From Sun to Interplanetary Space: What is the Pathlength of Solar Energetic Particles?

Viewing radiation signatures of solar energetic particles in interplanetary space

A current serious limitation on the studies of solar energetic particle (SEP) events is that their properties in the inner heliosphere are studied only through in situ spacecraft observations. Our understanding of spatial distributions and temporal variations of SEP events has come through statistical studies of many such events over several solar cycles. In contrast, flare SEPs in the solar co...

Interplanetary Plasma Scattering Diagnostics from Anisotropy-time Profiles of Solar Energetic Particles

The anisotropy-time profile of solar particle events provides a powerful diagnostics tool to the interplanetary plasma scattering parameters of energetic charged particles. In the weak focusing limit of the transport of solar particles in axisymmetric MHD turbulence, the particle anisotropy consists of two contributions, the streaming and the ComptonGetting contribution, resulting from the para...

Solar cycle 24: what is the Sun up to

of an M7.9 class flare on 13 March 2012. It is shown here in the 131 Å wavelength, which is particularly good for seeing solar flares and is typically colourized in teal. The flare was from the same active region, no. 1429, that produced flares and coronal mass ejections the entire week. The region had been moving across the face of the Sun since 2 March, then rotated out of Earth view. But per...

UNDERSTANDING NEW ELEMENTS OF ACCELERATION AND TRANSPORT OF SOLAR ENERGETIC PARTICLES (SEPs) FROM THE SUN TO THE EARTH

Propagation of Solar Energetic Particles in Three-dimensional Interplanetary Magnetic Fields

This paper presents a model calculation of solar energetic particle propagation in a three-dimensional interplanetary magnetic field. The model includes essentially all the particle transport mechanisms: streaming along magnetic field lines, convection with the solar wind, pitch-angle diffusion, focusing by the inhomogeneous interplanetary magnetic field, perpendicular diffusion, and pitch-angl...