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Ion Charge States in a Time-Dependent Wave-Turbulence-Driven Model of the Solar Wind

Raymond, John; Velli, Marco; Downs, Cooper +4 more

Ion fractional charge states, measured in situ in the heliosphere, depend on the properties of the plasma in the inner corona. As the ions travel outward in the solar wind and the electron density drops, the charge states remain essentially unaltered or "frozen in". Thus they can provide a powerful constraint on heating models of the corona and ac…

On the Power-Law Distribution of Pitch-Angle Scattering Times in Solar Wind Turbulence

Zimbardo, Gaetano; Perri, Silvia; Pucci, Francesco +1 more

The propagation of energetic particles in the solar wind depends in a sensitive way on the pitch-angle scattering of particles in the presence of magnetic turbulence. The well-known quasi-linear theory gives an expression for the pitch-angle scattering rate under the assumption of small turbulence levels, but both in the solar wind and in other as…

New Evidence for Third Harmonic Electromagnetic Radiation in Interplanetary Type III Solar Radio Bursts

MacDowall, R. J.; Reiner, M. J.

This article provides new evidence for a third harmonic component in the electromagnetic radiation generated by interplanetary type III solar radio bursts observed locally near 1 AU. This evidence comes mainly from the analysis of the low-frequency radio emissions observed by the Wind spacecraft. The analysis examines, at high-time and high-freque…

Comparative Study of Microwave Polar Brightening, Coronal Holes, and Solar Wind over the Solar Poles

Masuda, Satoshi; Yashiro, Seiji; Shibasaki, Kiyoto +3 more

We compared the long-term variation (1992 - 2017) in solar polar brightening observed with the Nobeyama Radioheliograph, the polar solar-wind velocity with interplanetary scintillation observations at the Institute for Space-Earth Environmental Research, and the coronal-hole distribution computed by potential-field calculations of the solar corona…