| Abstract |
Central stars in planetary systems and star forming regions are not only the major gravitational source but also an important source of large disturbances in these systems. The sun, a typical star, produces solar flares by releasing magnetic energy stored above sunspots. Mass ejections associated with flares disturbs the magnetosphere of planets and erode their atmospheres. When we look at much younger stars like protostars and pre-main-sequence stars, we will find that they drive more violent explosions than the sun. Flares produces strong X-ray emissions and high energy particles, which has impact on the chemical evolution and accretion structure of the disk by changing the chemical reaction and ionization degree. Moreover, accreting stars can produce high energy particles via accretion shocks and jets. We have been working on MHD modeling of solar and protostellar flares and accretion onto young stars which is necessary for evaluation of these impacts. In this talk, we will begin with an overview of magnetic energy storage and release of solar flares. Our studies will me also mentioned in the introduction. Then, I will investigate the accretion and magnetic structures around an accreting protostar on the basis of our MHD simulations, and discuss the potential impact on protoplanetary disks. |
