Some general questions of fast-electron transport

An inverse problem of fast-electron transport in a dielectric is proposed. This problem consists of determining the field distribution in the dielectric from the measured variations of functionals caused by an electric field within the dielectric. A method for solving the inverse problem on the basis of the general theory of variations in transport functionals is examined. It is shown that the distribution of the information functionals throughout the sample is required in order to determine the appropriate set of sources and functionals. The condition for the independence of the information functionals is obtained. It is also shown that if the variations of the transport functionals are measured and if the information functionals are known, the inverse problem of determining the field distribution reduces to the solution of a system of algebraic equations. Equations are derived for determining the value of the information required to calculate the information functionals.Translated from Izvestiya VUZ. Fizika, No. 6, pp. 25–29, June, 1973.