The paper "The Fokker-Planck Equation for an Inverse-Square Force" by Marshall N. Rosenbluth, William M. MacDonald, and David L. Judd, published in 1956, investigates the contribution to the Fokker-Planck equation for the distribution function of gases due to particle-particle interactions obeying an inverse-square law. The authors derive the coefficients $\langle \Delta v \rangle$ and $\langle \Delta v \Delta v \rangle$ using collision cross sections and express them in terms of two fundamental integrals dependent on the distribution function. They transform the equation to polar coordinates in axial symmetry and expand the distribution function in Legendre functions, leading to a set of one-dimensional coupled nonlinear integro-differential equations. The paper also discusses the simplifications for specific cases, such as those by Chandrasekhar and Spitzer, and provides a method for numerical treatment using electronic computers. The work is sponsored by the U.S. Atomic Energy Commission and published by the University of California Radiation Laboratory.The paper "The Fokker-Planck Equation for an Inverse-Square Force" by Marshall N. Rosenbluth, William M. MacDonald, and David L. Judd, published in 1956, investigates the contribution to the Fokker-Planck equation for the distribution function of gases due to particle-particle interactions obeying an inverse-square law. The authors derive the coefficients $\langle \Delta v \rangle$ and $\langle \Delta v \Delta v \rangle$ using collision cross sections and express them in terms of two fundamental integrals dependent on the distribution function. They transform the equation to polar coordinates in axial symmetry and expand the distribution function in Legendre functions, leading to a set of one-dimensional coupled nonlinear integro-differential equations. The paper also discusses the simplifications for specific cases, such as those by Chandrasekhar and Spitzer, and provides a method for numerical treatment using electronic computers. The work is sponsored by the U.S. Atomic Energy Commission and published by the University of California Radiation Laboratory.