LAUSR

Several kinds of instabilities are often observed in the solar wind. Langmuir waves have been observed using wideband plasma wave measurements on several spacecrafts such as the Galileo spacecraft. We studied the Langmuir wave instability event in the solar wind on 10 December 1990, during a solar maximum. On this date, highly structured bursts and Langmuir waves have been observed by the Galileo spacecraft. We used the dispersion relation in hot magnetized plasma to calculate the Langmuir wave instability properties. The properties of Langmuir wave instability are investigated and all physical parameters of interplanetary in around 1 AU are analyzed. The instability parameters, such as wave frequency, the thermal velocity and the damping rate are calculated. The results show that the damping rate of Langmuir waves increases with increasing the frequency of Langmuir waves. Also, the lowest damping rate decreases with increase in the wave normal angle. The results show that a good agreement between computational results and Langmuir waves has been observed by the Galileo spacecraft on 10 December 1990.