A5089907313- Solar and Space Plasma Dynamics
- Gamma-ray bursts and supernovae
- Astro and Planetary Science
- Ionosphere and magnetosphere dynamics
- Stellar, planetary, and galactic studies
- Calibration and Measurement Techniques
- Spacecraft Design and Technology
- Astrophysical Phenomena and Observations
- Particle Detector Development and Performance
- Radiation Therapy and Dosimetry
- Planetary Science and Exploration
- Spacecraft and Cryogenic Technologies
- Rocket and propulsion systems research
- Radiative Heat Transfer Studies
- Astrophysics and Cosmic Phenomena
- Nuclear Physics and Applications
- Geomagnetism and Paleomagnetism Studies
- Advanced Semiconductor Detectors and Materials
- Advanced X-ray Imaging Techniques
- Earthquake Detection and Analysis
- Adaptive optics and wavefront sensing
- Radiation Effects in Electronics
- Optical Wireless Communication Technologies
- Advanced X-ray and CT Imaging
- Space exploration and regulation
Johns Hopkins University Applied Physics Laboratory
2021-2024
Johns Hopkins University
2022-2023
University of Minnesota
2017-2022
Twin Cities Orthopedics
2017-2021
University of Minnesota System
2016-2019
Universidad Veritas
2015
The Focusing Optics X-ray Solar Imager (FOXSI) is, in its initial form, a sounding rocket experiment designed to apply the technique of focusing hard (HXR) optics study fundamental questions about high-energy Sun. HXRs arise via bremsstrahlung from energetic electrons and hot plasma produced solar flares thus are one most direct diagnostics are-accelerated impulsive heating corona. Previous missions have always been limited sensitivity dynamic range by use indirect (Fourier) imaging due lack...
In this paper we present the differential emission measures (DEMs) of two sub-A class microflares observed in hard X-rays (HXRs) by FOXSI-2 sounding rocket experiment, on 2014 December 11. The second FOXSI (Focusing Optics X-ray Solar Imager) flight was coordinated with instruments Hinode/XRT and SDO/AIA, which provided observations soft (SXR) Extreme Ultraviolet (EUV). This unique dataset offers an unprecedented temperature coverage useful for characterizing plasma distribution microflares....
Solar flares are explosive releases of magnetic energy. Hard X-ray (HXR) flare emission originates from both hot (millions Kelvin) plasma and nonthermal accelerated particles, giving insight into energy release. The Nuclear Spectroscopic Telescope ARray (NuSTAR) utilizes direct-focusing optics to attain much higher sensitivity in the HXR range than that previous indirect imagers. This paper presents 11 NuSTAR microflares two active regions (AR 12671 on 2017 August 21 AR 12712 2018 May 29)....
Mesoscale dynamics are a fundamental process in space physics, but fall within an observational gap of current and planned missions. Particularly the solar wind, measurements at mesoscales (100s R E to few degrees heliographic longitude 1 au) crucial for understanding connection between corona observer anywhere heliosphere. may also be key revealing currently unresolved physics regulating particle acceleration transport, magnetic field topology, causes variability composition wind plasma....
Abstract High-energy neutral solar radiation in the form of γ -rays and neutrons is produced as secondary products flares. The characteristics this emission can provide key information regarding energization charged particles, particularly when primary particles remain trapped corona. Integrated Science Investigation Sun (IS⊙IS) suite on Parker Solar Probe composed instruments primarily intended to measure energetic particles. However, High Energy Telescope (HET) IS⊙IS was also designed with...
Much evidence suggests that the solar corona is heated impulsively, meaning nanoflares may be ubiquitous in quiet and active regions (ARs). Hard X-ray (HXR) observations with unprecedented sensitivity $>$3~keV are now enabled by focusing instruments. We analyzed data from \textit{Focusing Optics Solar Imager (FOXSI)} rocket \textit{Nuclear Spectroscopic Telescope Array (NuSTAR)} spacecraft to constrain properties of AR simulated EBTEL field-line-averaged hydrodynamics code. generated model...
Abstract We study the evolution of solar eruptive events by investigating temporal relationships among magnetic reconnection, flare energy release, and acceleration coronal mass ejections (CMEs). Leveraging optimal viewing geometry Solar TErrestrial RElations Observatory (STEREO) relative to Dynamics (SDO) Reuven Ramaty High-Energy Spectroscopic Imager (RHESSI) during 2010–2013, we identify 12 with sufficient spatial coverage for a detailed examination. STEREO SDO data are used measure CME...
Whitepaper #333 in the Decadal Survey for Solar and Space Physics (Heliophysics) 2024-2033. Main topics: space weather applications; basic research. Additional research/operations/research loop; research/applications/operations pipeline; […]
Abstract Hard X-ray (HXR) observations are crucial for understanding the initiation and evolution of solar eruptive events, as they provide a key signature flare-accelerated electrons heated plasma. The potential high-cadence HXR imaging deciphering erupting structure, however, has not received adequate attention in an era extreme ultraviolet (EUV) abundance. An event on 2022 September 5 observed far side by both Parker Solar Probe Orbiter provides opportunity to showcase power absence EUV...
Context. Solar nanoflares are small impulsive events releasing magnetic energy in the corona. If follow same physics as their larger counterparts, they should emit hard X-rays (HXRs) but with a rather faint intensity. A copious and continuous presence of would result sustained HXR emission. These could deliver enormous amounts into solar corona, possibly accounting for its high temperatures. To date, there has not been any direct observation such persistent HXRs from quiescent Sun. However,...
The FOXSI-4 sounding rocket will fly a significantly upgraded instrument in NASA's first solar are campaign. It deploy direct X-ray focusing optics which have revolutionized our understanding of astrophysical phenomena. For example, they allowed NuSTAR to provide imaging and IXPE (scheduled for launch 2021) polarization observations with detectors higher photon rate capability greater sensitivity than their predecessors. FOXSI is the dedicated mission using this method has demonstrated high...
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The Focusing Optics X-ray Solar Imager (FOXSI) sounding rocket experiment conducts direct imaging and spectral observation of the Sun in hard X-rays, energy range 4 to 20 keV. These high-sensitivity observations are used study particle acceleration coronal heating. FOXSI is designed with seven grazing incidence optics modules that focus X-rays onto focal plane detectors kept at a 2m distance. FOXSI-1 was flown Double-sided Si Strip Detectors (DSSD), two them were replaced CdTe for FOXSI-2....
We study the structure and dynamics of extreme flaring events on young stellar objects (YSOs) observed in hard X-rays by Nuclear Spectroscopic Telescope Array (NuSTAR). During 2015 2016, NuSTAR made three observations star-forming region ρ Ophiuchi, each with an exposure ~50 ks. offers unprecedented sensitivity above ~7 keV, making this data set first its kind. Through improved coverage X-rays, it is finally possible to directly measure high-energy thermal continuum for hot plasmas...
The Focusing Optics X-ray Solar Imager (FOXSI) sounding rocket experiment demonstrates the technique of focusing hard (HXR) optics for study fundamental questions about high-energy Sun. HXRs provide one most direct diagnostics accelerated electrons and impulsive heating solar corona. Previous missions have been limited in sensitivity dynamic range by use indirect imaging, but technological advances now make accessible HXR regime, FOXSI optimizes telescopes unique scientific requirements has...
Imaging X-rays by direct focusing offers greater sensitivity and a higher dynamic range compared to techniques based on indirect imaging. The Focusing Optics X-ray Solar Imager (FOXSI) is sounding rocket payload that uses seven sets of nested Wolter-I figured mirrors observe the Sun in hard through focusing. Characterizing performance these optics critical optimize their understand resulting data. In this paper, we present ray-tracing simulation created developed study mirrors. We validated...
In this white paper, we demonstrate the scientific value of interdisciplinary research on highenergy solar and stellar activity advocate for programmatic implementation that facilitates encourages collaboration.Solar eruptive events are most energetic in our system; they provide insight into energy release mechanisms corona a key source particles space weather.This also holds true context; moreover, released by domain can be orders magnitude greater than Sun.Interdisciplinary solar/stellar...
In high energy solar astrophysics, imaging hard X-rays by direct focusing offers higher dynamic range and greater sensitivity compared to past techniques that used indirect imaging. The Focusing Optics X-ray Solar Imager (FOXSI) is a sounding rocket payload uses seven sets of nested Wolter-I figured mirrors together with high-sensitivity semiconductor detectors observe the Sun in through focusing. FOXSI has successfully flown twice funded fly third time summer 2018. geometry consists two...
Intermediate-frequency-peaked BL Lacertae objects (IBLs) are a class of blazars characterized by spectral energy distribution (SED) with lower-energy synchrotron peak than the majority extragalactic sources detected ground-based imaging atmospheric Cherenkov telescopes (IACTs). Consequently, gamma-ray flux falls outside very-high-energy regime (VHE, >100 GeV) covered IACTs such as VERITAS, making IBLs difficult to detect except during infrequent episodes elevated flux. However, study...
Understanding the nature of energetic particles in solar atmosphere is one most important outstanding problems heliophysics.Flare-accelerated compose a huge fraction flare energy budget; they have large influences on how events develop; are an source high-energy found heliosphere; and single corollary to other areas astrophysics.Despite importance this area study, topic has past decade received only small resources necessary for full investigation.For example, NASA selected no new...
Our current theoretical and observational understanding suggests that critical properties of the solar wind Coronal Mass Ejections (CMEs) are imparted within 10 Rs, particularly below 4 Rs.This seemingly narrow spatial region encompasses transition coronal plasma processes through entire range physical regimes from fluid to kinetic, primarily closed open magnetic field structures.From a physics perspective, therefore, it is more appropriate refer this as Critical Transition Region (CCTR)...