scholarly journals Electromagnetic Monitoring of Italian Volcanoes with the RDF Network, Developed by the Radio Emissions Project

2021 ◽  
Vol 9 (7) ◽  
Author(s):  
Valentino Straser ◽  
Daniele Cataldi ◽  
Gabriele Cataldi ◽  
Giampaolo Gioacchino Giuliani
Keyword(s):  
Radio Emissions ◽  
Electromagnetic Monitoring

Planetary Radio Emissions II

1988 ◽  
Author(s):  
H.O. Rucker ◽  
S.J. Bauer ◽  
B.M. Pedersen
Keyword(s):  
Radio Emissions

Planetary Radio Emissions I

1985 ◽  
Author(s):  
H.O. Rucker ◽  
W.S. Kurth ◽  
G. Mann
Keyword(s):  
Radio Emissions

Planetary Radio Emissions III

1992 ◽  
Author(s):  
H.O. Rucker ◽  
S.J. Bauer ◽  
B.M. Pedersen
Keyword(s):  
Radio Emissions

Planetary Radio Emissions VI

2006 ◽  
Author(s):  
H.O. Rucker ◽  
W.S. Kurth ◽  
G. Mann
Keyword(s):  
Radio Emissions

Sporadic Narrowband Radio Emissions from Uranus

1986 ◽  
Author(s):  
W. S. Kurth ◽  
D. A. Gurnett ◽  
F. L. Scarf
Keyword(s):  
Radio Emissions

scholarly journals The effects of density inhomogeneities on the radio wave emission in electron beam plasmas

2021 ◽  
Vol 87 (2) ◽  
Author(s):  
Xin Yao ◽  
Patricio A. Muñoz ◽  
Jörg Büchner ◽  
Xiaowei Zhou ◽  
Siming Liu
Keyword(s):  
Magnetic Reconnection ◽  
Radio Wave ◽  
Solar Flares ◽  
Electron Beams ◽  
Distribution Functions ◽  
Plasma Emission ◽  
Langmuir Waves ◽  
Radio Emissions ◽  
Density Inhomogeneities ◽  
Effects Of Density

Type III radio bursts are radio emissions associated with solar flares. They are considered to be caused by electron beams travelling from the solar corona to the solar wind. Magnetic reconnection is a possible accelerator of electron beams in the course of solar flares since it causes unstable distribution functions and density inhomogeneities (cavities). The properties of radio emission by electron beams in an inhomogeneous environment are still poorly understood. We capture the nonlinear kinetic plasma processes of the generation of beam-related radio emissions in inhomogeneous plasmas by utilizing fully kinetic particle-in-cell code numerical simulations. Our model takes into account initial electron velocity distribution functions (EVDFs) as they are supposed to be created by magnetic reconnection. We focus our analysis on low-density regions with strong magnetic fields. The assumed EVDFs allow two distinct mechanisms of radio wave emissions: plasma emission due to wave–wave interactions and so-called electron cyclotron maser emission (ECME) due to direct wave–particle interactions. We investigate the effects of density inhomogeneities on the conversion of free energy from the electron beams into the energy of electrostatic and electromagnetic waves via plasma emission and ECME, as well as the frequency shift of electron resonances caused by perpendicular gradients in the beam EVDFs. Our most important finding is that the number of harmonics of Langmuir waves increases due to the presence of density inhomogeneities. The additional harmonics of Langmuir waves are generated by a coalescence of beam-generated Langmuir waves and their harmonics.

scholarly journals Sliding Contacts in Planetary Magnetospheres

Symmetry ◽  
2021 ◽  
Vol 13 (2) ◽  
pp. 283
Author(s):  
Elena Belenkaya ◽  
Igor Alexeev
Keyword(s):  
Large Scale ◽  
Strong Field ◽  
Magnetized Plasma ◽  
Sliding Contacts ◽  
Radio Emissions ◽  
Planetary Magnetospheres ◽  
Current Task ◽  
Surrounding Space ◽  
Non Local ◽  
A Current

In the planetary magnetospheres there are specific places connected with velocity breakdown, reconnection, and dynamo processes. Here we pay attention to sliding layers. Sliding layers are formed in the ionosphere, on separatrix surfaces, at the magnetopauses and boundaries of stellar astrospheres, and at the Alfvén radius in the equatorial magnetosphere of rapidly rotating strongly magnetized giant planets. Although sliding contacts usually occur in thin local layers, their influence on the global structure of the surrounding space is very great. Therefore, they are associated with non-local processes that play a key role on a large scale. There can be an exchange between different forms of energy, a generation of strong field-aligned currents and emissions, and an amplification of magnetic fields. Depending on the conditions in the magnetosphere of the planet/exoplanet and in the flow of magnetized plasma passing it, different numbers of sliding layers with different configurations appear. Some are associated with regions of auroras and possible radio emissions. The search for planetary radio emissions is a current task in the detection of exoplanets.

scholarly journals Wideband Dual-Polarized VHF Antenna for Space Observation Applications

Sensors ◽  
2020 ◽  
Vol 20 (15) ◽  
pp. 4351
Author(s):  
Alexandru Tatomirescu ◽  
Alina Badescu
Keyword(s):  
Radiation Pattern ◽  
Group Delay ◽  
High Gain ◽  
Antenna Element ◽  
Frequency Bandwidth ◽  
Radio Emissions ◽  
Relative Bandwidth ◽  
Pattern Stability ◽  
Dual Polarized ◽  
Delay Variation

This work presents the design for an antenna element that can be used in radio arrays for the monitoring and detecting of radio emissions from cosmic particles’ interactions in the atmosphere. For these applications, the pattern stability over frequency is the primary design goal. The proposed antenna has a high gain over a relative bandwidth of 88%, a beamwidth of 2.13 steradians, a small group delay variation and a very stable radiation pattern across the frequency bandwidth of 110 to 190 MHz. It is dual polarized and has a simple mechanical structure which is easy and inexpensive to manufacture. The measurements show that the ground has insignificant impact on the overall radiation pattern.

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