A Challenging Solar Eruptive Event of 18 November 2003 and the Causes of the 20 November Geomagnetic Superstorm. II. CMEs, Shock Waves, and Drifting Radio Bursts

TL;DR

This study analyzes the complex solar eruptive event of November 2003, focusing on CMEs, shock waves, and radio bursts, to understand their potential impact on Earth's geomagnetic superstorm, revealing the event's dynamics and challenging previous source identifications.

Contribution

It provides a detailed multi-wavelength analysis of the 2003 solar event, clarifying the roles of CMEs and shock waves and questioning their direct connection to the superstorm.

Findings

Confirmed free propagation of shock waves during the event.

Reconciled shock kinematics with EUV waves and radio spectra.

Identified an additional eruption near the solar disk center.

Abstract

We continue our study (Grechnev et al. (2013), doi:10.1007/s11207-013-0316-6; Paper I) on the 18 November 2003 geoffective event. To understand possible impact on geospace of coronal transients observed on that day, we investigated their properties from solar near-surface manifestations in extreme ultraviolet, LASCO white-light images, and dynamic radio spectra. We reconcile near-surface activity with the expansion of coronal mass ejections (CMEs) and determine their orientation relative to the earthward direction. The kinematic measurements, dynamic radio spectra, and microwave and X-ray light curves all contribute to the overall picture of the complex event and confirm an additional eruption at 08:07 - 08:20 UT close to the solar disk center presumed in Paper I. Unusual characteristics of the ejection appear to match those expected for a source of the 20 November superstorm but make its detection in LASCO images hopeless. On the other hand, none of the CMEs observed by LASCO seem to be a promising candidate for a source of the superstorm being able to produce, at most, a glancing blow on the Earth's magnetosphere. Our analysis confirms free propagation of shock waves revealed in the event and reconciles their kinematics with "EUV waves" and dynamic radio spectra up to decameters.