J. P. Eastwood - Blackett Laboratory, Imperial College London, UK

J. P. Eastwood
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Name
J. P. Eastwood
Affiliation
Blackett Laboratory, Imperial College London, UK
City
London
Country
United Kingdom

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Solar and Stellar Astrophysics (7)
 
Physics - Space Physics (6)
 
Physics - Plasma Physics (3)
 
Earth and Planetary Astrophysics (3)
 
Physics - Geophysics (2)
 
Instrumentation and Methods for Astrophysics (1)
 
Nuclear Theory (1)

Publications Authored By J. P. Eastwood

We present a major step forward towards accurately predicting the arrivals of coronal mass ejections (CMEs) on the terrestrial planets, including the Earth. For the first time, we are able to assess a CME prediction model using data over almost a full solar cycle of observations with the Heliophysics System Observatory. We validate modeling results on 1337 CMEs observed with the Solar Terrestrial Relations Observatory (STEREO) heliospheric imagers (HI) with data from 8 years of observations by 5 spacecraft in situ in the solar wind, thereby gathering over 600 independent in situ CME detections. Read More

Prediction of the effects of coronal mass ejections (CMEs) on Earth strongly depends on knowledge of the interplanetary magnetic field southward component, Bz. Predicting the strength and duration of Bz inside a CME with sufficient accuracy is currently impossible, which forms the so-called Bz problem. Here, we provide a proof-of-concept of a new method for predicting the CME arrival time, speed, Bz and the resulting Dst index at Earth based only on magnetic field data, measured in situ in the inner heliosphere (< 1AU). Read More

Coronal mass ejections (CMEs) are large-scale eruptions of magnetized plasma that may cause severe geomagnetic storms if Earth-directed. Here we report a rare instance with comprehensive in situ and remote sensing observa- tions of a CME combining white-light, radio, and plasma measurements from four different vantage points. For the first time, we have successfully applied a radio direction-finding technique to an interplanetary type II burst detected by two identical widely separated radio receivers. Read More

The systematic monitoring of the solar wind in high-cadence and high-resolution heliospheric images taken by the Solar-Terrestrial Relation Observatory (STEREO) spacecraft permits the study of the spatial and temporal evolution of variable solar wind flows from the Sun out to 1~AU, and beyond. As part of the EU Framework 7 (FP7) Heliospheric Cataloguing, Analysis and Techniques Service (HELCATS) project, we have generated a catalogue listing the properties of 190 corotating structures well-observed in images taken by the Heliospheric Imager instruments on-board STEREO-A. We present here one of very few long-term analyses of solar wind structures advected by the background solar wind. Read More

Magnetic reconnection is a fundamental process in solar system and astrophysical plasmas, through which stored magnetic energy associated with current sheets is converted into thermal, kinetic and wave energy. Magnetic reconnection is also thought to be a key process involved in shedding internally produced plasma from the giant magnetospheres at Jupiter and Saturn through topological reconfiguration of the magnetic field. The region where magnetic fields reconnect is known as the diffusion region and in this letter we report on the first encounter of the Cassini spacecraft with a diffusion region in Saturn's magnetotail. Read More

Using multipoint observations we show, for the first time, that Foreshock Bubbles (FBs) have a global impact on Earth's magnetosphere. We show that an FB, a transient kinetic phenomenon due to the interaction of backstreaming suprathermal ions with a discontinuity, modifies the total pressure upstream of the bow shock showing a decrease within the FB's core and sheath regions. Magnetosheath plasma is accelerated towards the the intersection of the FB's current sheet with the bow shock resulting in fast, sunward, flows as well as outward motion of the magnetopause. Read More

While pressure balance can predict how far the magnetopause will move in response to an upstream pressure change, it cannot determine how fast the transient reponse will be. Using Time History of Events and Macroscale Interactions during Substorms (THEMIS), we present multipoint observations revealing, for the first time, strong (thermal + magnetic) pressure gradients in the magnetosheath due to a foreshock transient, most likely a Hot Flow Anomaly (HFA), which decreased the total pressure upstream of the bow shock. By converting the spacecraft time series into a spatial picture, we quantitatively show that these pressure gradients caused the observed acceleration of the plasma, resulting in fast sunward magnetosheath flows ahead of a localised outward distortion of the magnetopause. Read More

EASY-II is designed as a functional replacement for the previous European Activation System, EASY-2010. It has extended nuclear data and new software, FISPACT-II, written in object-style Fortran to provide new capabilities for predictions of activation, transmutation, depletion and burnup. The new FISPACT-II code has allowed us to implement many more features in terms of energy range, up to GeV; incident particles: alpha, gamma, proton, deuteron and neutron; and neutron physics: self-shielding effects, temperature dependence, pathways analysis, sensitivity and error estimation using covariance data. Read More

We present multi-point in situ observations of a complex sequence of coronal mass ejections (CMEs) which may serve as a benchmark event for numerical and empirical space weather prediction models. On 2010 August 1, instruments on various space missions (Solar Dynamics Observatory/ Solar and Heliospheric Observatory/Solar-TErrestrial-RElations-Observatory) monitored several CMEs originating within tens of degrees from solar disk center. We compare their imprints on four widely separated locations, spanning 120 degree in heliospheric longitude, with radial distances from the Sun ranging from MESSENGER (0. Read More

We study the interaction of two successive coronal mass ejections (CMEs) during the 2010 August 1 events using STEREO/SECCHI COR and HI data. We obtain the direction of motion for both CMEs by applying several independent reconstruction methods and find that the CMEs head in similar directions. This provides evidence that a full interaction takes place between the two CMEs that can be observed in the HI1 field-of-view. Read More

2011Jul
Affiliations: 1University College London, Mullard Space Science Laboratory, Holmbury St Mary, Dorking, Surrey, UK, 2Department of Physics and Astronomy, University of Leicester, UK, 3Blackett Laboratory, Imperial College London, UK, 4NASA Goddard Space Flight Center, Greenbelt, MD, 5Department of Physics and Astronomy, University of Leicester, UK, 6Blackett Laboratory, Imperial College London, UK, 7Department of Physics and Astronomy, University of Leicester, UK, 8Blackett Laboratory, Imperial College London, UK, 9University College London, Mullard Space Science Laboratory, Holmbury St Mary, Dorking, Surrey, UK, 10University College London, Mullard Space Science Laboratory, Holmbury St Mary, Dorking, Surrey, UK, 11Astrium Ltd, Stevenage, UK, 12Department of Physics and Astronomy, University of Leicester, UK, 13University College London, Mullard Space Science Laboratory, Holmbury St Mary, Dorking, Surrey, UK, 14Astrium Ltd, Stevenage, UK, 15Department of Physics and Astronomy, University of Leicester, UK, 16University College London, Mullard Space Science Laboratory, Holmbury St Mary, Dorking, Surrey, UK, 17NASA Goddard Space Flight Center, Greenbelt, MD, 18Department of Physics and Astronomy, University of Leicester, UK, 19University College London, Mullard Space Science Laboratory, Holmbury St Mary, Dorking, Surrey, UK, 20Department of Physics and Astronomy, University of Leicester, UK, 21University College London, Mullard Space Science Laboratory, Holmbury St Mary, Dorking, Surrey, UK, 22LATMOS/Institute Pierre Simon Laplace, Paris, France, 23Department of Physics and Astronomy, University of Leicester, UK, 24NASA Goddard Space Flight Center, Greenbelt, MD, 25Department of Physics and Astronomy, University of Leicester, UK

Planetary plasma and magnetic field environments can be studied by in situ measurements or by remote sensing. While the former provide precise information about plasma behaviour, instabilities and dynamics on local scales, the latter offers the global view necessary to understand the overall interaction of the magnetospheric plasma with the solar wind. Here we propose a novel and more elegant approach employing remote X-ray imaging techniques, which are now possible thanks to the relatively recent discovery of solar wind charge exchange X-ray emissions in the vicinity of the Earth's magnetosphere. Read More

The propagation of reconnection signatures and their associated energy are examined using kinetic particle-in-cell simulations and Cluster satellite observations. It is found that the quadrupolar out-of-plane magnetic field near the separatrices is associated with a kinetic Alfv\'en wave. For magnetotail parameters, the parallel propagation of this wave is super-Alfv\'enic (V_parallel ~ 1500 - 5500 km/s) and generates substantial Poynting flux (S ~ 10^-5 - 10^-4 W/m^2) consistent with Cluster observations of magnetic reconnection. Read More

Type III solar radio storms, observed at frequencies below approximately 16 MHz by space borne radio experiments, correspond to the quasi-continuous, bursty emission of electron beams onto open field lines above active regions. The mechanisms by which a storm can persist in some cases for more than a solar rotation whilst exhibiting considerable radio activity are poorly understood. To address this issue, the statistical properties of a type III storm observed by the STEREO/WAVES radio experiment are presented, examining both the brightness distribution and (for the first time) the waiting-time distribution. Read More