Sun-Induced Space Weather: Understanding and Forecasting

Manolis K. Georgoulis

Space Exploration Sector, Johns Hopkins APL


Abstract

The Sun is a partially convective, magnetically active star with cycles of
activity that have an average duration of about 11 years for complete magnetic
polarity reversal. At shorter timescales, solar cycles have ascending phases,
maxima and descending phases characterized mainly by varying numbers of
sunspot complexes in the photosphere, the base of the solar atmosphere.

Sunspots statistically imply explosive (solar flares) and eruptive (coronal
mass ejections) magnetic activity that drives the bulk of the variable space
weather conditions in the heliosphere, namely the sphere of Sun's magnetic
influence. The complete span of space-weather processes shows a staggering
dynamical range of at least 8 orders of magnitude in space and time, from
sub-kilometer scales to astronomical units, and from seconds to years.  We
briefly recount the basic physical and statistical features for understanding
space weather and then proceed to some basic space weather forecasting
methodologies and ways of evaluating their performance. 

We highlight the fascinating interdisciplinary aspects behind these efforts
and attempt to outline the current state-of-the-art. It will become clear
that the current status shows more challenges than achievements and calls
for continuing and renewing investment in expertise and ingenuity, for
humanity to continue making strides in space exploration.

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Manolis K. Georgoulis
Space Exploration Sector / SRP Group
Johns Hopkins APL
11100 Johns Hopkins Road
Laurel, MD 20723, USA
manolis.georgoulis@jhuapl.edu