Abstract
A method is proposed for tomography of the distribution function of energetic ions that are adiabatically trapped in an open magnetic trap, according to the diagnostic data by the method of collective Thomson scattering. This method is based on measurements of the scattering spectra from successive plasma cross sections corresponding to different values of the magnetic-field strength along a single line of force. It is shown that the problem of restoring the ion distribution function in the velocity space from the measurement data in this situation is reduced to an integral equation of the first kind that allows an analytical solution. Several ways to construct exact and approximate solutions of the resulting integral equation are considered.
Highlights
Scattering of high-power probing millimeter radiation by thermal fluctuations of magnetically active plasma allows one to obtain information on the velocity distribution of plasma ions with good spatial and time resolutions [1]
An important possibility for diagnosing the distribution function of energetic ions is the implementation of the method for recording the spectra of collective Thomson scattering, which was tested in toroidal magnetic traps [22], in an open magnetic trap
Following paper [22], we note the main features of the collective Thomson scattering in plasma of a largescale open magnetic trap using the example of the largest such GDT installation that currently operates at the Budker Institute of Nuclear Physics (Siberian Branch, Russian Academy of Sciences)
Summary
Scattering of high-power probing millimeter radiation by thermal fluctuations of magnetically active plasma (the so-called collective Thomson scattering) allows one to obtain information on the velocity distribution of plasma ions with good spatial and time resolutions [1]. Following paper [22], we note the main features of the collective Thomson scattering in plasma of a largescale open magnetic trap using the example of the largest such GDT (gas-dynamic trap) installation that currently operates at the Budker Institute of Nuclear Physics (Siberian Branch, Russian Academy of Sciences) In this setup, plasma is divided into two fractions: background plasma that is confined in the gasdynamic regime and high-energy ions resulting from the bombardment of the background plasma by beams of neutral atoms with energies of 20–30 keV [23]. Measuring the scattered-signal spectrum at a given scattering angle does not allow one to restore the full distribution function f (v||,v⊥), but such a restoration is possible in principle using the two-dimensional function F (u,θ), i.e., if we perform measurements for a certain set of scattering angles This approach to the recovery of the distribution function is close to the classical tomography problem, which can be solved in this case via standard mathematical methods for solving ill-posed inverse problems. We mathematically formulate the problem of such a recovery, show that such a problem can be reduced to finding solutions to an integral equation of the first kind, and demonstrate ways to solve this equation
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
