Effects of a Tilted Heliospheric Current Sheet in the Heliosheath: 3D MHD Modeling
Abstract
Recent observations indicate that Voyager 1, now beyond 90 AU, is in a region unlike any encountered in it's 26 years of exploration. There is currently a controversy as to whether Voyager 1 has already crossed the Termination Shock, the first boundary of the Heliosphere (Krimigis et al. 2003; McDonald et al. 2003, Burlaga et al. 2003). An important aspect of this controversy is our poor understanding of this region. The region between the Termination Shock and the Heliopause, the Helisheath, is one of the most unknown regions theoretically. In the Heliosheath magnetic effects are crucial, as the solar magnetic field is compressed at the Termination Shock by the slowing flow. Therefore, to accurately model the Heliosheath the inclusion of the solar magnetic field is crucial. Recently, our simulations showed that the Heliosheath presents remarkable dynamics, with turbulent flows and a presence of a jet flow at the current sheet that is unstable due to magnetohydrodynamic instabilities (Opher et al. 2003; 2004). We showed that to capture these phenomena, spatial numerical resolution is a crucial ingredient, therefore requiring the use of an adaptive mesh refinement (AMR). These previous works assumed that the solar rotation and the magnetic axis were aligned. Here we present for the first time results including the tilt of the heliocurrent sheet using a 3D MHD AMR simulation, with BATS-R-US code. We discuss the effects on the global structure of the Heliosheath, the flows, turbulence and magnetic field structure. We assess the consequences for the observations measured by Voyager 1 since mid-2002.
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2004
- Bibcode:
- 2004AGUFMSH42A..02O
- Keywords:
-
- 7524 Magnetic fields;
- 7811 Discontinuities;
- 7839 Nonlinear phenomena;
- 7843 Numerical simulation studies;
- 7863 Turbulence