Application of a Magnetic-field-induced Transition in Fe x to Solar and Stellar Coronal Magnetic Field Measurements

Abstract

Magnetic fields play a key role in driving a broad range of dynamic phenomena in the atmospheres of the Sun and other stars. Routine and accurate measurements of the magnetic field at all atmospheric layers are of critical importance to understand these magnetic activities but in the solar and stellar coronae they are a challenge. It was recently proposed that the magnetic-field-induced transition (MIT) in Fe~{\sc{x}} can be used to measure the weak coronal magnetic fields. In this review, we present an overview of recent progresses in the application of this method in astrophysics. We start by introducing the theory underlying the MIT method and reviewing the existing atomic data critical for the spectral modeling of Fe~{\sc{x}} lines. We also discuss the laboratory measurements that verify the potential capability of the MIT technique as a probe for diagnosing the plasma magnetic fields. We then continue by investigating the suitability and accuracy of solar and stellar coronal magnetic field measurements based on the MIT method through forward modeling. Furthermore, we discuss application of the MIT method to existing spectroscopic observations taken by the Extreme-ultraviolet Imaging Spectrometer onboard \textit{Hinode}. This novel technique provides a possible solution for routine magnetic field measurements of the solar and stellar coronae but still requires further efforts to achieve accurate measurements. Finally, the challenges and prospects for future research on this topic are discussed.

Global Coronal Plasma Diagnostics Based on Multislit Extreme-ultraviolet Spectroscopy

“…In the current work, we have presented a series of plasma diagnostics but excluded the diagnostic of the magnetic field strength. The phenomenon of magnetic-field-induced transition has been demonstrated to have the potential in measurements of the coronal magnetic field strength (Li et al 2015(Li et al , 2016Chen et al 2021;Martínez-Sykora et al 2022;Chen et al 2023). In the future, we may also involve the application of this novel method with a different EUV wavelength band to derive a global map of the coronal magnetic field.…”

Formation of Fan-spine Magnetic Topology through Flux Emergence and Subsequent Jet Production

“…The magnetic field plays a pivotal role in driving solar activity, yet the routine measurement of the coronal magnetic field continues to be a significant challenge (e.g., Yang et al 2020aYang et al , 2020bChen et al 2023). In this study, to characterize the 3D magnetic field of the fan-spine system, we chose the line-of-sight (LOS) HMI magnetogram as the bottom boundary for the local potential field extrapolation with a code provided by SolarSoftWare.…”

SISA: The First Extreme-Ultraviolet Solar Integral Field Spectrograph Using Slicers

“…The solar coronal magnetic field can be measured via the recently identified Fe X 184.54 /257.26 Å line intensity ratio [see, e.g. [67][68][69]. While the former line is an allowed transition, the latter, Fe X 257.26 Å, is a blend of several intercombination transitions.…”