In addition to his substantial legacy of published work, Henry Rishbeth summarised what he regarded as the open questions in Earth Ionospheric Physics that should attract the attention of the science community over years and decades to come.

Many of the following questions were posed by Henry in an EOS article (H. Rishbeth: “Thermospheric Targets”, EOS, 88, 24 April 2007 - Download PDF) and more recently in discussions with colleagues.

We particularly welcome contributions to this meeting which address any of the questions outlined below, or relate to them.

Theme 1: Seasonal and long-term trends in the atmosphere

1.1 Semiannual variations of temperature & hmF2 - what is their origin?

1.2 Annual asymmetry in the F2 layer - what causes it?

1.3 Why are seasonal changes near equinox so rapid?

1.4 Long-term changes in the ionosphere - what are their characteristics and origins?

Theme 2: Vertical coupling

2.1 How effectively does eddy mixing of neutral gases affect the ionosphere?

2.2 Are systematic differences present in 'continental' and 'oceanic' ionospheres?

2.3 To what extent is ionospheric structure driven by vertical neutral winds?

Theme 3: Ionospheric storms

3.1 How does ionospheric response to geomagnetic activity systematically vary with universal time & local time & season?

3.2 Does the ionosphere have a memory, does geomagnetic "preconditioning" exist?

Theme 4: Short-term and small-scale variations in the ionosphere

4.1 What generates day-to-day variability of F2 layer?

4.2 Why does F-layer survive during night time, especially in winter?

4.3 Does the ionosphere have preferred time scales (40 min, 26 h)? Why?

4.4 Is apparent 500 km correlation distance for F2 and other layers real,and what controls it?