Whistler and Alfvén Mode Cyclotron Masers in Space

Abstract

The subject of wave-particle interactions occurring in space plasmas has developed strongly, both observationally and theoretically, since the discovery of the Van Allen radiation belts of energetic charged particles trapped in the Earth's magnetosphere over forty years ago. These wave-particle interactions are recognized today as being a most important research topic in space plasma physics. This book provides a full and systematic description of the physical theory of whistler and Alfvén cyclotron masers acting in planetary magnetospheres, and in the Sun's outer atmosphere. The book introduces research topics by examining significant problems in the subject. It gives sufficient detail on the topic that readers can go on to apply the methods presented to new problems, helping them with their own research. This book is a valuable reference for researchers and graduate students working in space science, solar-terrestrial physics, plasma physics, and planetary sciences.

Space Weather: Physics, Effects and Predictability

“…The local acceleration can be achieved through the resonant wave-particle acceleration between energetic electrons and whistler mode waves (Horne and Thorne 1998;Horne et al 2003aHorne et al , b, 2005Horne et al , 2006Trakhtengerts and Rycroft 2008). Out of the various whistler mode waves present in the magnetosphere, chorus waves are preferred because (a) chorus waves are most intense between L = 4-6 from midnight to the early afternoon MLT sector, corresponding to the peak in the flux density of the outer radiation belt (Meredith et al 2001(Meredith et al , 2003, (b) wave power increases with magnetic activity in a region where the ratio of the electron plasma frequency to the gyrofrequency is low, which is also a condition for the efficient diffusion of electrons to higher energies (Horne et al 2003a), and (c) wave acceleration predicts an energy dependent ''flat top'' pitch angle distribution, which has also been observed during a magnetic storm (Horne et al 2003b).…”

“…Resonant wave-particle interactions also scatter particles into the loss cone (Trakhtengerts and Rycroft 2008), leading the loss of particles from the interaction region into the atmosphere. The waves involved can be plasmaspheric hiss (Abel and Thorne 1998;Meredith et al 2006), electromagnetic ion cyclotron waves (Albert 2003;Summers and Thorne 2003;Glauert and Horne 2005), lightning generated whistlers and whistler mode waves from ground based radio transmitters (Abel and Thorne 1998).…”

“…Some arguments indicate that convection alone can account for the ring current increase (Ebihara and Ejiri 2003), whereas others have concluded that an energization process leading to charged particles with energies exceeding 100 keV needs smaller-scale, time varying electric fields (Ganushkina et al 2005). The theory of wave-particle interactions in the magnetosphere has been reviewed recently by Trakhtengerts and Rycroft (2008). A probabilistic assessment on likely future storm occurrence is one of the top priorities for space weather forecasting (Tsubouchi and Omura 2007).…”

Kinetic instabilities in non-equilibrium plasma: a review of observations

“…The observed in experiments generation of electromagnetic radiation bursts have much in common with the natural sources of coherent cyclotron radiation -the so-called space cyclotron masers defining population energetic particles of the radiation belts, and as well as responsible for the formation of electromagnetic radiation the Earth's magnetosphere in ELF -VLF range, Jovian decametric emission and some types of solar activity. [4,5].In the last decade the interest in this study was renewed due the most powerful digital oscilloscopes with a broad band (up to 60 GHz) and high-speed ADC (up to 160 GS/s), which in real time measure the electric field of the wave. With their help, for the first time we have the opportunity to register with the necessary temporal resolution low-power broadband electromagnetic radiation emerging from the plasma, to determine its dynamic spectrum allocated to the background of strong interference.…”

“…The observed in experiments generation of electromagnetic radiation bursts have much in common with the natural sources of coherent cyclotron radiation -the so-called space cyclotron masers defining population energetic particles of the radiation belts, and as well as responsible for the formation of electromagnetic radiation the Earth's magnetosphere in ELF -VLF range, Jovian decametric emission and some types of solar activity. [4,5].…”