A5066869132- Astro and Planetary Science
- Geomagnetism and Paleomagnetism Studies
- Planetary Science and Exploration
- Ionosphere and magnetosphere dynamics
- Space Exploration and Technology
- Solar and Space Plasma Dynamics
- Geology and Paleoclimatology Research
- Spacecraft and Cryogenic Technologies
- Stellar, planetary, and galactic studies
- Particle Detector Development and Performance
- Nuclear Physics and Applications
- Space Science and Extraterrestrial Life
- Atmospheric Ozone and Climate
- Earthquake Detection and Analysis
- Astronomical Observations and Instrumentation
- Space Satellite Systems and Control
- History and Developments in Astronomy
- Astrophysics and Cosmic Phenomena
- Inertial Sensor and Navigation
- Geophysics and Gravity Measurements
- X-ray Spectroscopy and Fluorescence Analysis
- Isotope Analysis in Ecology
- Astronomy and Astrophysical Research
- Atmospheric and Environmental Gas Dynamics
- SAS software applications and methods
University of Leicester
2016-2025
Royal Astronomical Society
2022
Johns Hopkins University Applied Physics Laboratory
2020
Wolfson Foundation
2020
Royal Society
2020
Charles River Laboratories (Netherlands)
2016-2018
Abstract BepiColombo is a joint mission between the European Space Agency, ESA, and Japanese Aerospace Exploration JAXA, to perform comprehensive exploration of Mercury. Launched on $20^{\mathrm{th}}$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msup> <mml:mn>20</mml:mn> <mml:mi>th</mml:mi> </mml:msup> </mml:math> October 2018 from spaceport in Kourou, French Guiana, spacecraft now en route Two orbiters have been sent Mercury will be put into dedicated, polar orbits around...
While the terrestrial aurorae are known to be driven primarily by interaction of Earth's magnetosphere with solar wind, there is considerable evidence that auroral emissions on Jupiter and Saturn internal processes, main energy source being planets' rapid rotation. Prior observations have suggested might some influence wind Jupiter's indicated storms can occur at times pressure increases. To investigate in detail dependence processes conditions, a large campaign these planets has been...
The first extended series of observations Saturn's auroral emissions, undertaken by the Hubble Space Telescope in January 2004 conjunction with measurements upstream solar wind and interplanetary magnetic field (IMF) Cassini spacecraft, have revealed a strong response to medium. Following arrival forward shock corotating interaction region compression, bright auroras were observed expand significantly poleward dawn sector such that area polar cap was much reduced, following which morphology...
During 2017, the Cassini fluxgate magnetometer made in situ measurements of Saturn's magnetic field at distances ~2550 ± 1290 kilometers above 1-bar surface during 22 highly inclined Grand Finale orbits. These observations refine extreme axisymmetry internal and show displacement equator northward from planet's physical equator. Persistent small-scale structures, corresponding to high-degree (>3) axisymmetric moments, were observed. This suggests secondary shallow dynamo action...
The ESA-JAXA BepiColombo mission will provide simultaneous measurements from two spacecraft, offering an unprecedented opportunity to investigate magnetospheric and exospheric dynamics at Mercury as well their interactions with the solar wind, radiation, interplanetary dust. Many scientific instruments onboard spacecraft be completely, or partially devoted study near-space environment of complex processes that govern it. issues remain unsolved even after MESSENGER ended in 2015. specific...
Abstract. We consider the flows and currents in Saturn's polar ionosphere which are implied by a three-component picture of large-scale magnetospheric flow driven both planetary rotation solar wind interaction. With increasing radial distance equatorial plane, these components consist region dominated where plasma sub-corotates on closed field lines, surrounding is lost down dusk tail stretching out lines followed plasmoid formation pinch-off, as first described for Jupiter Vasyliunas, an...
We propose a simple illustrative axisymmetric model of the plasma flows and currents that occur in Saturn's polar ionosphere which are due to both internal magnetospheric processes solar wind interaction. The features based on previous physical discussion, guided quantitatively by Voyager observations closed field lines remote‐sensing IR Doppler open lines. With increasing latitude flow represented include region poleward ∼25° colatitude where angular velocities decrease continuously from...
The Magnetospheric Imaging Instrument (MIMI) Ion and Neutral Camera (INCA) on the Cassini spacecraft has recorded abrupt increases in energetic neutral atom flux coming from general direction of Saturn's magnetotail. These bursts ion activity tail are well correlated with enhancements Saturn kilometric radiation. Given similarities between these events substorm Earth, including their dependence interplanetary conditions, we conclude that Earth‐like substorms occur within magnetosphere.
Prompted by recent observations of ion flows from Doppler measurements infrared auroras, we here discuss the nature plasma flow in Jupiter's high‐latitude ionosphere. The physical picture is based on a combination three elements, namely an inner Hill‐type sub‐corotating region containing outward‐diffusing iogenic plasma, outer where lost down tail, principally dusk and midnight sector via reconnection‐related Vasyliunas‐cycle, finally outermost boundary located dawn‐side magnetosphere which...
Outer planet auroras have been imaged for more than a decade, yet understanding their physical origin requires simultaneous remote and in situ observations. The first such measurements at Saturn were obtained January 2007, when the Hubble Space Telescope ultraviolet aurora, while Cassini spacecraft crossed field lines connected to auroral oval high‐latitude magnetosphere near noon. data indicate that noon aurora lies boundary between open‐ closed‐field lines, where layer of upward‐directed...
We have examined residual magnetic field vectors observed in Saturn's magnetosphere during the first 2 years of Cassini mission and fit them to a simple axisymmetric model ring current middle magnetosphere. then examine variations parameters with size In addition, we obtain secondary parameters, including value axial at center (equivalently Dst ) B z0 , total I T flowing modeled region, ratio moment relative dipole field, k RC . Results show that derived increase significantly system size,...
Ring current modeling in Saturn's magnetosphere using Pioneer‐11, Voyager, and Cassini data has shown that the size strength of system grows with extension magnetosphere, governed by solar wind dynamic pressure. Here we show consequent middle field is quasi‐dipolar form when strongly compressed, but extends into a magnetodisc it expanded. We also region occupied modeled ring corresponds to an essentially fixed shell lines expands contracts system, thus mapping almost co‐latitude range...
Pioneer 11 observations from the dawn flank of Saturn's magnetosphere provided evidence for a thin equatorial current sheet. Magnetometer data Cassini orbiter have also revealed presence this sheet and shown it to be consistent feature flank. Arridge et al. (2007) recently investigated stress balance in showed that centrifugal force dominated mechanical stresses beyond radial distance 20–30 R S Saturn. These led interpret as magnetodisc, similar jovian but strongly asymmetric local time. In...
We examine the planetary‐period oscillations in Saturn's magnetic field observed by Cassini spacecraft on 23 near‐equatorial periapsis passes inner magnetosphere spanning October 2004 to July 2006. Overall, we find that phase of is well organized long‐timescale modulation Saturn kilometric radiation (SKR) determined over same interval Kurth et al. (2007), suggesting slow period variation latter relates processes. The relative phases spherical polar r and ϕ components imply presence a...
Abstract We investigate magnetic data showing the presence of field‐aligned magnetosphere‐ionosphere coupling currents on 31 Cassini passes across Saturn's southern postmidnight auroral region. The are strongly modulated in magnitude, form, and position by phase planetary period oscillations (PPOs). PPO‐independent separated from PPO‐related using antisymmetry latter with respect to PPO phase. downward ~1.1 MA per radian azimuth flow over polar open field region indicative significant plasma...
We present the first comparison of Jupiter's auroral morphology with an extended, continuous, and complete set near‐Jupiter interplanetary data, revealing response auroras to conditions. show that for ∼1–3 days following compression region onset, planet's main emission brightened. A duskside poleward also brightened during compressions, as well shallow rarefaction conditions at start program. The power emitted from noon active did not exhibit dependence on any parameter, though typically...
Abstract We investigate the magnetic perturbations associated with field‐aligned currents observed on 34 Cassini passes over premidnight northern auroral region during 2008. These are found to be significantly modulated not only by planetary‐period oscillation (PPO) system, similar southern PPO system previously, but also as well, thus providing first clear evidence of PPO‐related interhemispheric current flow. The principal two systems co‐located in ionospheric colatitude, together...
Abstract A large set of observations Jupiter's ultraviolet aurora was collected with the Hubble Space Telescope concurrently NASA‐Juno mission, during an eight‐month period, from 30 November 2016 to 18 July 2017. These cover Juno orbits 3 7 which in situ and remote sensing instruments, as well other observatories, obtained a wealth unprecedented information on magnetosphere connection its auroral ionosphere. is known vary rapidly, timescales ranging seconds one Jovian rotation. The main...
Abstract The relationship between electron energy flux and the characteristic of distributions in main auroral loss cone bridges gap predictions made by theory measurements just recently available from Juno. For decades such relationships have been inferred remote sensing observations Jovian aurora, primarily Hubble Space Telescope, also more Hisaki. However, to infer these quantities, techniques had assume properties atmospheric structure—leading uncertainties their profile. Juno's arrival...