Simulation of radiation belt dynamics driven by solar wind variations

1999 ◽  
pp. 171-182 ◽  
Author(s):  
M. K. Hudson ◽  
S. R. Elkington ◽  
J. G. Lyon ◽  
C. C. Goodrich ◽  
T. J. Rosenberg
Keyword(s):  
Solar Wind ◽  
Radiation Belt

scholarly journals Multi-satellite simultaneous observations of magnetopause and atmospheric losses of radiation belt electrons during an intense solar wind dynamic pressure pulse

2016 ◽  
Vol 34 (5) ◽  
pp. 493-509 ◽  
Author(s):  
Zheng Xiang ◽  
Binbin Ni ◽  
Chen Zhou ◽  
Zhengyang Zou ◽  
Xudong Gu ◽  
...  
Keyword(s):  
Solar Wind ◽  
Radiation Belt ◽  
Pressure Pulse ◽  
Electron Flux ◽  
Dynamic Pressure ◽  
Energetic Electron ◽  
Solar Wind Dynamic Pressure ◽  
Angle Scattering ◽  
Radiation Belt Electrons ◽  
Atmospheric Loss

<p><strong>Abstract.</strong> Radiation belt electron flux dropouts are a kind of drastic variation in the Earth's magnetosphere, understanding of which is of both scientific and societal importance. Using electron flux data from a group of 14 satellites, we report multi-satellite simultaneous observations of magnetopause and atmospheric losses of radiation belt electrons during an event of intense solar wind dynamic pressure pulse. When the pulse occurred, magnetopause and atmospheric loss could take effect concurrently contributing to the electron flux dropout. Losses through the magnetopause were observed to be efficient and significant at <i>L</i> ≳ 5, owing to the magnetopause intrusion into <i>L</i> ∼ 6 and outward radial diffusion associated with sharp negative gradient in electron phase space density. Losses to the atmosphere were directly identified from the precipitating electron flux observations, for which pitch angle scattering by plasma waves could be mainly responsible. While the convection and substorm injections strongly enhanced the energetic electron fluxes up to hundreds of keV, they could delay other than avoid the occurrence of electron flux dropout at these energies. It is demonstrated that the pulse-time radiation belt electron flux dropout depends strongly on the specific interplanetary and magnetospheric conditions and that losses through the magnetopause and to the atmosphere and enhancements of substorm injection play an essential role in combination, which should be incorporated as a whole into future simulations for comprehending the nature of radiation belt electron flux dropouts.</p>

scholarly journals Magnetospheric Response to Solar Wind Forcing: ULF Wave – Particle Interaction Perspective

2021 ◽  
Author(s):  
Qiugang Zong
Keyword(s):  
Solar Wind ◽  
Radiation Belt ◽  
Ring Current ◽  
Dynamic Pressure ◽  
Plasma Heating ◽  
Interplanetary Shock ◽  
Wind Forcing ◽  
Ulf Waves ◽  
Radiation Belt Electrons ◽  
The Impact

Abstract. Solar wind forcing, e.g. interplanetary shock and/or solar wind dynamic pressure pulses impact on the Earth’s magnetosphere manifests many fundamental important space physics phenomena including producing electromagnetic waves, plasma heating and energetic particle acceleration. This paper summarizes our present understanding of the magnetospheric response to solar wind forcing in the aspects of radiation belt electrons, ring current ions and plasmaspheric plasma physics based on in situ spacecraft measurements, ground-based magnetometer data, MHD and kinetic simulations. Magnetosphere response to solar wind forcing, is not just a “one-kick” scenario. It is found that after the impact of solar wind forcing on the Earth’s magnetosphere, plasma heating and energetic particle acceleration started nearly immediately and could last for a few hours. Even a small dynamic pressure change of interplanetary shock or solar wind pressure pulse can play a non-negligible role in magnetospheric physics. The impact leads to generate series kind of waves including poloidal mode ultra-low frequency (ULF) waves. The fast acceleration of energetic electrons in the radiation belt and energetic ions in the ring current region response to the impact usually contains two contributing steps: (1) the initial adiabatic acceleration due to the magnetospheric compression; (2) followed by the wave-particle resonant acceleration dominated by global or localized poloidal ULF waves excited at various L-shells. Generalized theory of drift and drift-bounce resonance with growth or decay localized ULF waves has been developed to explain in situ spacecraft observations. The wave related observational features like distorted energy spectrum, boomerang and fishbone pitch angle distributions of radiation belt electrons, ring current ions and plasmaspheric plasma can be explained in the frame work of this generalized theory. It is worthy to point out here that poloidal ULF waves are much more efficient to accelerate and modulate electrons (fundamental mode) in the radiation belt and charged ions (second harmonic) in the ring current region. The results presented in this paper can be widely used in solar wind interacting with other planets such as Mercury, Jupiter, Saturn, Uranus and Neptune, and other astrophysical objects with magnetic fields.

scholarly journals The cusp: a window for particle exchange between the radiation belt and the solar wind

2006 ◽  
Vol 24 (11) ◽  
pp. 3131-3137 ◽  
Author(s):  
X.-Z. Zhou ◽  
T. A. Fritz ◽  
Q.-G. Zong ◽  
Z. Y. Pu ◽  
Y.-Q. Hao ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Solar Wind ◽  
Open Field ◽  
Test Particle ◽  
Radiation Belt ◽  
Magnetospheric Convection ◽  
Cusp Region ◽  
Particle Simulations ◽  
Particle Exchange ◽  
Field Lines

Abstract. The study focuses on a single particle dynamics in the cusp region. The topology of the cusp region in terms of magnetic field iso-B contours has been studied using the Tsyganenko 96 model (T96) as an example, to show the importance of an off-equatorial minimum on particle trapping. We carry out test particle simulations to demonstrate the bounce and drift motion. The "cusp trapping limit" concept is introduced to reflect the particle motion in the high latitude magnetospheric region. The spatial distribution of the "cusp trapping limit" shows that only those particles with near 90° pitch-angles can be trapped and drift around the cusp. Those with smaller pitch angles may be partly trapped in the iso-B contours, however, they will eventually escape along one of the magnetic field lines. There exist both open field lines and closed ones within the same drift orbit, indicating two possible destinations of these particles: those particles being lost along open field lines will be connected to the surface of the magnetopause and the solar wind, while those along closed ones will enter the equatorial radiation belt. Thus, it is believed that the cusp region can provide a window for particle exchange between these two regions. Some of the factors, such as dipole tilt angle, magnetospheric convection, IMF and the Birkeland current system, may influence the cusp's trapping capability and therefore affect the particle exchanging mechanism. Their roles are examined by both the analysis of cusp magnetic topology and test particle simulations.

scholarly journals The relativistic electron response in the outer radiation belt during magnetic storms

2002 ◽  
Vol 20 (7) ◽  
pp. 957-965 ◽  
Author(s):  
R. H. A. Iles ◽  
A. N. Fazakerley ◽  
A. D. Johnstone ◽  
N. P. Meredith ◽  
P. Bühler
Keyword(s):  
Magnetic Field ◽  
Solar Wind ◽  
Wind Speed ◽  
Interplanetary Magnetic Field ◽  
Relativistic Electron ◽  
Radiation Belt ◽  
Solar Wind Speed ◽  
Recovery Phase ◽  
Magnetic Storms ◽  
Outer Radiation Belt

Abstract. The relativistic electron response in the outer radiation belt during magnetic storms has been studied in relation to solar wind and geomagnetic parameters during the first six months of 1995, a period in which there were a number of recurrent fast solar wind streams. The relativistic electron population was measured by instruments on board the two microsatellites, STRV-1a and STRV-1b, which traversed the radiation belt four times per day from L ~ 1 out to L ~ 7 on highly elliptical, near-equatorial orbits. Variations in the E > 750 keV and E > 1 MeV electrons during the main phase and recovery phase of 17 magnetic storms have been compared with the solar wind speed, interplanetary magnetic field z-component, Bz , the solar wind dynamic pressure and Dst *. Three different types of electron responses are identified, with outcomes that strongly depend on the solar wind speed and interplanetary magnetic field orientation during the magnetic storm recovery phase. Observations also confirm that the L-shell, at which the peak enhancement in the electron count rate occurs has a dependence on Dst *.Key words. Magnetospheric physics (energetic particles, trapped; storms and substorms) – Space plasma physics (charged particle motion and accelerations)

Determining latitudinal extent of energetic electron precipitation using MEPED on-board NOAA POES

2020 ◽  
Author(s):  
Eldho Midhun Babu ◽  
Hilde Nesse Tyssøy ◽  
Christine Smith-Johnsen ◽  
Ville Aleksi Maliniemi ◽  
Josephine Alessandra Salice ◽  
...  
Keyword(s):  
Solar Wind ◽  
Radiation Belt ◽  
Climate Models ◽  
Stratospheric Ozone ◽  
Energetic Electron ◽  
Radiation Belts ◽  
Atmospheric Dynamics ◽  
Electron Precipitation ◽  
Atmospheric Effects ◽  
The Earth

&lt;p&gt;Energetic electron precipitation (EEP) from the plasma sheet and the radiation belts, can collide with gases in the atmosphere and deposit their energy. EEP increase the production of NOx and HOx, which will catalytically destroy stratospheric ozone, an important element of atmospheric dynamics. The particle precipitation also causes variation in the radiation belt population. Therefore, measurement of latitudinal extend of the precipitation boundaries is important in quantifying atmospheric effects of Sun-Earth interaction and threats to spacecrafts and astronauts in the Earth&amp;#8217;s radiation belt. &lt;br&gt;This study uses measurements by MEPED detectors of six NOAA/POES and EUMETSAT/METOP satellites during the year 2010 to determine the latitudinal boundaries of EEP and its variability with geomagnetic activity and solar wind drivers. Variation of the boundaries with respect to different particle energies and magnetic local time is studied. The result will be a key element for constructing a model of EEP variability to be applied in atmosphere climate models.&lt;/p&gt;

Radiation belt electrons respond to multiple solar wind inputs

2007 ◽  
Vol 112 (A6) ◽  
pp. n/a-n/a ◽  
Author(s):  
E. J. Rigler ◽  
M. Wiltberger ◽  
D. N. Baker
Keyword(s):  
Solar Wind ◽  
Radiation Belt ◽  
Radiation Belt Electrons

scholarly journals Radial transport of radiation belt electrons due to stormtime Pc5 waves

2009 ◽  
Vol 27 (5) ◽  
pp. 2173-2181 ◽  
Author(s):  
A. Y. Ukhorskiy ◽  
M. I. Sitnov ◽  
K. Takahashi ◽  
B. J. Anderson
Keyword(s):  
Solar Wind ◽  
Radiation Belt ◽  
Electron Interaction ◽  
Ulf Waves ◽  
Electron Drift ◽  
Radial Transport ◽  
Drift Motion ◽  
The Third ◽  
Third Invariant ◽  
Azimuthal Wave

Abstract. During geomagnetic storms relativistic electron fluxes in the outer radiation belt exhibit dynamic variability over multiple orders of magnitude. This requires radial transport of electrons across their drift shells and implies violation of their third adiabatic invariant. Radial transport is induced by the interaction of the electron drift motion with electric and magnetic field fluctuations in the ULF frequency range. It was previously shown that solar-wind driven ULF waves have long azimuthal wave lengths and thus can violate the third invariant of trapped electrons in the process of resonant interaction with their gradient-curvature motion. However, the amplitude of solar-wind driven ULF waves rapidly decreases with decreasing L. It is therefore not clear what mechanisms are responsible for fast transport rates observed inside the geosynchronous orbit. In this paper we investigate wether stormtime Pc5 waves can contribute to this process. Stormtime Pc5s have short azimuthal wave lengths and therefore cannot exhibit resonance with the the electron drift motion. However we show that stormtime Pc5s can cause localized random scattering of electron drift motion that violates the third invariant. According to our results electron interaction with stormtime Pc5s can produce rapid radial transport even as low as L≃4. Numerical simulations show that electron transport can exhibit large deviations from radial diffusion. The diffusion approximation is not valid for individual storms but only applies to the statistically averaged response of the outer belt to stormtime Pc5 waves.

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