摘要: A new theory of the mirror instability is developed which includes effects ∇B and ∇n, finite Larmor radius, a coexisting cold plasma. It shown that becomes overstable with frequency equal to drift wave frequency, may be determined by wave‐number gives maximum growth rate. The applied explain sudden kink in increase (decrease) proton flux (magnetic field) subsequent oscillations observed during storm time on 18 April 1965 detectors Explorer 26 satellite.