Examining Ion Temperature Anisotropy using AMISR Data

One of the longstanding problems in ionospheric science is that we assume the F-region ion temperature to be isotropic, meaning the ion temperature is the same in all directions with respect to the magnetic field. However, works from St.-Maurice et al., (1976), and Raman et al., (1981), show that in times of heating due to moderate to strong electric fields (above 50 mV/m), the O+ velocity distribution distorts, and the ion temperature becomes anisotropic. Here, data from advanced modular incoherent scatter radars, or AMISRs, like the resolute bay incoherent scatter radars RISR-N and RISR-C, and the poker flat incoherent scatter radar, PFISR, taken during strong heating events (generally events consistently above 1500 K for at least 1 hour) are used to resolve a temperature perpendicular to the magnetic field and a temperature parallel to the magnetic field. AMISRs make this possible by using multiple beams that scan the same magnetic flux tube at different aspect angles with minimal time delay. This presentation will give preliminary results of this technique.