2012MNRAS.427..180L

The research presented here examines an 8-h observation of pulsar B1822-09, taken by the Giant Metrewave Radio Telescope. B1822-09 has been known to exhibit two stable emission modes, the B-mode, where the precursor (PC) `turns-on', and the Q-mode, which is defined by interpulse (IP) emission. The results of our analysis, of this extremely long observation, have shown that B1822-09 exhibits at least three other emission behaviours that have not been seen before in other similar pulsars or in other observations of B1822-09. These three behaviours can be described as Q-mode emission with PC emission, B-mode emission with IP emission and instances where both the PC and IP are `on' when transitioning from one mode to the other. The pulse structure has been found to be more complex than previously thought. The main pulse (MP) has an inner cone/core triple (T) configuration together with a central sightline traverse. The IP is a 15°-wide region that along with the MP originate from an open dipolar field. The PC emission comes from a still unknown source. We argue that the PC emission arises within the same region as the MP, but likely comes from higher in the magnetosphere. The Q-mode has a very clear fluctuation that occurs in both the MP and IP at 46.6-P₁ which is associated with drifting subpulses. Furthermore, we have found that the B-mode, which has previously never shown any detectable modulations at this radio frequency, has a very weak feature at 70-P₁. Coincidently we find the ratio of the B-mode `P<sub>3</sub>' of 70-P<sub>1</sub> to its Q-mode counterpart of 46.6-P<sub>1</sub> is very nearly 3/2, which seems to imply a carousel of three MP `sparks' in the Q-mode and two sparks in the B-mode. The circulation times of the two modes have been found to be virtually equal at 140-P₁, which allows for this interpretation of the fluctuation features as `sparks'. Overall, our analyses strongly suggest that mode changes allow information transfer between the two magnetic polar regions and contribute to global magnetospheric changes.