CMEs(Coronal Mass Ejections) are an important means of energy release in the solar corona.Solar Polar Orbit Radio Telescope(SPORT) is a mission being proposed for observing the propagation of interplanetary CMEs from solar polar orbit.The main payload onboard SPORT is a synthetic aperture interferometric radiometer,which receives radio emission of interplanetary CMEs. It is identified that there are mainly three radio emission mechanisms of CMEs,i.e.,bremsstrahlung, gyrosynchrotron emission and plasma emission.Among these emission types,bremsstrahlung emission is the main emission mechanism of the high-density plasma clouds of interplanetary CMEs.Gyrosynchrotron emission is the continuous emission generated by high-energy electrons from CMEs, while plasma emission is the main mechanism of transient radio bursts from CMEs.In this paper,the gyrosynchrotron emission of interplanetary CMEs is focused on.Firstly,the mechanism of gyrosynchrotron emission is reviewed.Secondly,a review of the physical parameter models of background solar wind and interplanetary CMEs is presented.After these,the brightness temperature and polarization of gyrosynchrotron emission of interplanetary CMEs are calculated and analyzed.Finally, the detectability of gyrosynchrotron emission of interplanetary CMEs by radio meters is discussed briefly.
Synthetic aperture interferometric technique has wide applications in optics,radio astronomy and mi-crowave remote sensing areas.With the increasing demands of high resolution imaging observation,a new time-sharing sampling scheme of asynchronous rotation scan is proposed to meet the technical challenge of achieving a large equivalent aperture and overcome the operating barriers of space borne application.This configuration is basically composed by two asynchronously and concentrically ro-tating antenna groups,whose revolving radii and speeds are different.The synthetic aperture system with asynchronous rotation scanning scheme can effectively solve the trade-off problem of system complexity,and greatly simplify the system hardware at the cost of sacrificing a certain time resolution.The basic rules and design methods of asynchronous rotation scan are investigated The Gridding method is introduced to inverse the spiral sampling data for image reconstruction.The potential ap-plications of geostationary orbit(GEO)earth observation and solar polar orbit(SPO)plasma cloud observation are explored with numerical simulations to validate the significance and feasibility of this new imaging configuration.
