Related papers: Element Abundances: A New Diagnostic for the Solar…
We compare element and isotopic fractionations measured in solar wind samples collected by NASA's Genesis mission with those predicted from models incorporating both the ponderomotive force in the chromosphere and conservation of the first…
Data obtained from Parker Solar Probe (PSP) since 2021 April have shown the first in situ observation of the solar corona, where the solar wind is formed and accelerated. Here we investigate the alpha-proton differential flow and its…
We investigate the propagation of Alfv\'en waves in the solar chromosphere, distinguishing between upward and downward propagating waves. We find clear evidence for the reflection of waves in the chromosphere and differences in propagation…
The discovery of ubiquitous low-frequency (3-5mHz) Alfvenic waves in the solar chromosphere (with Hinode/SOT), and corona (with CoMP and the Solar Dynamics Observatory, SDO) has provided some insight into the non-thermal energy content of…
Solar photospheric abundances and CI-chondrite compositions are reviewed and updated to obtain representative solar system abundances of the elements and their isotopes. The new photospheric abundances obtained here lead to higher solar…
We report X-ray spectroscopic results for four giant solar flares occurred on 2005 September 7 (X17.0), 2005 September 8 (X5.4), 2005 September 9 (X6.2), and 2006 December 5 (X9.0), obtained from Earth albedo data with the X-ray imaging…
The exploration of the inner heliosphere by Parker Solar Probe has revealed a highly structured solar wind with ubiquitous deflections from the Parker spiral, known as switchbacks. Interchange reconnection (IR) may play an important role in…
Using a classification scheme for solar wind type based on the heliocentric distance of the observation, we look at near perihelion observations from Parker Solar Probe Encounters Four to Fourteen to study the sources of the slow…
Recent studies have shown that the elemental abundances in the Sun are anomalous when compared to most (about 85%) nearby solar twin stars. Compared to its twins, the Sun exhibits a deficiency of refractory elements (those with condensation…
Although the enhancements in the alpha-proton ratio in the solar wind (expressed as $A_{He} = N_a/N_p*100$) in the Interplanetary Coronal Mass Ejections (ICMEs) have been studied in the past, $A_{He}$ enhancements at the stream interface…
We revisit a multi-spacecraft study of the element abundances of solar energetic particles (SEPs) in the 23 January 2012 event, where the power-law pattern of enhancements versus the mass-to-charge ratio A/Q for the elements C through Fe…
High-resolution spectropolarimetry has opened new avenues for understanding how chromospheric waves shape coronal plasma composition. All modeling efforts so far highlight wave activity and, in particular, the ponderomotive force associated…
The origination and generation mechanisms of small magnetic flux ropes (SFRs), which are important structures in solar wind, are not clearly known. In present study, 1993 SFRs immersed in coronal holes, active regions, and quiet Sun solar…
$PSP$ and $SolO$ data are utilized to investigate magnetic field intermittency in the solar wind (SW). Small-scale intermittency $(20-100d_{i})$ is observed to radially strengthen when methods relying on higher-order moments are considered…
We have studied the element abundances and energy spectra of the small "He-poor" impulsive solar energetic-particle (SEP) events, comparing them with other impulsive SEP events with more-normal abundances of He. He-poor events can have…
The calcium abundance in flare plasmas is estimated using X-ray spectra from the Solar Maximum Mission Bent Crystal Spectrometer (BCS) during the decays of 194 flares (GOES classifications from B6.4 to X13) occurring between 1980 and 1989.…
During Parker Solar Probe (Parker) Encounter 15 (E15), we observe an 18-hour period of near subsonic ($\mathrm{M_S \sim}$ 1) and sub-Alfv\'enic (SA), $\mathrm{M_A}$ <<< 1, slow speed solar wind from 22 to 15.6 R$_\odot$. As the most extreme…
Hydrogen has been almost completely ignored in studies of the abundance patterns of the chemical elements in solar energetic particles (SEPs). We seek to find impulsive events where H fits these abundance patterns and document the events…
The steep power-law dependence of element abundance enhancements on the mass-to-charge ratios [A/Q] of the ions in impulsive solar energetic-particle (SEP) events causes these enhancements to reflect the temperature-dependent pattern of Q…
Evidence for two different physical mechanisms for acceleration of solar energetic particles (SEPs) arose 50 years ago with radio observations of type III bursts, produced by outward streaming electrons, and type II bursts from coronal and…