A5081001507- Solar and Space Plasma Dynamics
- Stellar, planetary, and galactic studies
- Gamma-ray bursts and supernovae
- Astro and Planetary Science
- Astrophysics and Cosmic Phenomena
- Atomic and Molecular Physics
- Ionosphere and magnetosphere dynamics
- Astrophysical Phenomena and Observations
- Astronomy and Astrophysical Research
- Laser-induced spectroscopy and plasma
- Astrophysics and Star Formation Studies
- X-ray Spectroscopy and Fluorescence Analysis
- Mass Spectrometry Techniques and Applications
- Pulsars and Gravitational Waves Research
- Laser-Plasma Interactions and Diagnostics
- Neutrino Physics Research
- Plasma Diagnostics and Applications
- Geomagnetism and Paleomagnetism Studies
- Atmospheric Ozone and Climate
- Gas Dynamics and Kinetic Theory
- Radioactive Decay and Measurement Techniques
- Magnetic confinement fusion research
- Particle accelerators and beam dynamics
- Astronomical Observations and Instrumentation
- Geophysics and Gravity Measurements
United States Naval Research Laboratory
2015-2024
United States Navy
2023
Naval Research Laboratory Space Science Division
2004-2020
The University of Tokyo
2019
Aoyama Gakuin University
2019
Saitama University
2019
Tohoku University
2019
K Lab (United States)
2003-2011
Trinity College Dublin
2009
Smithsonian Astrophysical Observatory
2005
We review our state of knowledge coronal element abundance anomalies in the Sun and stars. concentrate on first ionization potential (FIP) effect observed solar corona slow-speed wind, coronae solar-like dwarf stars, “inverse FIP” seen stars later spectral type; specifically M dwarfs. These effects relate to enhancement or depletion, respectively, with respect photospheric values elements FIP below about 10 eV. They are interpreted terms ponderomotive force due propagation and/or reflection...
We introduce a million second observation of the supernova remnant Cassiopeia A with Chandra X-Ray Observatory. The bipolar structure Si-rich ejecta (northeast jet and southwest counterpart) is clearly evident in new images, their chemical similarity confirmed by spectra. These are most likely due to jets as opposed cavities circumstellar medium, since we can reject simple models for latter. properties these Fe-rich will provide clues explosion Cas A.
We discuss models for coronal abundance anomalies observed in the coronae of sun and other late-type stars following a scenario first introduced by Schwadron, Fisk, & Zurbuchen interaction waves at loop footpoints with partially neutral gas. Instead considering wave heating ions this location, we explore effects on upper chromospheric plasma pondermotive forces. These can arise when upward-propagating from chromosphere transmit or reflect upon reaching chromosphere-corona boundary, are large...
We present a survey of the X-ray emitting ejecta in Cassiopeia A supernova remnant based on an extensive analysis over 6000 spectral regions extracted 2.5-10" angular scales using Chandra 1 Ms observation. interpret these results context hydrodynamical models for evolution remnant. The distributions fitted temperature and ionization age, implied mass coordinates, are highly peaked suggest that were subjected to multiple secondary shocks following reverse shock interaction with...
The distribution of elements produced in the inner-most layers a supernova explosion is key diagnostic for studying collapse massive stars. Here we present results 2.4 Ms \textit{NuSTAR} observing campaign aimed at remnant Cassiopeia A (Cas A). We perform spatially-resolved spectroscopic analyses $^{44}$Ti ejecta which use to determine Doppler shift and thus three-dimensional (3D) velocities ejecta. find an initial mass 1.54 $\pm$ 0.21 $\times 10^{-4}$ M$_{\odot}$ has day average momentum...
Abstract We present initial results from a James Webb Space Telescope (JWST) survey of the youngest Galactic core-collapse supernova remnant, Cassiopeia A (Cas A), made up NIRCam and MIRI imaging mosaics that map emission main shell, interior, surrounding circumstellar/interstellar material (CSM/ISM). also four exploratory positions Medium Resolution Spectrograph integral field unit spectroscopy sample ejecta, CSM, associated dust representative shocked unshocked regions. Surprising...
We review observational progress in the determination of element abundances solar corona, largely due to new capabilities offered by instrumentation on SOHO satellite. Many facets coronal abundance anomalies with respect photosphere are revealed. This includes results FIP (First Ionization Potential) Effect, whereby elements < 10 eV enriched corona a factor ~4 photosphere, and first evidence for gravitational settling heavy corona. Advances EUV x-ray astronomy have also yielded spectra...
The analysis of Balmer-dominated optical spectra from nonradiative (adiabatic) SNRs has shown that the ratio electron to proton temperature at blast wave is close unity vS ≲ 400 km s-1 but declines sharply down minimum value me/mp dictated by jump conditions shock speeds exceeding 2000 s-1. We propose a physical model for heating electrons and ions in non-cosmic-ray-dominated, strong shocks (vS > s-1) wherein are heated lower hybrid waves immediately ahead front. These arise naturally cosmic...
We present a detailed analysis of Chandra X-ray spectra from individual ejecta knots in the supernova remnant Cassiopeia A. The are fitted to give electron temperature and (single) ionization age. These quantities compared with predictions self similar hydrodynamic models incorporating time dependent radiation losses, Coulomb electron-ion equilibration behind reverse shock, for variety different density profiles described by uniform core power law envelope. find that close "jet" region NE,...
Reliably interpreting spectra from electron-ionized cosmic plasmas requires accurate ionization balance calculations for the plasma in question. However, much of atomic data needed these have not been generated using modern theoretical methods and are often highly suspect. This translates directly into reliability collisional equilibrium (CIE) calculations. We make use state-of-the-art dielectronic recombination (DR) rate coefficients hydrogenic through Na-like ions all elements He up to...
Using spectra obtained by the SUMER instrument on Solar and Heliospheric Observatory (SOHO) we have determined composition of bulk coronal plasma in vicinity solar surface over a polar hole an equatorial region. Our measurements show that although low first ionization potential (FIP) elements are enriched about factor 4 corona above quiet region, little or no enrichment exists north hole. These observations good agreement with Ulysses situ both fast speed slow winds.
We present initial results of a 750 ks Chandra observation the remnant Kepler's supernova AD 1604. The strength and prominence iron emission, together with absence O-rich ejecta, demonstrate that Kepler resulted from thermonuclear supernova, even though evidence for circumstellar interaction is also strong. have analyzed spectra over 100 small regions, find they fall into three classes. (1) vast majority show Fe L emission between 0.7 1 keV Si S Kα emission; we associate these shocked...
We revisit in more detail a model for element abundance fractionation the solar chromosphere, that gives rise to "FIP Effect" corona and wind. Elements with first ionization potential below about 10 eV, i.e. those are predominantly ionized enriched by factor 3-4. propagation of Alfven waves through chromosphere using non-WKB treatment, evaluate ponderomotive force associated these waves. Under conditions, this is generally pointed upwards enhances chromospheric ions corona. Our new approach...
Tungsten was injected by means of laser ablation in both ohmic and additionally heated plasmas the ASDEX Upgrade tokamak experiment. Spectroscopic investigations were performed extreme ultraviolet (EUV) wavelength region, 4 to 140 nm. Besides quasi-continuum structure at ≈ 5 nm emitted tungsten ions around W27+, isolated lines observed same spectral region also range from 12 14 By comparison with calculations HULLAC RELAC codes, these could be identified as transitions bromine nickel-like...
The ultraviolet spectrum of SN 1006 observed by the Hopkins Ultraviolet Telescope (HUT) is modeled to infer degree electron-ion equilibration at nonradiative shocks in remnant. Such an approach possible since has lines (He II λ1640) whose excitation dominated electrons, and others (C IV λ1550, N V λ1240, O VI λ1036) which protons other ions are more important, intensity ratio between these sensitive temperature ratio. We find substantially less than full equilibration, marginally consistent...
We report on the observation of OVII Doppler line broadening in a compact knot at edge SN 1006 detected with Reflective Grating Spectrometer board XMM-Newton. The observed width sigma = 3.4+/-0.5 eV energy 574 indicates an oxygen temperature kT 528+/-150 keV. Combined electron 1.5 keV is direct evidence for non-equilibration high Mach number shocks, and slow subsequent equilibration. emission allows accurate determination ionization state plasma, which characterized by relatively forbidden...
We have measured the absolute polarization of 2${\mathit{p}}^{61}$${\mathit{S}}_{0}$-2${\mathit{p}}^{5}$${(}^{2}$${\mathit{P}}_{3/2}^{\mathit{o}}$)3s[3/2${]}_{2}^{\mathit{o}}$ magnetic quadrupole transition in Ne-like barium, excited an electron-beam ion trap at a variety energies. find strong evidence for existence resonant excitation processes that are not explained by our collisional-radiative calculations even when arising from impact is included. At energies well away where resonances...
view Abstract Citations (113) References (61) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Stellar Coronal Abundances. III. The Solar First Ionization Potential Effect Determined from Full-Disk Observation Laming, J. Martin ; Drake, Widing, Kenneth G. In this paper we reanalyze the full-disk quiet-sun spectrum of Mallinovsky & Heroux (1973) with modern atomic data. purposes are to check our data and methods in other investigations using nearby stars...
A model for element abundance fractionation between the solar chromosphere and corona is further developed. The ponderomotive force due to Alfven waves propagating through, or reflecting from in conditions generally accelerates chromospheric ions, but not neutrals, into corona. This gives rise what has become known as First Ionization Potential (FIP) Effect. We incorporate new physical processes model. ionization balance improved, effect of different approximations discussed. also treat...
It is now well established that Kepler's supernova remnant (SNR) the result of a Type Ia explosion. With an age 407 yr and angular diameter ∼4', Kepler estimated to be between 3.0 7.0 kpc distant. Unlike other Galactic SNRs such as Tycho SN 1006, SNR 0509-67.5 in Large Magellanic Cloud, shows evidence for strong circumstellar interaction. A bowshock structure north thought originate from motion mass-losing system through interstellar medium prior supernova. We present results hydrodynamical...
We analyze the X-ray spectra of 19 main sequence stars observed by Chandra using its LETGS configuration. Emission measure (EM) distributions are computed based on emission line measurements, an analysis that also yields evaluations coronal abundances. The use newer atomic physics data results in significant changes compared to past published analyses. stellar EM correlate with surface flux (F_X) a predictable way, regardless spectral type. Thus, we provide as function F_X, which can be used...
We present initial results from a JWST survey of the youngest Galactic core-collapse supernova remnant Cassiopeia A (Cas A), made up NIRCam and MIRI imaging mosaics that map emission main shell, interior, surrounding circumstellar/interstellar material (CSM/ISM). also four exploratory positions MIRI/MRS IFU spectroscopy sample ejecta, CSM, associated dust representative shocked unshocked regions. Surprising discoveries include: 1) web-like network ejecta filaments resolved to 0.01 pc scales...
Abstract We present JWST observations of the Crab Nebula, iconic remnant historical SN 1054. The include NIRCam and MIRI imaging mosaics plus MIRI/MRS spectra that probe two select locations within ejecta filaments. derive a high-resolution map dust emission show grains are concentrated in innermost, high-density These dense filaments coincide with multiple synchrotron bays around periphery Crab's pulsar wind nebula (PWN). measure spectral index changes small-scale features PWN’s torus...