A payload for the study of electric fields and electron density in the equatorial region

1982 ◽  
Vol 2 (7) ◽  
pp. 57-59 ◽  
Author(s):  
S. Pal ◽  
S. Prakash ◽  
Y.B. Acharya ◽  
R.N. Misra
Keyword(s):  
Electron Density ◽  
Electric Fields ◽  
Equatorial Region

scholarly journals Simulation of mode conversion process from upper-hybrid waves to LO-mode waves in the vicinity of the plasmapause

2010 ◽  
Vol 28 (6) ◽  
pp. 1289-1297 ◽  
Author(s):  
M. J. Kalaee ◽  
Y. Katoh ◽  
A. Kumamoto ◽  
T. Ono ◽  
Y. Nishimura
Keyword(s):  
Density Gradient ◽  
Electric Fields ◽  
Numerical Experiments ◽  
Mode Conversion ◽  
Equatorial Region ◽  
Magnetized Plasma ◽  
Conversion Process ◽  
Observation Data ◽  
Linear Mode ◽  
Wave Normal

Abstract. In order to clarify the role of the mode conversion process in the generation mechanism of LO-mode waves in the equatorial region of the plasmasphere, we have investigated the linear mode conversion process among upper-hybrid-resonance (UHR)-mode, Z-mode and LO-mode waves by a numerical simulation solving Maxwell's equations and the equation of motion of a cold electron fluid. The wave coupling process occurring in the cold magnetized plasma are examined in detail. In order to give a realistic initial plasma condition in the numerical experiments, we use initial parameters inferred from observation data obtained around the generation region of LO-mode waves obtained by the Akebono satellite. A density gradient is estimated from the observed UHR frequency, and wave normal angles are estimated from the dispersion relation of cold plasma by comparing observed wave electric fields. Then, we perform numerical experiments of mode conversion processes using the density gradient of background plasma and the wave normal angle of incident upper hybrid mode waves determined from the observation results. We found that the characteristics of reproduced LO-mode waves in each simulation run are consistent with observations.

Revisiting Local Electric Fields on Close-Packed Metal Surfaces: Theory Versus Experiments

2007 ◽  
Vol 128 ◽  
pp. 219-224 ◽  
Author(s):  
P.P. Kostrobiy ◽  
Bogdan M. Markovych ◽  
Yuri Suchorski
Keyword(s):  
Electron Density ◽  
Electric Fields ◽  
Metal Surfaces ◽  
Integration Method ◽  
Functional Integration ◽  
Correlation Effects ◽  
Flat Surfaces ◽  
Exchange Correlation ◽  
Density Distributions ◽  
Theory Versus

An external electrostatic field of the order of a few tens of a volt per nanometer causes significant changes in the electron density distribution near a metal surface. Because of differing electronic distributions and varying responses of electrons to the applied field for various metals, the resulting local field distribution in the close vicinity of the surface should depend on the electronic properties of the particular metal, even for flat surfaces. Field-free and field-modified electron density distributions for different metal surfaces were calculated using the functional integration method. This approach enables the exchange-correlation effects to be correctly considered and makes it possible to account for the proper field-effect for broad field ranges without using the perturbation theory. The results of calculations are compared with the field-ion microscopic observations.

The effect of disturbed-time electric fields on the inner plasmasphere

1994 ◽  
Vol 12 (4) ◽  
pp. 296-303 ◽  
Author(s):  
H. F. Balmforth ◽  
R. J. Moffett ◽  
A. J. Smith ◽  
G. J. Bailey
Keyword(s):  
Mathematical Model ◽  
Electric Field ◽  
Electron Density ◽  
Electric Fields ◽  
Doppler Shift ◽  
Group Delay ◽  
Whistler Mode ◽  
L Value

Abstract. Results from a mathematical model provide a description of the mid-latitude, low L-shell ionosphere and plasmasphere. Variations in the composition and dynamics of the plasmasphere and changes in the nature of the coupling between the plasmasphere and the ionosphere are studied for moderately disturbed conditions. Modelled results are compared to group delay and Doppler shift measurements of whistler mode signals at Faraday, Antarctica (L ≈ 2.5), to investigate the effects of disturbed time electric fields on the inner plasmasphere and ionosphere. The disturbed time electric field causes a rapid outward drifting of the plasma leading to a decrease in modelled plasmaspheric electron density at a fixed L-value, which agrees with experimental observations. During the periods of outward drift, the modelled coupling flux is upwards to the plasmasphere which can lead to a significant depletion of NmF2 values.

scholarly journals Heterogeneous Intramolecular Electric Field as a Descriptor of Diels-Alder Reactivity

2020 ◽  
Author(s):  
Matthew Hennefarth ◽  
Anastassia N. Alexandrova
Keyword(s):  
Electric Field ◽  
Electron Density ◽  
Electric Fields ◽  
Alder Reaction ◽  
Diels Alder ◽  
Charge Movement ◽  
External Electric Fields ◽  
Topological Features ◽  
Diels Alder Reaction ◽  
Kinetics Of

<div> <div> <div> <p>External electric fields have proven to be an effective tool in catalysis, on par with pressure and temperature, affecting the thermodynamics and kinetics of a reaction. However, fields in molecules are complicated heterogeneous vector objects, and there is no universal recipe for grasping the exact features of these fields that implicate reactivity. Herein, we demonstrate that topological features of the heterogeneous electric field within the reactant state, as well as of the quantum mechanical electron density – a scalar reporter on the field experienced by the system – can be identified as rigorous descriptors of the reactivity to follow. We scrutinize specifically the Diels-Alder reaction. Its 3-D nature and the lack of a singular directionality of charge movement upon barrier crossing makes the effect of the electric field not obvious. We show that the electric field topology around the dienophile double bond, and the associated changes in the topology of the electron density in this bond are predictors of the reaction barrier. They are also the metrics by which to rationalize and predict how the external field would inhibit or enhance the reaction. The findings pave the way toward designing external fields for catalysis, as well as reading the reactivity without an explicit mechanistic interrogation, for a variety of reactions. </p> </div> </div> </div>

scholarly journals Simulation study on parametric dependence of whistler-mode hiss generation in the plasmasphere

2021 ◽  
Vol 73 (1) ◽  
Author(s):  
Yin Liu ◽  
Yoshiharu Omura ◽  
Mitsuru Hikishima
Keyword(s):  
Magnetic Field ◽  
Electron Density ◽  
Nonlinear Process ◽  
Background Field ◽  
Realistic Model ◽  
Equatorial Region ◽  
Generation Process ◽  
Hot Electron ◽  
Wave Growth ◽  
Background Magnetic Field

AbstractWe conduct electromagnetic particle simulations to examine the applicability of nonlinear wave growth theory to the generation process of plasmaspheric hiss. We firstly vary the gradient of the background magnetic field from a realistic model to a rather steep gradient model. Under such variation, the threshold amplitude in the nonlinear theory increases quickly and the overlap between threshold and optimum amplitude disappears correspondingly, the nonlinear process is suppressed. In the simulations, as we enlarge the gradient coefficient of the background magnetic field, waves generated near the equator do not grow through propagation. By examining the range of suitable values of inhomogeneity factor S (i.e., $$|S|<2$$ | S | < 2 ), we find the generation of wave packets is limited to the equatorial region when the background field is steep, showing a good agreement with what is indicated by critical distance in the theory. We then check the dependence of generation of hiss emissions on different hot electron densities. Since the overlap between threshold and optimum amplitude vanishes, the nonlinear process is weakened when hot electron density becomes smaller. In the simulation results, we find similar wave structures in all density cases, yet with different magnitudes. The existence of suitable S values implies that the nonlinear process occurs even at a low level of hot electron density. However, by examining $$J_E$$ J E that closely relates to the wave growth, we find energy conveyed from particles to waves is much limited in small density cases. Therefore, the nonlinear process is suppressed when hot electron density is small, which agrees with the theoretical analysis. Graphical Abstract

scholarly journals EDI convection measurements at 5-6 R<sub>E</sub> in the post-midnight region

1999 ◽  
Vol 17 (12) ◽  
pp. 1503-1512 ◽  
Author(s):  
J. M. Quinn ◽  
G. Paschmann ◽  
N. Sckopke ◽  
V. K. Jordanova ◽  
H. Vaith ◽  
...  
Keyword(s):  
Electric Fields ◽  
Temporal Variations ◽  
Equatorial Region ◽  
Frame Of Reference ◽  
Electron Drift ◽  
Ionospheric Model ◽  
Rotating Frame ◽  
Plasma Convection ◽  
High Data ◽  
Instruments And Techniques

Abstract. We present the first triangulation measurements of electric fields with the electron drift instrument (EDI) on Equator-S. We show results from five high-data-rate passes of the satellite through the near-midnight equatorial region, at geocentric distances of approximately 5–6 RE, during geomagnetically quiet conditions. In a co-rotating frame of reference, the measured electric fields have magnitudes of a few tenths of mV/m, with the E × B drift generally directed sunward but with large variations. Temporal variations of the electric field on time scales of several seconds to minutes are large compared to the average magnitude. Comparisons of the "DC" baseline of the EDI-measured electric fields with the mapped Weimer ionospheric model and the Rowland and Wygant CRRES measurements yield reasonable agreement.Key words. Magnetospheric physics (electric fields; plasma convection; instruments and techniques)

Seismo-ionospheric precursors of the 14 November 2019 M7.1 Indonesia Earthquake detected by FORMOSAT-7/COSMIC-2

2020 ◽  
Author(s):  
Jann-Yenq Liu ◽  
Chi-Yen Lin ◽  
Fu-Yuan Chang ◽  
Yuh-Ing Chen
Keyword(s):  
Electron Density ◽  
Electric Fields ◽  
Radio Occultation ◽  
Electron Content ◽  
Ion Temperature ◽  
Density Profiles ◽  
Ion Density ◽  
Total Electron ◽  
Ion Velocity ◽  
Electron Density Profiles

&lt;p&gt;FORMOSAT-7/COSMIC-2 (F7/C2), with the mission orbit of 550 km altitude, 24-deg inclination, and a period of 97 minutes, was launched on 25 June 2019.&amp;#160; Tri-GNSS Radio occultation System (TGRS), Ion Velocity Meter (IVM), and RF beacon onboard F7/C2 six small satellites allow scientists to observe the plasma structure and dynamics in the mid-latitude, low-latitude, and equatorial ionosphere in detail. &amp;#160;F7/C2 TGRS sounds ionospheric RO (radio occultation) electron density profiles, while F7/C2 IVM probes the ion density, ion temperature, and ion velocity at the satellite altitude.&amp;#160; The F7/C2 electron density profiles and the ion density, ion temperature, and ion velocity, as well as the global ionospheric map (GIM) of the total electron content (TEC) derived from global ground-based GPS receivers are used to detect seismo-ionospheric precursors (SIPs) of the 14 November 2019 M7.1 Indonesia Earthquake.&amp;#160; The GIM TEC and F7/C2 RO NmF2 significantly increase specifically over the epicenter on 25-26 October, which indicates SIPs of the 14 November 2019 M7.1 Indonesia Earthquake being detected.&amp;#160; The F7/C2 RO electron density profiles upward motions suggest that the eastward electric fields have been enhanced during the SIP days of the 2019 M7.1 Indonesia earthquake.&amp;#160; The seismo-generated electric fields of the 2019 M7.1 Indonesia earthquake are 0.34-0.64 mV/m eastward. &amp;#160;The results demonstrate that F7/C2 can be employed to detect SIPs in the ionospheric plasma, which shall shed some light on earthquake prediction/forecast.&lt;/p&gt;

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