Peculiar Current Solar-Minimum - Structure of the Heliosphere

TL;DR

This paper reviews the 3-D evolution of the inner heliosphere during solar cycle 23's minimum, highlighting significant differences in solar wind turbulence and structure compared to previous cycles, based on IPS observations.

Contribution

It provides new insights into the solar wind density turbulence and heliospheric structure during a peculiar solar minimum using 3-D modeling and IPS data.

Findings

Solar wind density turbulence was about 50% lower than in the previous minimum.

The corona's scattering diameter decreased steadily after 2003.

Solar wind speed data align with polar magnetic field strength and heliospheric current sheet warping.

Abstract

In this paper, I review the results of 3-D evolution of the inner heliosphere over the solar cycle #23, based on observations of interplanetary scintillation (IPS) made at 327 MHz using the Ooty Radio Telescope. The large-scale features of solar wind speed and density turbulence of the current minimum are remarkably different from that of the previous cycle. The results on the solar wind density turbulence show that (1) the current solar minimum is experiencing a low level of coronal density turbulence, to a present value of ~50% lower than the previous similar phase, and (2) the scattering diameter of the corona has decreased steadily after the year 2003. The results on solar wind speed are consistent with the magnetic-field strength at the poles and the warping of heliospheric current sheet.