报告题目：The induced global looping magnetic fields on Venus and Mars
报告人：柴立晖 中国科学院地质与地球物理研究所 副研究员
报告摘要：Venus and Mars have no significant intrinsic magnetic dipoles, they serve as the prototype of solar wind interaction with unmagnetized planetary bodies with atmospheres. The global magnetic field around them are believed to be formed by the draped interplanetary magnetic field (IMF). However, some of the observed large-scale magnetic fields are inconsistent with the draped field pattern. Here we show that besides the draped fields, there is a second type of induced global magnetic fields on both Venus and Mars. These global looping fields have distributions in cylindrical shell around the magnetotail and counterclockwise directions looking from the planetary tails toward the Sun. The looping field is a common feature of unmagnetized planets with atmospheres. The observed solar wind flows along the azimuth direction towards the –E (conventional electrical field) hemisphere by MAVEN agrees with the looping field morphology and provides a possible cause for the looping field. The current system associated with the looping field and its possible connection with the nightside ionosphere formations and ion escapes on Mars and Venus are discussed.