Radio astronomy began in 1933 when an engineer named Karl Jansky accidentally discovered that radio waves come not just from inventions we create but also from natural stuff in space. Since then, astronomers have built better and better telescopes to find these cosmic radio waves and learn more about where they come from and what they can tell us about the universe. While scientists can learn a...

Introduction: The continuous rapid growth of the telecommunications industry and common application of cell phones have raised debates on the human health risks associated with exposure to radio frequency fields due to these phones or their base stations and other sources such as radar, radio/television waves, and industrial and medical applications. This study aimed to invest...

I consider the prospect to use the outer layer of the Moon as a detector volume for ultra–high energy (UHE) neutrino fluxes and the flux of the lightest neutralino which I assume is the lightest supersymmetric particle (LSP). For this purpose, I calculate the event rates of these fluxes for top–down scenarios. I show that a suitable experiment for the detection of radio waves might be able to d...

あらまし 電波伝搬特性を活用して秘密情報を送受信間で他者に知られることなく伝送・共有する技術につい て,特に電波伝搬の観点から述べる.まず最初に,将来のユビキタスネットワークにおける本技術の位置付けに ついて示す.次に,秘密情報の伝送・共有に電波伝搬特性を活用する方式の基本原理を示す.また,情報理論の 情報量の概念を用いてこの手法の特性を明らかにする.そして,これまで既に研究が行われている電波伝搬特性 に基づいて通信を暗号化するための暗号鍵を生成する方法について紹介する.その実現例の原理を示し,具体的 な秘密情報伝送・共有の特性について明らかにする.このような電波伝搬特性を活用した秘密情報伝送・共有技 術に対しては,他者からの情報盗聴の試み(アタック)に対する耐性が重要となる.このようなアタックについ て電波伝搬的な手法の一例を示し,その実現可能性及び推定性能について示す.最後に,電...

We present a model for microstructure in pulsar radio emission. We propose that micropulses result from the alteration of the radio wave generation region by nearly transverse drift waves propagating across the pulsar magnetic field and encircling the bundle of the open magnetic field lines. It is demonstrated that such waves can modify significantly curvature of these dipolar field lines. This...

Introduction This paper will discuss many of the theoretical and physical principles that underlie the operation of radar systems. The word radar is derived from an acronym for radio detection and ranging. Radar is an electronic and electromagnetic system that uses radio waves to detect and locate objects. Radar operates by transmitting a particular kind of radio frequency waveform and detectin...

Formation of giant radio pulses is attributed to propagation effects in the plasma of pulsar magnetosphere. Induced scattering of radio waves by the plasma particles is found to lead to an efficient redistribution of the radio emission in frequency. With the steep spectrum of pulsar radiation, intensity transfer between the widely spaced frequencies may imply significant narrow-band amplificati...

We report the peculiar interaction of two type III bursts observed in the solar wind. As electron beams propagating on the same magnetic field lines cross, a spectacular depletion of the type III radio emission is observed. We combine observations from the WAVES experiment on board the STEREO mission together with kinetic plasma simulations to study the extinction of type III radio emission res...

The radio/optical alignment effect for small powerful radio galaxies has been shown to be produced by shock waves formed by the interaction of the head of the jet and/or cocoon with clouds embedded in the interstellar/intergalactic medium. We present here preliminary results of analytical and numerical solutions that have been made to account for the production of implosive shock waves induced ...