R. M. Dewey
A5082122790- Astro and Planetary Science
- Planetary Science and Exploration
- Ionosphere and magnetosphere dynamics
- Solar and Space Plasma Dynamics
- Geomagnetism and Paleomagnetism Studies
- Stellar, planetary, and galactic studies
- Earthquake Detection and Analysis
- Geophysics and Gravity Measurements
- Space Science and Extraterrestrial Life
- Isotope Analysis in Ecology
- Solar Radiation and Photovoltaics
- Ion-surface interactions and analysis
- Space Satellite Systems and Control
- Spacecraft Design and Technology
- Laser-induced spectroscopy and plasma
- SAS software applications and methods
- Space exploration and regulation
- Nuclear Physics and Applications
- Scientific Computing and Data Management
- GNSS positioning and interference
- Magnetic confinement fusion research
- Architecture and Computational Design
- Astronomy and Astrophysical Research
- Precipitation Measurement and Analysis
- 3D Surveying and Cultural Heritage
University of Michigan–Ann Arbor
2016-2025
Laboratory for Atmospheric and Space Physics
2014-2018
University of Colorado Boulder
2015-2016
Coupling between the lower and upper atmosphere, combined with loss of gas from atmosphere to space, likely contributed thin, cold, dry modern Mars. To help understand ongoing ion Mars Atmosphere Volatile Evolution (MAVEN) spacecraft made comprehensive measurements ionosphere, interactions Sun solar wind during an interplanetary coronal mass ejection impact in March 2015. Responses include changes bow shock magnetosheath, formation widespread diffuse aurora, enhancement pick-up ions....
The Mars Atmosphere and Volatile Evolution (MAVEN) mission, during the second of its Deep Dip campaigns, made comprehensive measurements martian thermosphere ionosphere composition, structure, variability at altitudes down to ~130 kilometers in subsolar region. This altitude range contains diffusively separated upper atmosphere just above well-mixed atmosphere, layer peak extreme ultraviolet heating primary reservoir for atmospheric escape. In situ reveal previously unmeasured populations...
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...
Abstract MErcury Surface, Space ENvironment, GEochemistry, and Ranging (MESSENGER) measurements taken during passes over Mercury's dayside hemisphere indicate that on four occasions the spacecraft remained in magnetosheath even though it reached altitudes below 300 km. During these disappearing magnetosphere (DDM) events, did not encounter magnetopause until was at very high magnetic latitudes, ~66 to 80°. These DDM events stand out with respect their extremely solar wind dynamic pressures,...
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....
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...
The ambient solar wind that fills the heliosphere originates from multiple sources in corona and is highly structured. It often described as high-speed, relatively homogeneous, plasma streams coronal holes slow-speed, variable, whose source regions are under debate. A key goal of ESA/NASA's Solar Orbiter mission to identify understand what drives complexity seen heliosphere. By combining magnetic field modelling spectroscopic techniques with high-resolution observations measurements, we show...
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,...
Abstract Mercury's flux transfer event (FTE) showers are dayside magnetopause crossings accompanied by large numbers (≥10) of magnetic ropes (FRs). These shower events common, occurring during 52% (1,953/3,748) the analyzed crossings. Shower observed with shear angles (θ) from 0° to 180° across and magnetosheath plasma β 0.1 10 but most prevalent for high θ low . Individual FR duration correlates positively, while spacing negatively, content core field intensity correlate negatively , they...
Abstract This review paper summarizes the research of Mercury’s magnetosphere in Post-MESSENGER era and compares its dynamics to those other planetary magnetospheres, especially Earth’s magnetosphere. starts by introducing planet Mercury, including interplanetary environment, magnetosphere, exosphere, conducting core. The frequent intense magnetic reconnection on dayside magnetopause, which is represented flux transfer event “shower”, reviewed how they depend magnetosheath plasma β shear...
Proper characterization of particle energization in the solar wind requires observations from thermal through energetic particles multiple elements. Observations situ different energy ranges require instruments that must be properly intercalibrated. Solar Orbiter’s Heavy Ion Sensor (HIS) is a time-of-flight ion mass spectrometer observes heavy composition wind. Suprathermal Spectrograph (SIS) an detector suprathermal energies to lower range particles. We report on intercalibration...
Abstract We investigate Mercury's response to rare, low Alfvénic Mach number solar wind conditions using observations from the Mercury Surface, Space Environment, Geochemistry, and Ranging (MESSENGER) mission. This study provides compelling evidence of altered magnetospheric state under these extreme conditions, including first observational confirmation Alfvén wing formation at planet. Our analysis estimates that upstream during interplanetary coronal mass ejection (ICME) were sub‐to...
Abstract Ion precipitation onto Mercury's surface through its magnetospheric cusps acts as a source of planetary atoms to both exosphere and magnetosphere. Through the process ion sputtering, solar wind ions (∼95% protons) impact regolith liberate material, mostly neutral atoms. We have identified 2760 northern cusp crossings throughout MErcury Surface, Space ENvironment, GEochemistry Ranging (MESSENGER) mission, based on enhancements in proton flux observed by Fast Imaging Plasma...
Abstract Energetic particle bursts associated with dipolarization events within Mercury's magnetosphere were first observed by Mariner 10. The appear analogous to injections accompanying at Earth. Particle Spectrometer (3 s resolution) aboard MESSENGER determined the are composed entirely of electrons energies ≳ 300 keV. Here we use Gamma‐Ray high‐time‐resolution (10 ms) energetic electron measurements examine relationship between and magnetic field in magnetotail. Between March 2013 April...
Machine learning (ML) methods can expand our ability to construct, and draw insight from large datasets. Despite the increasing volume of planetary observations, field has seen few applications ML in comparison other sciences. To support these methods, we propose ten recommendations for bolstering a data-rich future science.
Abstract During Parker Solar Probe (Parker) Encounter 15 (E15), we observe an 18 hr period of near-subsonic ( M S ∼ 1) and sub-Alfvénic (SA), A ⋘ 1, slow-speed solar wind from 22 to 15.6 R ⊙ . As the most extreme SA interval measured date skirting sonic point, it is deepest has probed into formation acceleration region in corona. The stream also by Wind Magnetosonic Multiscale mission near 1 au at times consistent with ballistic propagation this slow stream. We investigate source,...
Abstract Since Parker Solar Probe’s (Parker’s) first perihelion pass at the Sun, large-amplitude Alfvén waves grouped in patches have been observed near Sun throughout mission. Several formation processes for these magnetic switchback suggested with no definitive consensus. To provide insight into their formation, we examine heavy ion properties of several adjacent around Parker’s 11th pass, capitalizing on a spacecraft lineup Orbiter where each samples same solar wind streams over large...
Abstract The MErcury Surface, Space ENvironment, GEochemistry, and Ranging (MESSENGER) mission to Mercury has provided a wealth of new data about energetic particle phenomena. With observations from MESSENGER's Energetic Particle Spectrometer, as well arising electrons recorded by the X‐Ray Spectrometer Gamma‐Ray Neutron (GRNS) instruments, recent work greatly extends our record acceleration, transport, loss at Mercury. combined sets include measurements few keV up several hundred in...
Abstract We present the first observation of fast plasma flows in Mercury's magnetotail. Mercury experiences substorm activity phenomenologically similar to Earth's; however, field‐of‐view limitations Fast Imaging Plasma Spectrometer (FIPS) prevent instrument from detecting sheet. Although FIPS measures incomplete distributions, subsonic impart an asymmetry on partial distribution, even if flow directions are outside field view. combine observations 387 intervals containing magnetic...
Abstract Mercury's nightside magnetosphere is investigated under the impact of a coronal mass ejection (CME) and high‐speed stream (HSS) with MErcury Surface, Space ENviroment, GEochemistry, Ranging (MESSENGER) observations. The CME was shown to produce low plasma (ratio thermal pressure magnetic pressure) magnetosheath, while HSS creates higher magnetosheath. Reconnection at dayside magnetopause found be stronger during than HSS, but both were average condition (Slavin et al., 2014,...
Context. On December 27, 2020, Solar Orbiter completed its first gravity assist manoeuvre of Venus (VGAM1). While this flyby was performed to provide the spacecraft with sufficient velocity get closer Sun and observe poles from progressively higher inclinations, Radio Plasma Wave (RPW) consortium, along other operational in situ instruments, had opportunity perform high cadence measurements study plasma properties induced magnetosphere Venus. Aims. In paper, we review main observations RPW...
At Mercury, several processes can release ions and neutrals out of the planet's surface. Here we present enhancements planetary (Na
Abstract This study investigates the escape of Mercury's sodium‐group ions (Na + ‐group, including with m/q from 21 to 30 amu/e) and their dependence on true anomaly angle (TAA), that is, orbital phase around Sun, using measurements MESSENGER. The are categorized into solar wind, magnetosheath, magnetosphere, further divided four TAA intervals. Na ‐group form plumes in wind higher fluxes along wind's motional electric field. total rates vary 0.2 1 × 10 25 atoms/s magnetosheath being main...