Homayon Aryan

Homayon Aryan
University of California, Los Angeles | UCLA · Department of Atmospheric and Oceanic Sciences (AOS)

PhD

About

28
Publications
3,866
Reads
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202
Citations
Citations since 2016
23 Research Items
194 Citations
201620172018201920202021202201020304050
201620172018201920202021202201020304050
201620172018201920202021202201020304050
201620172018201920202021202201020304050
Additional affiliations
January 2020 - present
University of California, Los Angeles
Position
  • Research Associate
July 2018 - January 2020
The University of Sheffield
Position
  • Research Associate
Description
  • Teachings: Advanced Space Systems and Space Weather (ACS6126) and Space Systems Engineering (ACS327).
May 2015 - June 2018
NASA
Position
  • PostDoc Position
Education
September 2011 - February 2015
The University of Sheffield
Field of study
  • Space Physics: Particle Acceleration in Near Earth Geospace (PhD)
September 2007 - July 2011
The University of Sheffield
Field of study
  • Aerospace Engineering with Private Pilot Licence (MEng: First)

Publications

Publications (28)
Article
Full-text available
Energetic electrons within the Earth's radiation belts represent a serious hazard to geostationary satellites. The interactions of electrons with chorus waves play an important role in both the acceleration and loss of radiation belt electrons. The common approach is to present model wave distributions in the inner magnetosphere under different val...
Article
Full-text available
The interaction of CMEs with the solar wind can lead to the formation of interplanetary shocks. Ions accelerated at these shocks contribute to the solar energetic protons observed in the vicinity of the Earth. Recently a joint analysis of Venus Express (VEX) and STEREO data by Russell et al. (2009) have shown that the formation of strong shocks ass...
Article
Full-text available
A correlation between solar wind velocity (VSW) and energetic electron fluxes (EEF) at the geosynchronous orbit was first identified more than 30 years ago. However, recent studies have shown that the relation between VSW and EEF is considerably more complex than was previously suggested. The application of process identification technique to the e...
Article
Full-text available
Plain Language Summary The relativistic electrons in the Earth's outer radiation belts, also known as “killer electrons,” can pose a huge hazard to the Earth‐orbiting satellites and our unprecedented space‐based connection‐dependent society. Therefore, it is important to investigate the underlying physical mechanism that controls the upper limit fl...
Article
Full-text available
Magnetotail earthward fast flow bursts can transport most magnetic flux and energy into the inner magnetosphere. These fast flow bursts are generally an order of magnitude higher than the typical convection speeds that are azimuthally localised (1–3 RE) and are flanked by plasma vortices, which map to ionospheric plasma vortices of the same sense o...
Article
Full-text available
The dynamics of the radiation belts are largely affected by the resonant interactions of energetic particles with plasma waves, such as whistler mode chorus waves. These waves play a direct and crucial role in the acceleration and loss of radiation belt electrons. The properties of these waves have been investigated thoroughly using various mission...
Preprint
The magnetotail earthward fast flow bursts can transport most of the magnetic flux and energy into the inner magnetosphere. These fast flow bursts are generally an order of magnitude higher than the typical convection speeds, that are azimuthally localized (1–3RE) and are flanked by plasma vortices which map to ionospheric plasma vortices of the sa...
Article
Full-text available
Equatorial magnetosonic waves (EMS), together with chorus and plasmaspheric hiss, play key roles in the dynamics of energetic electron fluxes in the magnetosphere. Numerical models, developed following a first principles approach, that are used to study the evolution of high energy electron fluxes are mainly based on quasilinear diffusion. The appl...
Article
Full-text available
The resonant interaction of energetic particles with plasma waves, such as chorus and plasmaspheric hiss waves, plays a direct and crucial role in the acceleration and loss of radiation belt electrons that ultimately affect the dynamics of the radiation belts. In this study, we use the comprehensive wave data measurements made by the Electric and M...
Article
Full-text available
The electron fluxes at geostationary orbit measured by GOES 13, 14, and 15 spacecraft are modeled using system identification techniques. System identification, similar to machine learning, uses input-output data to train a model, which can then be used to provide forecasts. This study employs the Nonlinear AutoRegressive Moving Average eXogenous (...
Preprint
The Van Allen radiation belts are donut-shaped belts around the Earth that consist of highly energetic particle populations. These trapped energetic particles represent a serious hazard to the electronic components of satellite. The impact can be severe and could lead to permanent failure of individual electronic subsystems and in some cases even l...
Article
Full-text available
The flux of energetic electrons in the outer radiation belt shows a high variability. The interactions of electrons with very low frequency (VLF) chorus waves play a significant role in controlling the flux variation of these particles. Quantifying the effects of these interactions is crucially important for accurately modelling the global dynamics...
Article
Full-text available
Plain Language Summary In space plasmas, oscillations in the background electric and magnetic fields grow from energy sources associated with populations of plasma particles that are not in equilibrium. Once generated, these plasma waves may interact with the background plasma passing their energy back to the particles. In addition, waves at differ...
Presentation
Magnetosonic waves play an important role on the overall dynamics of relativistic radiation belt electrons. Numerical codes modelling the evolution of the radiation belts often account for wave-particle interaction with magnetosonic waves. The diffusion coefficients incorporated in these codes are generally estimated based on the results of statist...
Article
Full-text available
Magnetosonic waves play an important role on the overall dynamics of relativistic radiation belt electrons. Numerical codes modelling the evolution of the radiation belts often account for wave-particle interaction with magnetosonic waves. The diffusion coefficients incorporated in these codes are generally estimated based on the results of statist...
Article
Full-text available
Collisionless shocks are ubiquitous throughout the universe: around stars, supernova remnants, active galactic nuclei, binary systems, comets, and planets. Key information is carried by electromagnetic emissions from particles accelerated by high Mach number collisionless shocks. These shocks are intrinsically nonstationary, and the characteristic...
Article
Full-text available
Statistical wave models, describing the distribution of wave amplitudes as a function of location, geomagnetic activity and other parameters, are needed as the basis to describe the wave particle interactions within numerical models of the radiation belts. In this study, we widen the scope of the statistical wave models by investigating which of th...
Article
Full-text available
Both heliophysics and planetary physics seek to understand the complex nature of the solar wind’s interaction with solar system obstacles like Earth’s magnetosphere, the ionospheres of Venus and Mars, and comets. Studies with this objective are frequently conducted with the help of single or multipoint in situ electromagnetic field and particle obs...
Poster
Numerical simulation studies of the Earth's radiation belts are important to understand the acceleration and loss of energetic electrons. The Comprehensive Inner Magnetosphere-Ionosphere (CIMI) model, along with most other models, require accurate estimates of pitch angle, energy, and cross diffusion of electrons, due to chorus and plasmaspheric hi...
Article
Full-text available
Numerical simulation studies of the Earth's radiation belts are important to understand the acceleration and loss of energetic electrons. The Comprehensive Inner Magnetosphere-Ionosphere (CIMI) model considers the effects of the ring current and plasmasphere on the radiation belts to obtain plausible results. The CIMI model incorporates pitch angle...
Article
Full-text available
Highly energetic electrons in the Earth's Van Allen radiation belts can cause serious damage to spacecraft electronic systems, and affect the atmospheric composition if they precipitate into the upper atmosphere. Whistler mode chorus waves have attracted significant attention in recent decades for their crucial role in the acceleration and loss of...
Article
Full-text available
Reliable forecasts of relativistic electrons at geostationary orbit (GEO) are important for the mitigation of their hazardous effects on spacecraft at GEO. For a number of years the Space Weather Prediction Center at NOAA has provided advanced online forecasts of the fluence of electrons with energy >2 MeV at GEO using the Relativistic Electron For...
Thesis
The radiation belts occupy a vast region of near Earth geospace where many important communication, navigation, Earth observation, and defence satellites operate. In recent decades, demand for space technology has grown dramatically and this is set to grow further as humans become more and more dependent on space technology. Without the operation o...
Article
Full-text available
[1] A correlation between solar wind velocity (VSW) and energetic electron fluxes (EEF) at geosynchronous orbit was first identified more than thirty years ago. However, recent studies have shown that the relation between VSW and EEF is considerably more complex than was previously suggested. Application of process identification technique to the e...

Network

Cited By

Projects

Projects (5)
Project
To study collisionless shocks in space plasma
Project
Plasmaspheric hiss waves are largely responsible for the continuous scattering of radiation belt electrons into the atmospheric loss cone, the decay of energetic electrons in the outer radiation belt during relatively quiet geomagnetic conditions.
Project
To study equatorial magnetosonic waves observed by the Cluster satellites.