design of SSAXI with wide energy range (0.5-6 keV) for axion detection.

High angular resolution (30 arcsec HPD) enables core imaging.

Large field of view (40 arcmin) covers entire solar disc.

Abstract

Axions are a promising dark matter candidate as well as a solution to the strong charge-parity (CP) problem in quantum chromodynamics (QCD). We describe a new mission concept for SmallSat Solar Axion and Activity X-ray Imager (SSAXI) to search for solar axions or axion-like particles (ALPs) and to monitor solar activity of the entire solar disc over a wide dynamic range. SSAXI aims to unambiguously identify X-rays converted from axions in the solar magnetic field along the line of sight to the solar core, effectively imaging the solar core. SSAXI also plans to establish a statistical database of X-ray activities from Active Regions, microflares, and Quiet Sun regions to understand the origin of the solar corona heating processes. SSAXI employs Miniature lightweight Wolter-I focusing X-ray optics (MiXO) and monolithic CMOS X-ray sensors in a compact package. The wide energy range (0.5 - 6 keV) of SSAXI can easily distinguish spectra of axion-converted X-rays from typical X-ray spectra of solar activities, while encompassing the prime energy band (3 - 4.5 keV) of axion-converted X-rays. The high angular resolution (30 arcsec HPD) and large field of view (40 arcmin) in SSAXI will easily resolve the enhanced X-ray flux over the 3 arcmin wide solar core while fully covering the X-ray activity over the entire solar disc. The fast readout in the inherently radiation tolerant CMOS X-ray sensors enables high resolution spectroscopy with a wide dynamic range in a broad range of operational temperatures. SSAXI will operate in a Sun-synchronous orbit for 1 yr preferably near a solar minimum to accumulate sufficient X-ray photon statistics.