Alfvén波与等离子体的共振相互作用
|
摘要
采用粒子模拟(PIC)方法,研究沿背景磁场传播的Alfvén波与均匀磁化等离子体共振相互作用的过程.模拟结果表明:共振加热过程中,在平行和垂直于背景磁场的方向上,质子温度均得到增加,且垂直方向上的温度增加更为明显,等离子体温度呈现各向异性;同时,不同的波频率影响波粒子加热效果,并且一定范围内,共振加热期间,共振波频率越大,加热效果越好.而经过随机加热后,粒子动力学温度的最大值与波频率无关,仅仅与波的相速度相关.
Using the test particle simulation method,the interactions between the uniform magnetized plasmas and Alfvén waves propagating along background magnetic field are studied. The results show that,in the heating process,the proton temperature in parallel and perpendicular directions of the background magnetic field are elevated. The increase of temperature in vertical direction is more obvious than that in the parallel direction,and the temperature of plasmas exhibits anisotropy. Meanwhile,the frequencies of waves have an effect on the heating. The effect of resonance heating is better than that of non-resonance heating. Moreover,in resonance heating period within a certain range,the frequency is larger,the heating effect is better. After stochastic heating,the maximum kinetic temperatureof ions is only dependent on phase velocity of the Alfvén waves and has no relevance with the frequency of Alfvén waves.
Using the test particle simulation method,the interactions between the uniform magnetized plasmas and Alfvén waves propagating along background magnetic field are studied. The results show that,in the heating process,the proton temperature in parallel and perpendicular directions of the background magnetic field are elevated. The increase of temperature in vertical direction is more obvious than that in the parallel direction,and the temperature of plasmas exhibits anisotropy. Meanwhile,the frequencies of waves have an effect on the heating. The effect of resonance heating is better than that of non-resonance heating. Moreover,in resonance heating period within a certain range,the frequency is larger,the heating effect is better. After stochastic heating,the maximum kinetic temperatureof ions is only dependent on phase velocity of the Alfvén waves and has no relevance with the frequency of Alfvén waves.
引文
[1]Miller J A.Magnetohydroynamic turbulence dissipation and stochastic proton acceleration in solar flares[J].Astrophys.J.,1991,376(1):342-354.
[2]Wu C S,Yoon P H,Chao J K.Motion of ions influenced by enhanced Alfven waves[J].Phys.Plasmas,1997,4(3)856-862.
[3]Abe H,Okada H,Itatani R,et al.Resonant heating due to cyclotron subharmonic frequency waves[J].Phys.Rev.Lett.,1984,53(12):1153-1156.
[4]王斌.Alfvén波对离子的非共振加热与加速[D].合肥:中国科学技术大学,2012.
[5]Chen L,Lin Z,White R.On resonant heating below the cyclotron frequency[J].Phys.Plasma.,2001,8(11):4713-4716.
[6]Lu Q M,Chen L.Ion heating by a spectrum of obliquely propagating low-frequency Alfvén waves[J].Astrophys.J.,2009,704(1):743.
[7]White R B,Chen L,Lin Z H.Resonant plasma heating below the cyclotron frequency[J].Phys.Plasmas,2002,9(5):1890-1897.
[8]Li K H,Gong X Y,Lu X Q,et al.Phase-matching enhanced ion heating by nonresonant Alfvén waves[J].Phys.Plasmas,2012,19(7):072118-1-5.
[9]李克华,龚学余,路兴强,等.低频Alfvén波对等离子体非共振加热与随机加热的粒子模拟[J].计算物理,2012,29(5):739-744.
[10]Lu Q M,Li X.Heating of ions by low frequency Alfvén waves[J].Phys.Plasmas,2007,14(4):042303-6.
[11]Cranmer S R,Kohl J L,Noci G,et al.An empirical model of a polar coronal hole at solar minimum[J].The Astrophysical Journal,1999,511(1):481-501.
[2]Wu C S,Yoon P H,Chao J K.Motion of ions influenced by enhanced Alfven waves[J].Phys.Plasmas,1997,4(3)856-862.
[3]Abe H,Okada H,Itatani R,et al.Resonant heating due to cyclotron subharmonic frequency waves[J].Phys.Rev.Lett.,1984,53(12):1153-1156.
[4]王斌.Alfvén波对离子的非共振加热与加速[D].合肥:中国科学技术大学,2012.
[5]Chen L,Lin Z,White R.On resonant heating below the cyclotron frequency[J].Phys.Plasma.,2001,8(11):4713-4716.
[6]Lu Q M,Chen L.Ion heating by a spectrum of obliquely propagating low-frequency Alfvén waves[J].Astrophys.J.,2009,704(1):743.
[7]White R B,Chen L,Lin Z H.Resonant plasma heating below the cyclotron frequency[J].Phys.Plasmas,2002,9(5):1890-1897.
[8]Li K H,Gong X Y,Lu X Q,et al.Phase-matching enhanced ion heating by nonresonant Alfvén waves[J].Phys.Plasmas,2012,19(7):072118-1-5.
[9]李克华,龚学余,路兴强,等.低频Alfvén波对等离子体非共振加热与随机加热的粒子模拟[J].计算物理,2012,29(5):739-744.
[10]Lu Q M,Li X.Heating of ions by low frequency Alfvén waves[J].Phys.Plasmas,2007,14(4):042303-6.
[11]Cranmer S R,Kohl J L,Noci G,et al.An empirical model of a polar coronal hole at solar minimum[J].The Astrophysical Journal,1999,511(1):481-501.