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Y. Yi (Chungnam National University), T. Ogino (Nagoya University), R.J. Walker (UCLA), J.C. Brandt (University of New Mexico), S.J. Kim (Kyunghee University)
We have used a three-dimensional global magnetohydrodynamic simulation code to model the effects of an interplanetary shock on cometary plasma tails. In our simulation an interplanetary shock interacts with an H2O+ rich comet. After the shock hits the comet, two regions of enhanced density called condensations form in the plasma tail. These condensations create the appearance that the plasma tail is disconnected from the comet. However, careful analysis indicates that this is not true. The first density enhancement is a compression of the tail caused by the shock front while the second density enhancement is made of plasma that is stripped from the comet and then redistributed after the comet adjusts to the higher solar wind dynamic pressure. There is no evidence that the interplanetary shock caused reconnection in the tail. The response of the comet to the interplanetary shock is very different from that caused by a heliospheric current sheet crossing. In our simulations of current sheet crossings reconnection causes the old tail to be disconnected. The location of the disconnection in the current sheet simulations is much closer to the comet than the density enhancements in the shock simulations.
The author(s) of this abstract have provided an email address for comments about the abstract: euyiyu@cnu.ac.kr