scholarly journals Calculations of the integral invariant coordinates <I>I</I> and <I>L</I>* in the magnetosphere and mapping of the regions where <I>I</I> is conserved, using a particle tracer (ptr3D v2.0), LANL*, SPENVIS, and IRBEM

2015 ◽  
Vol 8 (9) ◽  
pp. 2967-2975 ◽  
Author(s):  
K. Konstantinidis ◽  
T. Sarris
Keyword(s):  
Magnetic Field ◽  
Particle Motion ◽  
Pitch Angle ◽  
Initial Conditions ◽  
Initial Position ◽  
Space Environment ◽  
Integral Invariant ◽  
Earth’S Magnetosphere ◽  
Earth's Magnetosphere ◽  
Particle Tracer

Abstract. The integral invariant coordinate I and Roederer's L or L* are proxies for the second and third adiabatic invariants, respectively, that characterize charged particle motion in a magnetic field. Their usefulness lies in the fact that they are expressed in more instructive ways than their counterparts: I is equivalent to the path length of the particle motion between two mirror points, whereas L*, although dimensionless, is equivalent to the distance from the center of the Earth to the equatorial point of a given field line, in units of Earth radii, in the simplified case of a dipole magnetic field. However, care should be taken when calculating the above invariants, as the assumption of their conservation is not valid everywhere in the Earth's magnetosphere. This is not clearly stated in state-of-the-art models that are widely used for the calculation of these invariants. The purpose of this work is thus to investigate where in the near-Earth magnetosphere we can safely calculate I and L* with tools with widespread use in the field of space physics, for various magnetospheric conditions and particle initial conditions. More particularly, in this paper we compare the values of I and L* as calculated using LANL*, an artificial neural network developed at the Los Alamos National Laboratory, SPENVIS, a space environment online tool, IRBEM, a software library dedicated to radiation belt modeling, and ptr3D, a 3-D particle tracing code that was developed for this study. We then attempt to quantify the variations between the calculations of I and L* of those models. The deviation between the results given by the models depends on particle initial position, pitch angle and magnetospheric conditions. Using the ptr3D v2.0 particle tracer we map the areas in the Earth's magnetosphere where I and L* can be assumed to be conserved by monitoring the constancy of I for energetic protons propagating forwards and backwards in time. These areas are found to be centered on the noon area, and their size also depends on particle initial position, pitch angle and magnetospheric conditions.

scholarly journals Calculations of the integral invariant coordinates <i>I</i> and <i>L</i><sup>*</sup> in the magnetosphere and mapping of the regions where <i>I</i> is conserved

2014 ◽  
Vol 7 (5) ◽  
pp. 6413-6437
Author(s):  
K. Konstantinidis ◽  
T. Sarris
Keyword(s):  
Magnetic Field ◽  
Particle Motion ◽  
Pitch Angle ◽  
National Laboratory ◽  
Space Environment ◽  
Integral Invariant ◽  
Earth’S Magnetosphere ◽  
Starting Position ◽  
Geocentric Distance ◽  
Earth's Magnetosphere

Abstract. The integral invariant coordinate I and Roederer's L or L* are proxies for the second and third adiabatic invariants respectively, that characterize charged particle motion in a magnetic field. Their usefulness lies in the fact that they are expressed in more instructive ways than their counterparts: I is equivalent to the path length of the particle motion between two mirror points, whereas L*, although dimensionless, is roughly equivalent to the distance from the center of the Earth to the equatorial point of a given field line, in units of Earth radii, in the simplified case of a dipole magnetic field. However, care should be taken when calculating the above invariants, as the assumption of their adiabaticity is not valid everywhere in the Earth's magnetosphere. This is not clearly stated in state-of-the-art models that are widely used for the calculation of these invariants. In this paper, we compare the values of I and L* as calculated using LANLstar, an artificial neural network developed at the Los Alamos National Laboratory, SPENVIS, a space environment related online tool, IRBEM, a source code library dedicated to radiation belt modelling, and a 3-D particle tracing code that was developed for this purpose. We then attempt to quantify the variations between the calculations of I and L* of those models. The deviation between the results given by the models depends on particle starting position geocentric distance, pitch angle and magnetospheric conditions. Using the 3-D tracer we attempt to map the areas in the Earth's magnetosphere where I and L* can be assumed to be conserved by monitoring the constancy of I for energetic proton propagating forwards and backwards in time. These areas are found to be centered on the noon area and their size also depends on particle starting position geocentric distance, pitch angle and magnetospheric conditions.

scholarly journals Solar wind interaction with the Earth's magnetosphere: the role of reconnection in the presence of a large scale sheared flow

2009 ◽  
Vol 16 (1) ◽  
pp. 1-10 ◽  
Author(s):  
F. Califano ◽  
M. Faganello ◽  
F. Pegoraro ◽  
F. Valentini
Keyword(s):  
Magnetic Field ◽  
Solar Wind ◽  
Magnetic Reconnection ◽  
Large Scale ◽  
Initial Conditions ◽  
Magnetic Layer ◽  
Magnetic Islands ◽  
Solar Wind Interaction ◽  
Earth’S Magnetosphere ◽  
Earth's Magnetosphere

Abstract. The Earth's magnetosphere and solar wind environment is a laboratory of excellence for the study of the physics of collisionless magnetic reconnection. At low latitude magnetopause, magnetic reconnection develops as a secondary instability due to the stretching of magnetic field lines advected by large scale Kelvin-Helmholtz vortices. In particular, reconnection takes place in the sheared magnetic layer that forms between adjacent vortices during vortex pairing. The process generates magnetic islands with typical size of the order of the ion inertial length, much smaller than the MHD scale of the vortices and much larger than the electron inertial length. The process of reconnection and island formation sets up spontaneously, without any need for special boundary conditions or initial conditions, and independently of the initial in-plane magnetic field topology, whether homogeneous or sheared.

scholarly journals Simulation of charged particles in Earth's magnetosphere: an approach to the Van Allen belts

2019 ◽  
Vol 65 (1) ◽  
pp. 64
Author(s):  
Jorge Enrique García-Farieta ◽  
A. Hurtado
Keyword(s):  
Magnetic Field ◽  
Initial Conditions ◽  
Charged Particles ◽  
Classical Electrodynamics ◽  
Natural Phenomena ◽  
Earth’S Magnetosphere ◽  
Dipole Magnetic Field ◽  
Van Allen Belts ◽  
Earth's Magnetosphere ◽  
The Magnetic Field

Earth's magnetosphere, beyond protecting the ozone layer, is a natural phenomena which allows to study the interaction between charged particles from solar activity and electromagnetic fields. In this paper we studied trajectories of charged particles interacting with a constant dipole magnetic field as first approach of the Earth's magnetosphere using different initial conditions. As a result of this interaction there is a formation of well defined radiation regions by a confinement of charged particles around the lines of the magnetic field. These regions, called Van Allen radiation belts, are described by classical electrodynamics and appear naturally in the numerical modeling done in this work.

scholarly journals Absence of a long-lived lunar paleomagnetosphere

2021 ◽  
Vol 7 (32) ◽  
pp. eabi7647
Author(s):  
John A. Tarduno ◽  
Rory D. Cottrell ◽  
Kristin Lawrence ◽  
Richard K. Bono ◽  
Wentao Huang ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Lunar Regolith ◽  
The Moon ◽  
Earth’S Magnetosphere ◽  
Solar Winds ◽  
Planetary Bodies ◽  
Earth's Magnetosphere ◽  
Impact Glass ◽  
Magnetic Inclusions

Determining the presence or absence of a past long-lived lunar magnetic field is crucial for understanding how the Moon’s interior and surface evolved. Here, we show that Apollo impact glass associated with a young 2 million–year–old crater records a strong Earth-like magnetization, providing evidence that impacts can impart intense signals to samples recovered from the Moon and other planetary bodies. Moreover, we show that silicate crystals bearing magnetic inclusions from Apollo samples formed at ∼3.9, 3.6, 3.3, and 3.2 billion years ago are capable of recording strong core dynamo–like fields but do not. Together, these data indicate that the Moon did not have a long-lived core dynamo. As a result, the Moon was not sheltered by a sustained paleomagnetosphere, and the lunar regolith should hold buried 3He, water, and other volatile resources acquired from solar winds and Earth’s magnetosphere over some 4 billion years.

At the edge of the Earth’s magnetosphere: a survey by AMPTE-UKS

1989 ◽  
Vol 328 (1598) ◽  
pp. 43-56 ◽  
Keyword(s):  
Boundary Layer ◽  
Dynamic Pressure ◽  
Outer Edge ◽  
Current Layer ◽  
Earth’S Magnetosphere ◽  
Earth's Magnetosphere ◽  
First Results ◽  
New Type ◽  
Particle Tracer ◽  
The Magnetic Field

A survey is made, by using measurements from the Active Magneto spheric Particle Tracer Explorers - United Kingdom Satellite, of the interaction between plasmas of solar and terrestrial origin at the outer edge of the Earth’s magnetosphere. The position of the boundary and its rate of movement are related statistically to solarwind dynamic pressure and its variations. The first results are presented of a new type of analysis which aims to clarify the nature of the boundary layer that develops between the two plasmas by reordering, on the basis of a consistent relation between electron density and temperature, the normally erratic progress made by a spacecraft across the constantly moving region. Distinctive patterns found consistently for the electron and ion transitions suggest that diffusion, viscosity and loss to the atmosphere govern the boundary layer. Various possibilities are discussed for the topology of the region. Electron acceleration within the boundary layer is identified; its cause and relevance to dayside auroral precipitation are discussed. There is an indication that the transition in the magnetic field, across the magnetopause current layer, lies within, rather than immediately outside, the boundary layer.

scholarly journals Interplanetary magnetic field rotations followed from L1 to the ground: the response of the Earth's magnetosphere as seen by multi-spacecraft and ground-based observations

2011 ◽  
Vol 29 (9) ◽  
pp. 1549-1569 ◽  
Author(s):  
M. Volwerk ◽  
J. Berchem ◽  
Y. V. Bogdanova ◽  
O. D. Constantinescu ◽  
M. W. Dunlop ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Solar Wind ◽  
Dynamic Pressure ◽  
Earth’S Magnetosphere ◽  
Solar Wind Magnetic Field ◽  
Earth's Magnetosphere ◽  
High Dynamic ◽  
First Time ◽  
Current Systems ◽  
The Magnetic Field

Abstract. A study of the interaction of solar wind magnetic field rotations with the Earth's magnetosphere is performed. For this event there is, for the first time, a full coverage over the dayside magnetosphere with multiple (multi)spacecraft missions from dawn to dusk, combined with ground magnetometers, radar and an auroral camera, this gives a unique coverage of the response of the Earth's magnetosphere. After a long period of southward IMF Bz and high dynamic pressure of the solar wind, the Earth's magnetosphere is eroded and compressed and reacts quickly to the turning of the magnetic field. We use data from the solar wind monitors ACE and Wind and from magnetospheric missions Cluster, THEMIS, DoubleStar and Geotail to investigate the behaviour of the magnetic rotations as they move through the bow shock and magnetosheath. The response of the magnetosphere is investigated through ground magnetometers and auroral keograms. It is found that the solar wind magnetic field drapes over the magnetopause, while still co-moving with the plasma flow at the flanks. The magnetopause reacts quickly to IMF Bz changes, setting up field aligned currents, poleward moving aurorae and strong ionospheric convection. Timing of the structures between the solar wind, magnetosheath and the ground shows that the advection time of the structures, using the solar wind velocity, correlates well with the timing differences between the spacecraft. The reaction time of the magnetopause and the ionospheric current systems to changes in the magnetosheath Bz seem to be almost immediate, allowing for the advection of the structure measured by the spacecraft closest to the magnetopause.

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