Willam B. Hanson Lecture (Observations)
The work of William B. Hanson (1923-1994) is a memorable example of the leadership and innovation that we now recognize as key to the robust advancement of understanding in Space Physics and Aeronomy. His contributions have been far reaching and have shaped many of the methods and techniques employed in modern-day research in the field of Space Science and Aeronomy. He was among the first to study the equatorial ionosphere and to reveal the influence of plasma and neutral motions on the spatial distribution of the plasma. He exposed the links between the thermal structure and dynamics in a plasma and was among the first to describe the observed variations in the ionospheres of Earth and Mars. He was also a pioneer in the innovative development of instrumentation that enabled the links between plasma density, temperature and velocity to be established observationally.