Dynamical response of the magnetotail to changes of the solar wind direction: an MHD modeling perspective

Результат исследований: Научные публикации в периодических изданияхстатья

18 Цитирования (Scopus)
2 Загрузки (Pure)

Аннотация

We performed global MHD simulations to investigate
the magnetotail response to the solar wind directional
changes (Vz-variations). These changes, although small,
cause significant variations of the neutral sheet shape and location
even in the near and middle tail regions. They display
a complicated temporal response, in which 60 to 80% of the final shift of the neutral sheet in Z direction occurs within first 10–15 min (less for faster solar wind), whereas a much longer time (exceeding half hour) is required to reach
a new equilibrium. The asymptotic equilibrium shape of the simulated neutral sheet is consistent with predictions of Tsyganenko-Fairfield (2004) empirical model. To visualize a physical origin of the north-south tail motion we compared
the values of the total pressure in the northern and southern tail lobes and found a considerable difference (10–15% for only 6 change of the solar wind direction used in the simulation). That difference builds up during the passage of the solar wind directional discontinuity and is responsible for the vertical shift of the neutral sheet, although some pressure difference remains in the near tail even near the new equilibrium. Surprisingly, at a given tailward distance, the response
was found to be first initiated in the tail center (the “leader effect”), rather than near the flanks, which can be explained by the wave propagation in the tail, and which may have interesting implications for the substorm triggering studies. The
present results have serious implications for the data-based
modeling, as they place constraints on the accuracy of tail
magnetic configurations to be derived for specific events using
data of multi-spacecraft missions, e.g. such as THEMIS.
Язык оригиналаАнглийский
Страницы (с-по)2395-2402
Число страниц8
ЖурналAnnales Geophysicae
Том26
Номер выпуска8
DOI
СостояниеОпубликовано - 2008
Опубликовано для внешнего пользованияДа

Предметные области Scopus

  • Физика и астрономия (все)

Ключевые слова

  • magnetosphere
  • magnetotail
  • solar wind

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