The Prelude to the Deep Minimum between Solar Cycles 23 and 24: Interplanetary Scintillation Signatures in the Inner Heliosphere

TL;DR

This study analyzes interplanetary scintillation data from 1983 to 2009, revealing a significant decline in heliospheric turbulence starting around 1995, indicating the onset of the deepest solar minimum in a century.

Contribution

It links IPS observations with solar polar field decline, providing new insights into the early signs of the upcoming deep solar minimum.

Findings

Significant drop in turbulence levels since ~1995

Correlation between IPS signatures and solar polar field decline

Indication of the deep solar minimum beginning over a decade earlier

Abstract

Extensive interplanetary scintillation (IPS) observations at 327 MHz obtained between 1983 and 2009 clearly show a steady and significant drop in the turbulence levels in the entire inner heliosphere starting from around ~1995. We believe that this large-scale IPS signature, in the inner heliosphere, coupled with the fact that solar polar fields have also been declining since ~1995, provide a consistent result showing that the buildup to the deepest minimum in 100 years actually began more than a decade earlier.