Space Plasma Physics

Interplanetary Evolution of fast Coronal Mass Ejections, Shocks and Type II Radio Bursts emission

by Pedro Corona-Romero

Co-authored with J. A. GONZALEZ-ESPARZA, E. AGUILAR-RODRIGUEZ. In revision in Solar Physics

Fast CMEs driving interplanetary shocks are one of the most important space weather phenomena. We present an analytic... more Fast CMEs driving interplanetary shocks are one of the most important space weather phenomena. We present an analytic model to study the evolution of these events in the interplanetary medium. The model shows that the CME/shock evolution is constituted by three phases: 1) driving, 2) decoupling; and 3) decaying. We compare the model's predictions with some study cases using coronograph, type II radio burst emissions and in-situ data. We found a good agreement between the model and the observational data. The model reproduces the shock-ICME evolution and the type II drift spectra.

A stationary bow shock model for plasmas: the spherical blunt obstacle problem

by Pedro Corona-Romero

Co-authored with J.A. Gonzalez-Esparza. In revision in Advances in Space Research.

We present an analytic model of stationary bow shock which describes the interaction between a supermagnetosonic... more We present an analytic model of stationary bow shock which describes the interaction between a supermagnetosonic ambient wind and an obstacle with spherical-like frontal shape. We develop expressions for the bow shocks geometry and the physical properties of the plasma sheath as functions of the upstream conditions. The model allows to use any value of the upstream Mach number and the polytropic index. The solution is limited to axisymmetric magnetic fields. The model points out the influence of the politropic index for the magnetosheath compression and the sbow shock shape. If the Mach number is small the upstream magnetic field orientation can affect the bow shock shape. We compare our results with other models and with in-situ data. By comparing our solution with observational data point we find a reasonable qualitative agreement; however, it seems that our model underestimates the magnetosheath size.

Dynamics of Coronal Mass Ejections in the interplanetary medium: an analytic perspective

by Pedro Corona-Romero

Co-authored with J.A. Gonzalez-Esparza. Draft in preparation for Journal of Geophysical Research.

We present a study about the posible forces, according the magnetohidrodynamics theory, goberning the propagation of... more We present a study about the posible forces, according the magnetohidrodynamics theory, goberning the propagation of coronal mass ejections (CMEs) along their propagation thorugh interplanetary (IP) medium. Such forces arise from the interaction between the CME and the ambient solar wind (SW). We also compare and discuss of some analytic approches to modeling the CME-SW dynamic coupling.

Identification of Kinetic Alfven Wave Turbulence in the Solar Wind

by Christopher Chen

C. S. Salem, G. G. Howes, D. Sundkvist, S. D. Bale, C. C. Chaston, C. H. K. Chen, F. S. Mozer
Astrophys. J. Lett. 745 L9 (2012)

Anisotropy in Space Plasma Turbulence: Solar Wind Observations

by Christopher Chen

T. S. Horbury, R. T. Wicks, C. H. K. Chen
Space Sci. Rev. (online first), (2011)

Analysis and Simulations of Low Power Plasma Blasting for processing Lunar Materials

by Zachary Burell

Trajectories of charged particles trapped in Earth's magnetic field

by Kaan Öztürk

Submitted to American Journal of Physics.
Source code of programs can be downloaded from the ArXiv site, or from https://sites.google.com/site/mkaanozturk/programs

I outline the theory of relativistic charged-particle motion in the magnetosphere in a way suitable for undergraduate... more I outline the theory of relativistic charged-particle motion in the magnetosphere in a way suitable for undergraduate courses. I discuss particle and guiding center motion, derive the three adiabatic invariants associated with them, and present particle trajectories in a dipolar field. I provide twelve computational exercises that can be used as classroom assignments or for self-study. Two of the exercises, drift-shell bifurcation and Speiser orbits, are adapted from active magnetospheric research. The Python code provided in the supplement can be used to replicate the trajectories and can be easily extended for different field geometries.

Detection and Analysis of RF Data from Hypervelocity Impacts

by Theresa Johnson

3rd AIAA Atmospheric Space Environments Conference

Theresa Johnson, Ivan Linscott, Sigrid Close, David Strauss, Nicolas Lee, Richard Adamo, Anna Mocker, Ralf Srama, Sebastian Bugiel

Ground based tests were performed at the Max-Planck-Institute für Kernphysik Van de Graaff accelerator in Heidelberg,... more Ground based tests were performed at the Max-Planck-Institute für Kernphysik Van de Graaff accelerator in Heidelberg, Germany to explore radiofrequency (RF) emission associated with hypervelocity particle impact induced plasma. Meteoroids and dust traveling between 11 and 72.8 km/s are constantly bombarding spacecraft while on orbit. These hypervelocity particles may cause electrical anomalies in satellites through electromagnetic pulse (EMP) or electrostatic discharge (ESD). Ground tests were conducted by firing iron dust particles at speeds in excess of 11 km/s at target materials situated in a 1m diameter vacuum chamber. A set of broadband log-periodic dipole antenna, VLF loops, and a point electric field sensor are used to detect emission. The signal is dissected in order to corroborate the model of RF emission due to coherent plasma oscillation.

Numeric and analytic study of interplanetary coronal mass ejection and shock evolution: Driving, decoupling, and decaying

by Pedro Corona-Romero

Co-authored with J.A. Gonzalez-Esparza. Journal of Geophysical Research, 116, 2011.

We analyze the heliocentric evolution of fast interplanetary counterparts of coronal mass ejections (ICMEs) and their... more We analyze the heliocentric evolution of fast interplanetary counterparts of coronal mass ejections (ICMEs) and their transient shocks to investigate how and where they decelerate in the interplanetary medium. We employ two one-dimensional hydrodynamic models, analytic and numeric, to study three fast CME events. We focus on the transferring of momentum from the ICME to the shock. The two models show that initially the fast ICME propagates at about a constant speed and drives the shock (driving stage) until it reaches a certain distance from which it decelerates and decouples from the shock (decoupling process). Then the ICME and its shock decelerate (decaying stage). This deceleration depends on the speed difference with respect to the ambient wind and tends to a negligible value when the ICME-shock approaches to the ambient wind speed. The location and duration of these propagation stages depend on the initial CME conditions and the ambient wind characteristics. We present a parametric study to compare the results by the analytic and numeric models, showing the variations of their results as a function of the initial conditions. We perform three study cases to compare the model's predictions with a set of speed measurements of ICME-shock events.

Multidimensional simulations of magnetic field amplification and electron acceleration to near-energy equipartition with ions by a mildly relativistic quasi-parallel …

by Gareth Murphy

Anisotropy of Alfvenic Turbulence in the Solar Wind and Numerical Simulations

by Christopher Chen

C. H. K. Chen, A. Mallet, T. A. Yousef, A. A. Schekochihin, T. S. Horbury
Mon. Not. R. Astron. Soc. 415 3219 (2011)

Frame Dependence of the Electric Field Spectrum of Solar Wind Turbulence

by Christopher Chen

C. H. K. Chen, S. D. Bale, C. Salem, F. S. Mozer
Astrophys. J. Lett. 737 L41 (2011)

Quantum theory of frequency shift of an electromagnetic wave interacting with a plasma

by Angelo Tartaglia

Published on Physical Review E, vol. 55, pp. 7457-7461, (1997)

In this paper we calculate the frequency shift induced on a photon by the interaction with a low density electronic... more In this paper we calculate the frequency shift induced on a photon by the interaction with a low density electronic plasma. The technique is the standard perturbation theory of quantum electrodynamics, taking into account the many body character of the plasma. The shift in the nonrelativistic approximation is shown to be blue. Besides the quantum shift, the known classical effects and the correct temperature dependence are also obtained. Finally the limits of the approximations used are discussed.

Interplanetary evolution of fast CMEs-shocks and type II burst emission

by Pedro Corona-Romero

Co-authored with J.A. Gonzalez-Esparza. American Geophysical Union, Fall Meeting 2010.

Fast CMEs driving interplanetary shocks are one of the most important space weather phenomena. We present an analytic... more Fast CMEs driving interplanetary shocks are one of the most important space weather phenomena. We present an analytic model to study the evolution of these events in the interplanetary medium. The model shows that the CME/shock evolution is constituted by three phases: 1) driving, 2) decoupling; and 3) decaying. We compare the model's predictions with some study cases using coronograph, type II radio burst emissions and in-situ data. We found a good agreement between the model and the observational data. The model reproduces the shock-ICME evolution and the type II drift spectra.

Numerical Study of CME-like disturbances. 1-D simulations

by Pedro Corona-Romero

Co-authored with Gonzalez-Esparza, A.; Jeyakumar, S.; Casillas Perez, G. American Geophysical Union, Spring Meeting 2007

We present a parametric study of ICME-like disturbances from close to the Sun (18 solar radii) to 1 AU. This is a 1-D... more We present a parametric study of ICME-like disturbances from close to the Sun (18 solar radii) to 1 AU. This is a 1-D HD model using the ZEUS 3D code (Stone and Norman, 1992). With this study we illuminate some basic aspects of the heliocentric evolution of these disturbances in the inner heliosphere. After their injection, the fast ICME-like disturbances present two deceleration steps: a slow deceleration propagation in the inner trajectory, and, after reaching a critical distance (at about .45 AU), an exponential deceleration propagation where the ICME- like velocity tends to equalize the ambient wind speed. This critical distance depends on the ICME initial parameters and the ambient wind characteristics.

A numerical study of geometry dependent errors in velocity, temperature, and density measurements from single grid planar retarding potential analyzers

by Jeff Klenzing

R. L. Davidson, G. D. Earle, J. H. Klenzing, and R. A. Heelis, published in Phys. Plasmas, 2010.

Planar retarding potential analyzers (RPAs) have been utilized numerous times on high profile missions such as the... more Planar retarding potential analyzers (RPAs) have been utilized numerous times on high profile missions such as the Communications/Navigation Outage Forecast System and the Defense Meteorological Satellite Program to measure plasma composition, temperature, density, and the velocity component perpendicular to the plane of the instrument aperture. These instruments use biased grids to approximate ideal biased planes. These grids introduce perturbations in the electric potential distribution inside the instrument and when unaccounted for cause errors in the measured plasma parameters. Traditionally, the grids utilized in RPAs have been made of fine wires woven into a mesh. Previous studies on the errors caused by grids in RPAs have approximated woven grids with a truly flat grid. Using a commercial ion optics software package, errors in inferred parameters caused by both woven and flat grids are examined. A flat grid geometry shows the smallest temperature and density errors, while the double thick flat grid displays minimal errors for velocities over the temperature and velocity range used. Wire thickness along the dominant flow direction is found to be a critical design parameter in regard to errors in all three inferred plasma parameters. The results shown for each case provide valuable design guidelines for future RPA development.

Observations of DC electric fields in the low-latitude ionosphere and their variations with local time, longitude, and plasma density during extreme solar minimum

by Jeff Klenzing

R. F. Pfaff et al, published in J. Geophys. Res. 2010

DC electric fields and associated E × B plasma drifts detected with the double-probe experiment on the C/NOFS... more DC electric fields and associated E × B plasma drifts detected with the double-probe experiment on the C/NOFS satellite during extreme solar minimum conditions near the June 2008 solstice are shown to be highly variable, with weak to moderate ambient amplitudes of ∼1–2 mV/m (∼25–50 m/s). Average field or drift patterns show similarities to those reported for more active solar conditions, i.e., eastward and outward during day and westward and inward at night. However, these patterns vary significantly with longitude and are not always present. Daytime vertical drifts near the magnetic equator are largest in the prenoon sector. Observations of weak to nonexistent prereversal enhancements in the vertical drifts near sunset are attributable to reduced dynamo activity during solar minimum as well as seasonal effects. Enhanced meridional drifts are observed near sunrise in certain longitude regions, precisely where the enhanced eastward flow that persisted from earlier local times terminates. The nightside ionosphere is characterized by larger-amplitude, structured electric fields dominated by horizontal scales of 500–1500 km even where local plasma densities appear relatively undisturbed. Data acquired during successive orbits indicate that plasma drifts and densities are persistently organized by longitude. The high duty cycle of the C/NOFS observations and its unique orbit promise to expose new physics of the low-latitude ionosphere.

First-order thermal correction to the quadratic response tensor and rate for second harmonic plasma emission

by Brett Layden

Thermal Correction to the Rate of Second Harmonic Plasma Emission

by Brett Layden

Bifurcation of Drift Shells Near the Dayside Magnetopause

by Kaan Öztürk

M. Kaan Ozturk and R. A. Wolf
JOURNAL OF GEOPHYSICAL RESEARCH, VOL. 112, A07207, doi:10.1029/2006JA012102, 2007

Close to the dayside magnetopause, there is a region of space where each field line has two magnetic field minima, one... more Close to the dayside magnetopause, there is a region of space where each field line has two magnetic field minima, one near each cusp. That region is located around local noon, and extends about 1–2 Re from the magnetopause. Particles that enter this region with equatorial pitch angles sufficiently close to 90° will cross the dayside not along an equatorial path, but along one of the two branches on either side of the equatorial plane. The two branches are joined again past local noon. This process of drift-shell bifurcation (DSB) is nonadiabatic even under static conditions. Two physical mechanisms can cause this nonadiabaticity: one that is operative for nearly all magnetospheric magnetic field configurations and another that depends on a particular combination of north-south and east-west asymmetry in the magnetic field. This paper deals only with the first mechanism. For configurations with north-south and east-west symmetry, DSB changes the second invariant I of the motion by a small amount that is of the order of the gyroradius (the first invariant is intact). For near-equatorial particles (I % 0) the change can be significantly larger. Assuming north-south and dawn-dusk symmetry, we present
general theoretical expressions for the second-invariant jump DI, which can be applied to a variety of magnetic field models. The results show that DI is sensitively dependent on the bounce phase of the particle at the bifurcation line. The RMS value of DI over a bounce-phase ensemble increases with decreasing mirror field and with increasing kinetic energy. We verify these results with test-particle simulations using model magnetic fields.