Measurement of energy absorption flux during ionospheric heating in polar region

Based on energy and momentum equations, the energy absorption flux near the reflection height is calculated by using the electron density, electron temperature and ion temperature measured in the heating campaign on August 16-19 2009. It is shown that the energy absorption flux is close to Gauss distribution, but the structure is not symmetric along beam absorption centre. The curve of absorption maximum with frequency difference exists break point near 0.6MHz, and we can carry out an optimization heating in a critical state, which is important for building the experiential and semi-experiential model of energy absorption flux.