Rapid Outer Radiation Belt Flux Dropouts and Fast Acceleration During the March 2015 and 2013 Storms: The Role of Ultra‐Low Frequency Wave Transport From a Dynamic Outer Boundary

2020 ◽  
Vol 125 (2) ◽  
Author(s):  
L. G. Ozeke ◽  
I. R. Mann ◽  
L. Olifer ◽  
K. Y. Dufresne ◽  
S. K. Morley ◽  
...  
Keyword(s):  
Radiation Belt ◽  
Outer Boundary ◽  
Low Frequency ◽  
Outer Radiation Belt ◽  
Frequency Wave ◽  
Wave Transport

scholarly journals Plasma Waves in the Inner Magnetosphere

2021 ◽  
pp. 85-119
Author(s):  
Hannu E. J. Koskinen ◽  
Emilia K. J. Kilpua
Keyword(s):  
Radiation Belt ◽  
Low Frequency ◽  
Plasma Waves ◽  
Mhd Waves ◽  
Particle Interactions ◽  
Inner Magnetosphere ◽  
Very Low Frequency ◽  
Link Type ◽  
Wave Modes

AbstractUnderstanding the role of plasma waves, extending from magnetohydrodynamic (MHD) waves at ultra-low-frequency (ULF) oscillations in the millihertz range to very-low-frequency (VLF) whistler-mode emissions at frequencies of a few kHz, is necessary in studies of sources and losses of radiation belt particles. In order to make this theoretically heavy part of the book accessible to a reader, who is not familiar with wave–particle interactions, we have divided the treatise into three chapters. In the present chapter we introduce the most important wave modes that are critical to the dynamics of radiation belts. The drivers of these waves are discussed in Chap. 10.1007/978-3-030-82167-8_5 and the roles of the wave modes as sources and losses of radiation belt particles are dealt with in Chap. 10.1007/978-3-030-82167-8_6.

scholarly journals Constraining the Location of the Outer Boundary of Earth’s Outer Radiation Belt

2021 ◽  
Author(s):  
T. Bloch ◽  
C. E. J. Watt ◽  
M. J. Owens ◽  
R. L. Thompson ◽  
O. Agiwal
Keyword(s):  
Radiation Belt ◽  
Outer Boundary ◽  
Outer Radiation Belt

How Coherent are Flux Variations in the Outer Van Allen Radiation Belt?

2020 ◽  
Author(s):  
Samuel Walton ◽  
Colin Forsyth ◽  
Iain Jonathan Rae ◽  
Clare Watt ◽  
Richard Horne ◽  
...  
Keyword(s):  
Geomagnetic Activity ◽  
Radiation Belt ◽  
Geomagnetic Storms ◽  
Outer Boundary ◽  
Radial Distance ◽  
Radiation Belts ◽  
Outer Radiation Belt ◽  
Electron Population ◽  
Storms And Substorms ◽  
Using Data

<p>The electron population inside Earth’s outer radiation belt is highly variable and typically linked to geomagnetic activity such as storms and substorms. These variations can differ with radial distance, such that the fluxes at the outer boundary are different from those in the heart of the belt. Using data from the Proton Electron Telescope (PET) on board NASA’s Solar Anomalous Magnetospheric Particle Explorer (SAMPEX), we have examined the correlation between electron fluxes at all L's within the radiation belts for a range of geomagnetic conditions, as well as longer-term averages. Our analysis shows that fluxes at L≈2-4 and L≈4-10 are well correlated within these regions, with coefficients in excess of 80%, however, the correlation between these two regions is low. These correlations vary between storm-times and quiet-times. We examine whether, and to what extent this correlation is related to the level of enhancement of the outer radiation belt during geomagnetic storms, and whether the plasmapause plays any role defining the different regions of correlated flux.</p>

scholarly journals The role of drift orbit bifurcations in energization and loss of electrons in the outer radiation belt

2011 ◽  
Vol 116 (A9) ◽  
pp. n/a-n/a ◽  
Author(s):  
A. Y. Ukhorskiy ◽  
M. I. Sitnov ◽  
R. M. Millan ◽  
B. T. Kress
Keyword(s):  
Radiation Belt ◽  
Outer Radiation Belt

scholarly journals Constraining the Location of the Outer Boundary of Earth's Outer Radiation Belt

2021 ◽  
Author(s):  
Téo Bloch ◽  
Clare E. J. Watt ◽  
Mathew J Owens ◽  
Rhys Leighton Thompson ◽  
Omakshi Agiwal
Keyword(s):  
Radiation Belt ◽  
Outer Boundary ◽  
Outer Radiation Belt

scholarly journals Association of radiation belt electron enhancements with earthward penetration of Pc5 ULF waves: a case study of intense 2001 magnetic storms

2015 ◽  
Vol 33 (11) ◽  
pp. 1431-1442 ◽  
Author(s):  
M. Georgiou ◽  
I. A. Daglis ◽  
E. Zesta ◽  
G. Balasis ◽  
I. R. Mann ◽  
...  
Keyword(s):  
Radiation Belt ◽  
Low Frequency ◽  
Recovery Phase ◽  
Wave Activity ◽  
Magnetic Storms ◽  
Ulf Waves ◽  
Relativistic Electrons ◽  
Outer Radiation Belt ◽  
Magnetometer Arrays ◽  
The One

Abstract. Geospace magnetic storms, driven by the solar wind, are associated with increases or decreases in the fluxes of relativistic electrons in the outer radiation belt. We examine the response of relativistic electrons to four intense magnetic storms, during which the minimum of the Dst index ranged from −105 to −387 nT, and compare these with concurrent observations of ultra-low-frequency (ULF) waves from the trans-Scandinavian IMAGE magnetometer network and stations from multiple magnetometer arrays available through the worldwide SuperMAG collaboration. The latitudinal and global distribution of Pc5 wave power is examined to determine how deep into the magnetosphere these waves penetrate. We then investigate the role of Pc5 wave activity deep in the magnetosphere in enhancements of radiation belt electrons population observed in the recovery phase of the magnetic storms. We show that, during magnetic storms characterized by increased post-storm electron fluxes as compared to their pre-storm values, the earthward shift of peak and inner boundary of the outer electron radiation belt follows the Pc5 wave activity, reaching L shells as low as 3–4. In contrast, the one magnetic storm characterized by irreversible loss of electrons was related to limited Pc5 wave activity that was not intensified at low L shells. These observations demonstrate that enhanced Pc5 ULF wave activity penetrating deep into the magnetosphere during the main and recovery phase of magnetic storms can, for the cases examined, distinguish storms that resulted in increases in relativistic electron fluxes in the outer radiation belts from those that did not.

scholarly journals Polarization properties of standing shear Alfvén waves in non-axisymmetric background magnetic fields

2007 ◽  
Vol 25 (3) ◽  
pp. 815-822 ◽  
Author(s):  
K. Kabin ◽  
R. Rankin ◽  
I. R. Mann ◽  
A. W. Degeling ◽  
R. Marchand
Keyword(s):  
Geomagnetic Field ◽  
Radiation Belt ◽  
Low Frequency ◽  
Alfven Waves ◽  
Alfvén Waves ◽  
Ulf Waves ◽  
Outer Radiation Belt ◽  
Simple Description ◽  
The Waves ◽  
Shear Alfven Waves

Abstract. In this paper we present results concerning periods and polarizations of cold plasma ultra-low frequency (ULF) guided Alfvén waves in a non-axisymmetric geomagnetic field. The background geomagnetic field is approximated by a compressed dipole for which we propose a simple description in terms of Euler potentials. This study is motivated by the problem of outer-radiation belt electron acceleration by ULF waves, for which the polarization of the wave is of paramount importance. We consider an approximation appropriate to decoupled Alfvénic waves and find that the polarization of the waves can change significantly with local time. Therefore, the ULF wave's contribution to the MeV electron energization process can be localized in space.

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