New insight into the circular polarisation of radio

We present a study of single pulses from nine bright northern pulsars to investigate the behaviour of circular polarisation, V . The observations were conducted with the Effelsberg 100-m radio telescope at 1.41 GHz and 4.85 GHz and the Westerbork radio telescope at 352 MHz. For the first time, we present the average profile of the absolute circular polarisation |V | in the single pulses. We demonstrate that the average profile of |V | is the distinguishing feature between pulse components that exhibit low V in the single pulses and components that exhibit high V of either handedness, despite both cases resulting in a low mean. We also show that the |V | average profile remains virtually constant with frequency, which is not generally the case for V , leading us to the conclusion that |V | is a key quantity in the pulsar emission problem.