Observational connection between local high-temperature phenomena within magnetic clouds and the Sun

Magnetic clouds (MCs) frequently show abnormal high-ionization states of heavy ions. The abnormal high-charge distributions are related to the coronal temperature of their source regions. We examined the plasma and magnetic field data of 74 MCs observed by the Advanced Composition Explorer from February 1998 to December 2008. We determined that 14 of the 74 events showed local high-temperature phenomena. We analyzed the correlation between proton temperature and O-7/O-6 ratio (or high mean Fe charge state < Fe >) within the local high-temperature regions in the 14 MCs. Results show that proton temperature and O-7/O-6 ratio (or high mean Fe charge state) had good correlations in nine MCs, but had no evident correlation in the other five MCs. The local high-temperature phenomena within the nine MCs have resulted from the Sun.