Diagnostics of electron cyclotron instabilities of highly charged plasmas by bremsstrahlung and electron spectroscopy


Main funder


Funds granted by main funder (€)

3 500,00


Funding program

Researcher mobility Funding, AoF (Academy of Finland)


Project timetable

Project start date: 01/02/2017

Project end date: 31/12/2018


Summary

Electron cyclotron resonance ion sources (ECRIS) are widely used in accelerator based nuclear and material physics for the production of highly charged ion beams. The performance of an ECRIS is traditionally quantified by measuring the beam current and quality of the extracted ion beams of different charge state ions. The stability of the extracted ion beam currents has drawn more attention recently as the technology is pushing its limits towards higher ion charge states and beam intensities. The stability of the ion beam is important for high power accelerator applications, medical applications such as carbon therapy and industrial applications such as electronic component testing, for example. The experimental study proposed in this research plan focuses on diagnostics of fast plasma oscillations driven by electron cyclotron plasma instabilities. Studying the electron dynamics related to kinetic instabilities in ECR-heated, highly charged plasmas, can be considered as basic research with great significance to applications.

It has been found that ECRIS plasmas are prone to kinetic instabilities due to anisotropy of the electron energy distribution function. The observed plasma instabilities of kinetic origin are associated with strong microwave emission and a burst of energetic electrons escaping the plasma, and explain the periodic oscillations of the extracted beam currents observed in several laboratories. It has been found that the effects of the plasma instabilities can be mitigated by so-called double frequency heating but the exact mechanism for the damping of the plasma waves is unknown. The diagnostics methods developed for this project include bremsstrahlung and electron spectroscopy yielding information on electron losses associated to the kinetic instabilities of ECRIS plasmas. Connecting electron losses to the energy spread of the extracted ion beams could shed light on the ion dynamics in ECRIS plasmas and help explaining the double frequency heating effect. The work will be conducted in collabration between University of Jyväskylä and Institute of Applied Physics, Russian Academy of Sciences.


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Last updated on 2019-07-10 at 07:54