Nonmonoenergetic Beam With Helical Cerenkov Radiation: Possible Technique toDetermine Magnetic Field in a Hostile Electromagnetic Environment

摘要

Modifications caused by the nonmonoenergetic beams to the recently describedhelical Carenkov radiation (resulting from electron helical motion in a medium under the influence of magnetic field) are studied in a visible portion of the spectrum. The analysis is greatly simplified by utilizing a new analytical approximate expression for the number of emitted photons per unit path length for the usual 'monoenergetic' helical Carcknov radiator. The effect of the nonmonoenergetic beam is that simultaneously with the helical Carenkov radiation also the radiation into harmonics (above and below the helical Carenkov effect threshold) may occur at the same radiation angle and at the same visible frequency. Hence, harmonic radiators may enhance the usual helical Carenkov radiation. For the medium of silica aerogel with the index of refraction of 1.075 and the beam energy in the 2-3-MeV range interacting with the magnetic field of about 10 T, one estimates that in the visible portion of the spectrum an electron from a noumonoenergetic beam will generate between 1 and 2 photons at the end of the 10cm interaction length. This shows the possibility of detecting a magnetic field coming from an electromagnetic treat wave form, which in turn, represents a hostile electromagnetic environmental The importance of detecting this magnetic field comes from the fact that in an environmental medium it can disrupt optical signals. Here we show the way for measuring and quantifying such disruptions. (AN).