The heliospheric magnetic flux budget

There has recently been much debate about whether the long interplanetary coronal mass ejection (ICME) flux opening times (months to years) inferred by counter-streaming electron (CSE) observations lead to a catasphrophic build of magnetic flux in the heliosphere. As no such ``flux catastrophe'' is observed, this has questioned the validity of CSEs as a signature of closed flux. In this study we simulate heliospheric flux as a constant background open flux with a time-varying ICME contribution. Coronagraph observations are used to determine CME rates, while in situ observations are used to estimate the magnetic flux content of a typical ICME. The flux carried by ejecta can only to contribute to the heliospheric flux budget while the flux remains closed, and it is assumed that closed flux decays exponentially with time. Both static equilibrium and dynamic simulations require ICME fluxing opening times ~ 200 days in order to match the observed doubling in the magnetic field intensity at 1 AU over the solar cycle; no flux catastrophe results.