Long-term change in the ionosphere are expected due to increases in greenhouse gases in the lower atmosphere. Empirical formulae are used to estimate height. Through comparison with independent data we show that there are seasonal and long-term biases introduced by the empirical model. We conclude that estimates of long-term changes in ionospheric height need to account for these biases.

We aim to understand the link between the Sun's atmosphere, the corona, and the constant stream of plasma which escapes it, the solar wind. To do so we test how similar energetic electrons in the solar wind are to their earlier state in the corona, using oxygen ionisation states as a proxy. We find only a very weak link which varies with the type of solar wind stream and the 11-year solar cycle. We find minor evidence to suggest that this is due to solar wind processing during its outward flow.

We use THEMIS large data set of dipolarization front events to build a 2-D pressure distribution in XZ plane, and thus derive the current system around the dipolarization front. Our results show that a banana current loop is formed around the dipolarization front. This current is also suggested to be the reason for the magnetic dip observed ahead of the dipolarization front. In addition, the current density is too small to contribute a substorm current wedge.