Related papers: Ion Traps at the Sun: Implications for Elemental F…
Cold ions trapped in the vicinity of conductive surfaces experience heating of their oscillatory motion. Typically, the rate of this heating is orders of magnitude larger than expected from electric field fluctuations due to thermal motion…
We present coordinated coronal observations of the August 21, 2017 total solar eclipse with the Airborne Infrared Spectrometer (AIR-Spec) and the Extreme-ultraviolet Imaging Spectrometer (EIS). These instruments provide an unprecedented…
X-ray and EUV observations are an important diagnostic of various plasma parameters of the solar atmosphere during solar flares. Soft X-ray and EUV observations often show coronal sources near the top of flaring loops, while hard X-ray…
We consider the generation of electric currents in the solar chromosphere where the ionization level is typically low. We show that ambient electrons become magnetized even for weak magnetic fields (30 G); that is, their gyrofrequency…
The EUI instrument on the Solar Orbiter spacecraft has obtained the most stable, high-resolution images of the solar corona from its orbit with a perihelion near 0.4 AU. A sequence of 360 images obtained at 17.1 nm, between 25-Oct-2022…
Plasma composition measurements are a vital tool for the success of current and future solar missions, but density and temperature insensitive spectroscopic diagnostic ratios are sparse, and their underlying accuracy in determining the…
Intending to solve the decade old problem of solar opacity, we report substantial photoabsorption uncertainty due to the effect of ion-ion correlations. By performing detailed opacity calculations of the solar mixture, we find that taking…
Heavy ions are markers of the physical processes responsible for the density and temperature distribution throughout the fine scale magnetic structures that define the shape of the solar corona. One of their properties, whose empirical…
EUV images of Comet Lovejoy (C/2011 W3) from the AIA show striations related to the magnetic field structure in both open and closed magnetic regions. The brightness contrast implies coronal density contrasts of at least a factor of 6…
We present a detailed analysis of oxygen ion velocity distributions in the extended solar corona, based on observations made with the Ultraviolet Coronagraph Spectrometer (UVCS) on the SOHO spacecraft. Polar coronal holes at solar minimum…
We have reanalyzed SUMER observations of a parcel of coronal gas using new collisional ionization equilibrium (CIE) calculations. These improved CIE fractional abundances were calculated using state-of-the-art electron-ion recombination…
The quiet solar corona consists of myriads of loop-like features, with magnetic fields originating from network and internetwork regions on the solar surface. The continuous interaction between these different magnetic patches leads to…
We present a further investigation into the increased ionization observed in element charge states in the fast solar wind compared to its coronal hole source regions. Once ions begin to be perpendicularly heated by ion cyclotron waves and…
We investigate a global extreme-ultraviolet (EUV) wave associated with a coronal mass ejection (CME)-driven shock on 2017 September 10. The EUV wave is transmitted by north- and south-polar coronal holes (CHs), which is observed by the…
Plasma composition in the solar corona commonly differs from that of the photosphere, with the enhancement of low--first-ionization-potential (FIP) elements referred to as the FIP effect. This phenomenon provides important diagnostics of…
X-Ray and Ultraviolet (UV) observations of the outer solar atmosphere have been used for many decades to measure the fundamental parameters of the solar plasma. This review focuses on the optically thin emission from the solar atmosphere,…
Context: Acceleration in coronal mass ejection driven shocks is currently considered the primary source of large solar energetic particle events. Aims: The solar wind, which feeds shock-accelerated particles, includes numerous ion…
Small 3He-rich solar energetic particle (SEP) events with their anomalous abundances, markedly different from solar system, provide evidence for a unique acceleration mechanism that operates routinely near solar active regions. Although the…
In this letter we have made a comparative study of degradation of solar EUV radiation and EUV-generated photoelectrons in the inner comae of comets having different gas production rates, Q, with values 1x10^28, 7x10^29, 1x10^31, and 1x10^32…
We analyse the coronal elemental abundances during a small flare using Hinode/EIS observations. Compared to the pre-flare elemental abundances, we observed a strong increase in coronal abundance of Ca XIV 193.84 {\AA}, an emission line with…