helicopter-borne electromagnetic (hem) is a fast and high resolution airborne electromagnetic (aem) method that is frequently used for imaging of the subsurface resistivity structures. this is a versatile and cost effective method, frequently has used in mineral and groundwater exploration and various environmental problems. modern frequency-domain hem systems utilize small electromagnetic, mag...

ABSTRACT The highly tangled magnetic field of a magnetar supports shear waves similar to Alfvén in an ordered field. Here, we explore if torsional modes excited the stellar interior and magnetosphere can explain quasi-periodic oscillations (QPOs) observed tail giant flare SGR 1900+14. We solve initial value problem for that couples relativistic magnetosphere. Assuming arise from sudden release ...

This paper is concerned with the surface and small scale effects on transverse vibration of a viscoelastic single-layered graphene sheet (SLGS) subjected to an in-plane magnetic field. The SLGS is surrounded by an elastic medium which is simulated as Visco-Pasternak foundation. In order to investigate the small scale effects, the nonlocal elasticity theory is employed due to its simplicity and ...

If an attempt is made to produce an artificial aurora by ejecting a beam of electrons from a satellite, the experiment will be jeopardized if the satellite potential becomes so high as to prevent the escape of the beam electrons. The buildup of potential depends on the current collection properties of the satellite. The theoretical problem considered is that of the collection of electrons by a ...

[1] Strong electron heating by the injection of highly powerfu l HF waves can lead to the format ion of ionospheric plasma density perturbations that stretch along the magnetic field lines. Those density perturbations can serve as ducts for guiding natural and artificial ELF/VLF waves. This paper presents a theoretical model of duct formation due to HF heating of the ionosphere. The model is ba...

[1] In this work, the magnetic variations simulated by the NCAR thermosphereionosphere-electrodynamics general circulation model (TIE-GCM) in the vicinity of the magnetic equator are examined to evaluate the ability of this model to reproduce the major features of the equatorial electrojet (EEJ) as observed on the ground as well as on board low-altitude orbiting satellites. The TIE-GCM simulate...

[1] We have recently extended the global magnetohydrodynamic (MHD) model BATS-R-US to account for pressure anisotropy. Since the inner magnetosphere dynamics cannot be fully described even by anisotropic MHD, we coupled our anisotropic MHD model with two inner magnetospheric models: the Rice Convection Model (RCM) and the Comprehensive Ring Current Model (CRCM). The coupled models provide bette...

One of the interesting observations from the FAST satellite is the detection of strong spiky waveforms in the parallel electric field in association with ion cyclotron oscillations in the perpendicular electric fields. We report here an analytical model of the coupled nonlinear ion cyclotron and ion-acoustic waves, which could explain the observations. Using the fluid equations for the plasma c...