A5077658790- Solar and Space Plasma Dynamics
- Astro and Planetary Science
- Ionosphere and magnetosphere dynamics
- Stellar, planetary, and galactic studies
- Geomagnetism and Paleomagnetism Studies
- Solar Radiation and Photovoltaics
- Gamma-ray bursts and supernovae
- Geophysics and Gravity Measurements
- Planetary Science and Exploration
- Atmospheric Ozone and Climate
- Nuclear Physics and Applications
- Ion-surface interactions and analysis
- Earthquake Detection and Analysis
- Global Energy and Sustainability Research
- Astrophysical Phenomena and Observations
- Magnetic confinement fusion research
- Plasma Diagnostics and Applications
- Laser-induced spectroscopy and plasma
- Market Dynamics and Volatility
- Mass Spectrometry Techniques and Applications
- Astrophysics and Star Formation Studies
- Isotope Analysis in Ecology
- Aeolian processes and effects
- Calibration and Measurement Techniques
- History and Developments in Astronomy
University of Michigan
2016-2025
NOAA Oceanic and Atmospheric Research
2013-2014
Centre de Recherche en Astronomie Astrophysique et Géophysique
2013
University of Liège
2013
Michigan United
2013
The Solar Orbiter mission seeks to make connections between the physical processes occurring at Sun or in solar corona and nature of wind created by those which is subsequently observed spacecraft. also targets itself during its journey from source To meet specific science goals, will be equipped with both remote-sensing in-situ instruments unprecedented measurements atmosphere inner heliosphere. A crucial set provided Wind Analyser (SWA) suite instruments. This consists an Electron System...
After leaving the Sun's corona, solar wind continues to accelerate and cools, but more slowly than expected for a freely expanding adiabatic gas. We use in situ measurements from Parker Solar Probe Orbiter spacecrafts investigate stream of as it traverses inner heliosphere. The observations show heating acceleration plasma between outer edge corona near orbit Venus, connection presence large amplitude Alfv\'en waves. waves are perturbations interplanetary magnetic field that transport...
The heating of ions downstream the x‐line during magnetic reconnection is explored using full‐particle simulations, test particle and analytic analysis. Large‐scale simulations reveal that ion temperature increases sharply across boundary layer separates upstream plasma from Alfvénic outflow. This layer, however, does not take form a classical switch‐off shock as discussed in Petschek model, so cannot be calculated magnetohydrodynamic, slow‐shock prediction. Test trajectories fields crossing...
The changing relationships between solar wind speed, helium abundance, and minor ion charge state are examined over cycle 23. Observations of the abundance relative to hydrogen (AHe ≡ 100 × nHe/nH) by Wind spacecraft used examine dependence AHe on speed activity 1994 2010. This work updates an earlier study from 2004 include recent extreme minimum broadly confirms our previous result that in slow is strongly correlated with sunspot number, reaching its lowest values each minima. During last...
Abstract We seek to understand the composition and variability of fast solar wind (FSW) slow Alfvénic emerging from coronal holes (CHs). leverage an opportune conjunction between Solar Orbiter Parker Probe (PSP) during PSP Encounter 11 include compositional diagnostics Heavy Ion Sensor as these variations provide crucial insights into origin nature wind. use potential field source surface magnetohydrodynamic models connect observed plasma at its footpoint in photosphere compare results with...
We present solar wind Fe charge state data measured on the Advanced Composition Explorer (ACE) from early 1998 to middle of 2000. Average states in are typically around 9+ 11+. However, deviations these average occur, including intervals with a large fraction ≥16+ which consistently associated interplanetary coronal mass ejections (ICMEs). By studying distribution we able extract electron temperatures often exceeding 2 × 10 6 kelvins. also discuss temporal trends events, indicating more...
Solar wind plasma and compositional properties reflect the physical of corona its evolution over time. Studies comparing previous solar minimum with most recent, unusual indicate that significant environmental changes are occurring globally on Sun. For example, magnetic field decreased 30% between last two minima, ionic charge states O have been reported to change toward lower values in fast wind. In this work, we systematically comprehensively analyze during cycle 23 from 2000 2010 while...
Coronal mass ejections (CMEs) are explosive events that escape the Sun's corona carrying solar material and energy into heliosphere. The classic picture of a CME observed in presents "three-part structure," including bright front at leading edge indicating dense plasma, low-density cavity, possible signature an embedded magnetic flux rope, so-called core, high-density region to be associated with erupting filament. Although there experimental analogs first two parts when situ, only handful...
Abstract While the source of fast solar wind is known to be coronal holes, slow has remained a mystery. Long time scale trends in composition and charge states show strong correlations between velocity plasma parameters, yet these have proved ineffective determining source. We take advantage new high resolution (12 min) measurements state abundances at L1 previously identified 90 min quasiperiodic structures probe fundamental timescales variability. The combination temporal clearly...
Aims. Solar Orbiter launched in February 2020 with the goal of revealing connections between Sun’s interior, atmosphere, and heliosphere. The Heavy Ion Sensor (HIS) is a time-of-flight ion mass spectrometer dedicated to measuring heavy ions solar wind. Methods. We present an overview first measurements composition from HIS, reviewing methods used transform spectra obtained on board into scientific data products examining two wind case studies as well statistical properties observed by HIS....
It has been shown that Fe charge states greater than and equal to 16 are often observed in the presence of interplanetary coronal mass ejections (ICMEs) at 1 AU. These elevated states, representative hot source regions on Sun, provide an identifier ICMEs independent expansion processes heliocentric distance. Using this new identifier, we present a comparative study state distributions as function latitude time. We compare data from ACE spacecraft ecliptic plane with Ulysses along its orbit...
Oxygen charge states measured by in situ instrumentation have long been used as a powerful diagnostic of the solar corona and to discriminate between different wind regimes, both because they freeze very close Sun, oxygen element abundance is comparatively high, allowing for statistically relevant measures. Like oxygen, carbon also rather abundant freezes Sun. Here, we show an analysis ionic states. First, through auditory Fourier measurements ion composition ACE/SWICS that some ratios are...
We present a novel procedure for deriving the physical properties of coronal mass ejections (CMEs) in corona. Our methodology uses situ measurements ionic charge states C, O, Si, and Fe heliosphere interprets them context model early evolution interplanetary CME (ICME) plasma, between 2 5 R☉. find that data are best fit by an consists initial heating followed expansion ultimately results cooling. The profile is consistent with compression plasma due to flare reconnection jets cooling...
The bimodal paradigm of solar wind describes a slow situated near the heliospheric current sheet while fast overexpands from poles to fill in remainder heliosphere. In this paper, we challenge and focus here on mid-latitude using three fast-latitude passes completed by Ulysses spacecraft. Based its composition dynamic properties, discuss how differs both fast, polar coronal hole low latitude, streamer-associated wind. Using detailed analysis ionic elemental abundances, as well conclude that...
ABSTRACT We analyze the physical origin of plasmas that are ejected from solar corona. To address this issue, we perform a comprehensive analysis elemental composition interplanetary coronal mass ejections (ICMEs) using recently released data for Fe, Mg, Si, S, C, N, Ne, and He as compared to O H. find ICMEs exhibit systematic abundance increase elements with first ionization potential (FIP) < 10 eV, well significant Ne quasi-stationary wind. ICME have stronger FIP effect than slow wind,...
Abstract We categorize the types of solar wind using a new classification scheme based on location wind’s coronal source regions in atmosphere and near-solar heliosphere. first trace measured by ACE /SWEPAM SWICS from 1998 to 2011 at 1 au back <?CDATA $2.5{R}_{{\rm{s}}}$?> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mn>2.5</mml:mn> <mml:msub> <mml:mrow> <mml:mi>R</mml:mi> </mml:mrow> <mml:mi mathvariant="normal">s</mml:mi> </mml:msub> </mml:math> surface...
Coronal mass ejections (CMEs) are major solar events that known to cause large geomagnetic storms ( Dst < −100 nT). Isolated typically have a main phase of 3–12 hours and recovery around 1 day. However, there some with phases exceeding ∼3 days. We trace the origin these long‐lived (LLGMS) frontside halo CMEs. studied 37 LLGMS nT associated CMEs which occurred during 1998–2002. It is found caused by (1) successive CMEs, accounting for ∼64.9% (24 37); (2) single ∼21.6% (8 (3) high‐speed...
Abstract We examine a three‐dimensional (3‐D) numerical magnetohydrodynamic (MHD) simulation describing very fast interplanetary coronal mass ejection (ICME) propagating from the solar corona to 1 AU. In conjunction with its high speed, ICME evolves in ways that give it unique appearance at AU does not resemble typical ICME. First, as decelerates far Sun wind, filament material back of flux rope pushes way forward through rope. Second, diverging nonradial flows front transport poloidal sides...
Using in situ ion spectrometry data from ACE/SWICS, we determine the solar wind Ne/O elemental abundance ratio and examine its dependence on speed evolution with cycle. We find that is inversely correlated speed, nearly constant fast wind, correlates strongly activity slow wind. In streams speeds above 600 km s−1, = 0.10 ± 0.02, good agreement extensive polar observations by Ulysses/SWICS. below 400 ranges a low of 0.12 0.02 at maximum to high 0.17 0.03 minimum. These measurements place new...
The higher charge states found in slow ($<$400km s$^{-1}$) solar wind streams compared to fast have supported the hypothesis that originates closed coronal loops, and released intermittently through reconnection. Here we examine whether a highly ionized can also form along steady open magnetic field lines. We model steady-state atmosphere using AWSoM, global magnetohydrodynamic driven by Alfv{\'e}n waves, apply an ionization code calculate state evolution modeled This constitutes first...
ABSTRACT Diffuse X-rays from the Local Galaxy ( DXL ) is a sounding rocket mission designed to quantify and characterize contribution of Solar Wind Charge eXchange (SWCX) X-ray Background study properties Hot Bubble (LHB). Based on results mission, we quantified removed SWCX diffuse background measured by ROSAT All Sky Survey. The “cleaned” maps were used investigate physical LHB. Assuming thermal ionization equilibrium, highly uniform temperature distributed around kT = 0.097 keV ± 0.013...
In the corona, plasma is accelerated to hundreds of kilometers per second, and heated temperatures times hotter than Sun's surface, before it escapes form solar wind. Decades space-based experiments have shown that energization process does not stop after escapes. Instead, wind continues accelerate cools far more slowly a freely-expanding adiabatic gas. Recent work suggests fast requires additional momentum beyond what can be provided by observed thermal pressure gradients alone whereas...
Abstract In the corona, plasma is accelerated to hundreds of kilometers per second and heated temperatures times hotter than Sun's surface before it escapes form solar wind. Decades space-based experiments have shown that energization process does not stop after escapes. Instead, wind continues accelerate, cools far more slowly a freely expanding adiabatic gas. Recent work suggests fast requires additional momentum beyond what can be provided by observed thermal pressure gradients alone,...