Relativistic nucleon and electron production in the 2003 October 28 solar eventстатья
Статья опубликована в высокорейтинговом журнале
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Дата последнего поиска статьи во внешних источниках: 4 октября 2013 г.
Аннотация:A flare on 2003 October 28 produced a relativistic particle event at Earth, although the
active region AR 10486 was located to the east of the central meridian of the Sun. The
paper considers features related to the acceleration at the Sun and the propagation to
the Earth of energetic particles in this event, which occurred on a disturbed interplanetary
background caused by preceding activity on the Sun and a corotating high-speed solar
wind stream. From a study of the onset times of the event at different neutron monitors, we
conclude that the earliest arriving solar particles were neutrons. The first relativistic
protons arrived a few minutes later. Among relativistic solar protons (RSP), two
populations could clearly be distinguished: prompt and delayed ones. The prompt solar
protons caused an impulse-like increase at a few neutron monitor stations. The delayed
solar protons arrived at Earth 0.5 hours later. Both prompt and delayed relativistic protons
arrived at Earth from the antisunward direction. On the other hand, subrelativistic
electrons that were traced by their radio emission from meter waves (Nanc¸ay
Radioheliograph and Decametric Array) to kilometer waves (Wind/WAVES) are
accompanied by metric radio emission in the western solar hemisphere, far from the
flaring active region. We propose a scenario that reconciles the unusual features of
energetic particles at the Earth with the observed structure of the interplanetary magnetic
field, which suggests the Earth is at the interface between an interplanetary
coronal mass ejection (ICME) and a corotating stream during the event. In this scenario
the high-energy protons and electrons are accelerated in the flaring active region, injected
into the eastern leg of an ICME loop rooted in the active region, and reach the Earth
from the antisunward direction after passing through the summit of the loop. We attribute
the promptly escaping subrelativistic electrons to acceleration in the western solar
hemisphere and propagation along the nominal Parker spiral.