摘要
在太空等离子体中,尤其在等离子体内部磁场较弱时,轫致辐射是等离子体能量损失的主要机制.本文对太阳宁静及耀斑期间1 AU处等离子体轫致辐射计算表明,等离子体辐射强度If的变化与辐射的电磁波频率有直接的关系.当辐射频率f接近于等离子体频率fpe时,辐射强度显著增大.随着电磁波辐射频率的增大,辐射强度随频率增大作缓慢对数下降.辐射亮温Tb与等离子体电子温度Te介质光深成正比. Tb与If随辐射频率变化的整体趋势一致.在相同的辐射频率情况下,太阳宁静期间If值、Tb值低于太阳耀斑期间If值、Tb值.
Bremsstrahlung is the main mechanism of energy loss of space plasma when the magnetic field in plasma is weak. The results calculated at 1 AU of Bremsstrahlung radiation show that the variation of emission intensity If has direct relation to the frequency of electromagnetic wave which has been radiated from the plasma. The emission intensity will increase sharply when the emission frequency is close to plasma frequency. The emission intensity will logarithmically decrease slowly when the emission frequency increase. The brightness temperature Tb is proportional to the electron temperature Tb and optical depth of the medium. The variation tendency of Tb is consistent with that of If. The emission intensity and brightness temperature in quiet sun period are lower than that of in solar flare at the same emission frequency.
出处
《空间科学学报》
CAS
CSCD
北大核心
2004年第6期412-420,共9页
Chinese Journal of Space Science
基金
国家863项目13主题资助(2001AA132030)
