On the O-mode instability generated by dual core-halo solar wind electrons

Abstract

Abstract In situ measurements reported with different spacecraft reveal the temperature anisotropy constraints of solar wind species. Micro-instabilities driven by the temperature anisotropy are investigated as key mechanism which limit an unchecked rise in the temperature anisotropy in dilute space plasmas. The present study considers the excitation of O-mode instability under the excessive electrons parallel temperature condition i.e., T ‖e > T ⊥e . Looking at the recent developments made by different satellite missions, a dual core-halo electron distribution is employed that represents a true picture of solar wind electrons. We employ Vlasov–Maxwell’s model equations and derive the dispersion relation of the O-wave whose analytical solution characterizes the growth rate of O-mode instability. We take different sets of temperature anisotropy and beta combinations associated with core-halo electron components that highlight the instability characteristics e.g. growth rate and the range of wave number of unstable mode. We note an increment in the growth rate with the increase of anisotropic ratios associated either with core electrons or halo electrons and or the combination thereof. In view of a global perspective of solar wind, it may be a favorable study with the contribution of non-thermal solar wind electrons.