Considering the effects of ion nonlinear polarization drift and warm ions, we adopt two-fluid model to investigate the character of low-frequency Solitary Kinetic Alfven Wave (SKAW hereafter) in a magnetic plasma. The...Considering the effects of ion nonlinear polarization drift and warm ions, we adopt two-fluid model to investigate the character of low-frequency Solitary Kinetic Alfven Wave (SKAW hereafter) in a magnetic plasma. The results derived in this paper indicate that dip SKAW and hump SKAW both exist in a wide range in magnetosphere (for the pressure parameter β-10^-5 -0.01, where β is the ratio of thermal pressure to magnetic pressure, i.e.β=2μonT/B0^2 ). These two kinds of SKAWs propagate at either Super-Alfvenic velocity or Sub-Alfvenic velocity. In the inertial region β<<me/mi, the Sub-Alfvenic velocity dip SKAWs and hump SKAWs both exist; in the transmittal region β-2me/mi, dip SKAWs and hump SKAWs propagate at Super-Alfvenic velocity or Sub-Alfvenic velocity;Super-Alfvenic velocity hump SKAWs and Super-Alfvenic and Sub-Alfvenic velocity dip SKAWs are in the kinetic region 1>>β>>me/mi. These results are different from previous ones. That indicates that the effects of ion nonlinear polarization drift and warm ions are important and they cannot be neglected. The SKAW has an electric field parallel to the ambient magnetic field, which makes the SKAW take an important role in the acceleration and energization of field-aligned charged particles in magnetic plasmas. And the SKAW is also important for the heating of a local plasma.So it makes a novel physical mechanism of energy transmission possible.展开更多
文摘Considering the effects of ion nonlinear polarization drift and warm ions, we adopt two-fluid model to investigate the character of low-frequency Solitary Kinetic Alfven Wave (SKAW hereafter) in a magnetic plasma. The results derived in this paper indicate that dip SKAW and hump SKAW both exist in a wide range in magnetosphere (for the pressure parameter β-10^-5 -0.01, where β is the ratio of thermal pressure to magnetic pressure, i.e.β=2μonT/B0^2 ). These two kinds of SKAWs propagate at either Super-Alfvenic velocity or Sub-Alfvenic velocity. In the inertial region β<<me/mi, the Sub-Alfvenic velocity dip SKAWs and hump SKAWs both exist; in the transmittal region β-2me/mi, dip SKAWs and hump SKAWs propagate at Super-Alfvenic velocity or Sub-Alfvenic velocity;Super-Alfvenic velocity hump SKAWs and Super-Alfvenic and Sub-Alfvenic velocity dip SKAWs are in the kinetic region 1>>β>>me/mi. These results are different from previous ones. That indicates that the effects of ion nonlinear polarization drift and warm ions are important and they cannot be neglected. The SKAW has an electric field parallel to the ambient magnetic field, which makes the SKAW take an important role in the acceleration and energization of field-aligned charged particles in magnetic plasmas. And the SKAW is also important for the heating of a local plasma.So it makes a novel physical mechanism of energy transmission possible.