Open Access

Halo coronal mass ejections and geomagnetic storms

Earth, Planets and Space200961:BF03352930

Received: 21 June 2008

Accepted: 27 October 2008

Published: 29 May 2009


In this letter, I show that the discrepancies in the geoeffectiveness of halo coronal mass ejections (CMEs) reported in the literature arise due to the varied definitions of halo CMEs used by different authors. In particular, I show that the low geoeffectiveness rate is a direct consequence of including partial halo CMEs. The geoeffectiveness of partial halo CMEs is lower because they are of low speed and likely to make a glancing impact on Earth.


Coronal mass ejectionsgeomagnetic stormsgeoeffectivenesshalo CMEs