Reply to comment by S. W. H. Cowley et al. on “Jupiter: A fundamentally different magnetospheric interaction with the solar wind”

Abstract

We welcome the comments by Cowley et al. [2008] (hereinafter referred to as CBIM), and discussion of McComas and Bagenal [2007]. In our paper we pointed out a variety of problems with the operation of an Earth‐like Dungey cycle at Jupiter including the large spatial and long temporal scales over which a solar‐wind‐driven convection system would need to operate, the presence of a high beta plasma sheet of iogenic material inhibits closing of open (lobe) flux in the magnetotail, the ejection of plasma sheet material down the tail inhibits planetward motion of closed (reconnected) flux tubes, and the lack of a signature of a polar cap in Jovian auroral emissions. We suggested an alternate process that would close open magnetic flux at the magnetopause any time a solar wind flux tube connects with open flux anchored in both poles. While we do not pretend to have fully proven that our process is the dominant method for closing off open magnetic flux in the Jovian magnetosphere, we do believe that it is an interesting and new idea that is worth serious consideration. In addition, there are already a variety of observations that support our general concept, as described in our paper. Ultimately, which process is the primary one will have to be settled by these and other observations – it will not be settled by conflicting models or theoretical arguments.