Auroral kilometric radiation (AKR) is the paradigm of intense radio emission from planetary magnetospheres. Being close to electron gyro frequency and/or its lower harmonics, observation indicates non-thermal state source plasma. Emission produced when plasma enters a energetic excitation which results in deformation distribution function. Under certain conditions this leads "quasi-coherent" em...

Recent measurements of a 2D electron gas subjected to microwave radiation reveal a magnetoresistance with an oscillatory dependence on the ratio of radiation frequency to cyclotron frequency. We perform a diagrammatic calculation and find radiation-induced resistivity oscillations with the correct period and phase. Results are explained via a simple picture of current induced by photoexcited di...

Cyclotron harmonic interactions are a key physics issue of critical importance to the generation of terahertz radiation via the electron cyclotron maser instability for practical magnetic field strengths. We present an inherent mechanism, as well as a deciding factor, which governs the competition between low- and high-harmonic interactions. Multimode simulations reveal the physical process in ...

The spectrum of cyclotron radiation is calculated for anisotropically distributed relativistic electrons with a nonrelativistic velocity scattering across the magnetic field. It is shown that if such electrons are responsible for a formation of the ”cyclotron” line in the spectrum of Her X-1, then the value of its magnetic field (3 − 6) · 10 Gs following from this interpretation is in a good ag...

An electron beam passing through a metamaterial structure is predicted to generate reversed Cherenkov radiation, an unusual and potentially very useful property. We present an experimental test of this phenomenon using an intense electron beam passing through a metamaterial loaded waveguide. Power levels of up to 5 MW are observed in backward wave modes at a frequency of 2.40 GHz using a one mi...

We present Spitzer Infrared Spectrograph (IRS) observations of eleven intermediate polars (IPs). Spectra covering the wavelength range from 5.2 to 14 μm are presented for all eleven objects, and longer wavelength spectra are presented for three objects (AE Aqr, EX Hya, and V1223 Sgr). We also present new, moderate resolution (R ∼ 2000) near-infrared spectra for five of the program objects. We f...

Ultrashort pulses of intense, coherent, and tunable far-infrared (FIR) and mid-infrared (MIR) radiation, achievable with freeelectron lasers (FELs) and optical parametric amplifiers (OPAs), provide unique opportunities to investigate low energy dynamics in solids. This paper reviews our recent experiments on bulk and quantum-confined semiconductors using such radiation. These experiments includ...

As an important plasma wave mode in the geospace, magnetosonic waves can interact with both radiation belt electrons and protons, thereby impacting the dynamics of magnetospheric particles. Based on the Doppler-shifted resonance condition and the cold plasma dispersion relation, we investigate the profiles of resonance zone and resonant frequency of the Landau resonance between radiation belt e...

Schönherr, Gabriele Strong magnetic fields of accreting neutron stars — Modeling cyclotron lines — Accreting neutron stars in X-ray binaries are unique astrophysical laboratories for studying the physics of matter under extreme conditions. Not only does their compact nature lead to an amount of gravity only topped by black hole systems; they can also possess extreme magnetic fields, exceeding t...