Whistler excitation by electron beams in laboratory plasmas

Short-wavelength quasielectrostatic waves radiated by a small probe in a cold $({T}_{e}\ensuremath{\approx}0.5\phantom{\rule{0.3em}{0ex}}\mathrm{eV})$ laboratory magnetoplasma are studied in both the upper-hybrid (UH) and the lower-hybrid (LH) frequency ranges. Measured radiation patterns are characterized by resonance cones in the LH range and in the low-frequency part of the UH range (at $\ensuremath{\omega}l2{\ensuremath{\omega}}_{c}$), while in its high-frequency part (at $\ensuremath{\omega}g2{\ensuremath{\omega}}_{c}$), a beamed radiation along the external magnetic field is observed. An analysis reveals that the angular resonance is primarily limited by the phase effects caused by weak spatial dispersion.

Excitation of quasielectrostatic waves in a laboratory magnetoplasma with weak spatial dispersion.

Transition radiation from the zone of injection of a modulated electron beam spiralling into a magnetoplasma has been identified as whistler waves propagating quasiparallel to the external magnetic field. The characteristics of the radiation are similar to the emission by localized sources, such as loop antennas and electric dipoles: resonance-cone structures at low plasma densities and energy flow along the external magnetic field at higher densities, with a diverging radiation pattern and with whistler phase velocities inversely proportional to the plasma frequency. These studies should contribute to a wider understanding of the physical processes connected with the injection of charges in a magnetoplasma – either from a gun on board a spacecraft or in a plasma chamber – and thus allow the determination of appropriate radiator characteristics in order to control, to some extent, plasma perturbations and wave emission in the region of the injector.

Whistler emission through transition radiation by a modulated electron beam spiralling in a magnetoplasma

The paper studies the electromagnetic wave radiation by a density modulated and thin electron beam of finite length injected obliquely with respect to the constant external magnetic field into a cylindrical plasma column embedded in a homogeneous medium (plasma, dielectric, or free space) and aligned along the magnetic field lines The time-averaged power radiated at the modulation frequency is determined as a function of the beam, the plasma column, and the medium parameters Particular attention is devoted to the case when the beam modulation frequency belongs to the whistler frequency band The paper shows what significant differences exist between the physical features of the emissions when the beam radiates in a plasma column embedded in a homogeneous medium or in a uniform and unbounded magnetized plasma Based on the results of numerical calculations, the time-averaged power radiated by pulsed and modulated beams has been estimated for typical laboratory plasma experiments In particular, it is shown that a beam propagating in a plasma column can efficiently enhance its wave emission due to Cherenkov and normal cyclotron excitation of guided whistler modes

Electromagnetic wave radiation by an electron beam spiraling in a magnetized plasma column

We present the results of laboratory experiments in which the mechanisms of interaction of electron beams with whistler waves in a magnetoplasma are studied. Different mechanisms of whistler generation during the injection of a modulated electron beam in the plasma are studied, and the mechanism of conversion of the beam kinetic energy to radiation is demonstrated. The processes of whistler wave generation by the modulated beam at the ˇ Cerenkov and Doppler resonances are analyzed in detail. The excitation of whistler waves by means of a nonresonant mechanism of the transition radiation is studied.

Laboratory modeling of the interaction of electron beams with a magnetoplasma

In the frame of laboratory studies devoted to whistler excitation by a modulated electron beam injected in a magnetoplasma under conditions relevant to space experiments, fast processes have been investigated using the modulated electron beam as a train of short-time current pulses injected in the plasma Single pulses of duration of the order of τ≃15 ns as well as unmodulated beams with sharp fronts (step functions with rise time of the order of τ≃10 ns) have been injected in the afterglow plasma with an energy of the order of 300 eV Plasma responses to the fast perturbations are transported by whistler waves in the frequency range ωlh≪1/τ<ωc<ωp Different types of responses have been evidenced and characterized, depending on the nature of the whistler excitation mechanism involved: Nonresonant transition radiation from the beam injection point and Cherenkov resonant emission Both emissions could be distinguished one from each other owing to adequate choices of plasma parameters and observation conditi

Whistler excitation by short current pulses in a magnetoplasma

Handle everyday research tasks with reliable, citation-backed results

Your personal Research Agent to handle research tasks with citation-backed results

Popular Tasks used by Researchers

How can I help with your research?

Meet SciSpace

Get more enhanced response by uploading the PDFs you want me to reference.

No relevant PDFs in your library

SciSpace is the AI research assistant for academics. Run systematic literature reviews on 280M+ papers, and write papers with cited sources. Trusted by 1M+ students, PhDs & researchers.

SciSpace | AI for Research

Analyze PDFs

Code & Manuscripts

Funding & Grants

Literature & Patents

Medical & Clinical Data

Systematic Review

Visualize & Present

Web & Data

Build a Google Scholar-like website for your research.

Build a website

Create charts and images for your research

Create a Chart

Write a paper for submission to a journal

Draft a manuscript

Patent Search

Design eye-catching scientific posters in minutes.

Scientific Poster Generation

Systematic Literature Review

One task is running at the moment. Your messages will be shown right after.

Drag and drop or click here to browse

Loved by <highlight>1 million+</highlight> researchers

Extract a list of specific topics and their sources from unstructured text

Topics

Compare and analyze relevant papers that matches with your search

Papers

Get insights from PDFs and bookmarked papers from your library

My library

Recent searches

Try searching for:

Catch AI-generated content in scholarly and non-scholarly content

{ai} Detector

Ai Writer

Get PDF Summaries, highlighted text explanations 

Chat with PDF

Effortlessly create in-text citations and bibliographies in APA and 2,500 other formats

Citation generator

Get explanations, summaries, and answers on academic papers

Ease up your research workflow with {scispace}'s cohort of exciting AI tools

Elevate your academic writing skills and convey your ideas the way you want

Paraphraser

Explore our range of reading and writing tools

Your file is being prepared and should be ready in a few minutes. If it's a large file, it might take a bit longer. You can close this window, and we'll email you the file when it's done.

You have reached a maximum limit of <strong>{limit}</strong> columns in the table. Remove at least <strong>1</strong> column to add or create another one.

C. Krafft

Author Tools

Chat about Author

Papers

Whistler excitation by short current pulses in a magnetoplasma