An Electron Density Model of the D‐ and E‐region Ionosphere for Transionospheric VLF Propagation

2021 ◽  
Author(s):  
Wei Xu ◽  
Robert A. Marshall ◽  
Jacob Bortnik ◽  
John W. Bonnell
Keyword(s):  
Electron Density ◽  
Density Model ◽  
E Region ◽  
Vlf Propagation

scholarly journals Survey of electron density changes in the daytime ionosphere over the Arecibo observatory due to lightning and solar flares

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Caitano L. da Silva ◽  
Sophia D. Salazar ◽  
Christiano G. M. Brum ◽  
Pedrina Terra
Keyword(s):  
Electron Density ◽  
Solar Flares ◽  
Low Frequency ◽  
Lower Ionosphere ◽  
Weather Conditions ◽  
Optical Observations ◽  
Radio Waves ◽  
D Region ◽  
E Region ◽  
Arecibo Observatory

AbstractOptical observations of transient luminous events and remote-sensing of the lower ionosphere with low-frequency radio waves have demonstrated that thunderstorms and lightning can have substantial impacts in the nighttime ionospheric D region. However, it remains a challenge to quantify such effects in the daytime lower ionosphere. The wealth of electron density data acquired over the years by the Arecibo Observatory incoherent scatter radar (ISR) with high vertical spatial resolution (300-m in the present study), combined with its tropical location in a region of high lightning activity, indicate a potentially transformative pathway to address this issue. Through a systematic survey, we show that daytime sudden electron density changes registered by Arecibo’s ISR during thunderstorm times are on average different than the ones happening during fair weather conditions (driven by other external factors). These changes typically correspond to electron density depletions in the D and E region. The survey also shows that these disturbances are different than the ones associated with solar flares, which tend to have longer duration and most often correspond to an increase in the local electron density content.

scholarly journals Galactic structure and turbulence, pulsar distances, and the intergalactic medium

2012 ◽  
Vol 8 (S291) ◽  
pp. 211-216 ◽  
Author(s):  
J. M. Cordes
Keyword(s):  
Electron Density ◽  
Intergalactic Medium ◽  
Galactic Structure ◽  
Density Model ◽  
Radio Bursts ◽  
Radio Waves ◽  
Next Generation ◽  
Scattering Measurements ◽  
Galactic Model ◽  
Multi Wavelength

AbstractThis paper summarizes how multi-wavelength measurements will be aggregated to determine Galactic structure in the interstellar medium (ISM) and produce the next-generation electron density model. Fluctuations in density and magnetic field from parsec scales down to about 1000 km cause a number of propagation effects in both radio waves and cosmic rays. Density microstructure appears to include Kolmogorov-like turbulence. The next generation electron-density model, NE2012, will include about double the number of lines of sight with dispersion and scattering measurements and it will be anchored with a much larger number of pulsar parallax distances. The foreground Galactic model is crucial for inferring similar ionized structures in the intergalactic medium (IGM) from scattering measurements on high-z objects. Intergalactic scattering is discussed with reference to distant sources of radio bursts. In particular, the cosmological radio scattering horizon is defined along with its analog for the ISM.

scholarly journals Vertical and longitudinal electron density structures of equatorial E- and F-regions

2011 ◽  
Vol 29 (1) ◽  
pp. 81-89 ◽  
Author(s):  
P. S. Brahmanandam ◽  
Y.-H. Chu ◽  
K.-H. Wu ◽  
H.-P. Hsia ◽  
C.-L. Su ◽  
...  
Keyword(s):  
Electron Density ◽  
Phase Relation ◽  
F Region ◽  
Good Consistency ◽  
June Solstice ◽  
December Solstice ◽  
Different Seasons ◽  
E Region ◽  
First Time ◽  
Longitudinal Structures

Abstract. From global soundings of ionospheric electron density made with FORMOSAT 3/COSMIC satellites for September 2006–August 2009, day-night variations in vertical and longitudinal structures of the electron densities in equatorial E- and F-regions for different seasons are investigated for the first time. The results reveal that the wavenumber-3 and wavenumber-4 patterns dominated the nighttime (22:00–04:00 LT) F-region longitudinal structures in solstice and in equinox seasons, respectively. In daytime (08:00–18:00 LT) F-region, the wavenumber-4 patterns governed the longitudinal structures in the September equinox and December solstice, and wavenumber-3 in March equinox and June solstice respectively. A comparison of the daytime and nighttime longitudinal electron density structures indicates that they are approximately 180° out of phase with each other. It is believed that this out of phase relation is very likely the result of the opposite phase relation between daytime and nighttime nonmigrating diurnal tidal winds that modulate background E-region dynamo electric field at different places, leading to the day-night change in the locations of the equatorial plasma fountains that are responsible for the formation of the F-region longitudinal structures. Further, a good consistency between the locations of the density structures in the same seasons of the different years for both daytime and nighttime epochs has been noticed indicating that the source mechanism for these structures could be the same.

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