Estimation method for electron-hole pair density in plasma columns

A simple method to estimate the electron-hole pair density in plasma column s created by heavy ions is described. The volume of plasma column is descri bed in a ratio to the one of cone with the same range and bottom radius of the plasma column. The volume ratio is expressed by second polynomials of t he energy per unit mass of the heavy ion. With three parameters of the seco nd polynomials, the range and the bottom radius of the cone, the volume of the corresponding plasma column, and consequently, the electron-hole pair d ensity inside it are easily estimated. (C) 1999 American Institute of Physi cs. [S0034-6748(99)03811-3].