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电磁波被尘埃等离子体散射的功率谱 被引量:4
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作者 李芳 o.havnes 《电子科学学刊》 CSCD 1999年第5期679-685,共7页
用等离子体动力论导出的动力形状因子研究尘埃等离子体的散射功率谱。结果表明由于尘埃粒子具有大的荷电量,对于冷电子的非相干散射,即kλ_D1(λ_D是德拜屏蔽长度,K=|k|=|Ks-Ko|,Ko是入射波矢,ks是散射波矢),尘埃粒子极大地影响散射谱... 用等离子体动力论导出的动力形状因子研究尘埃等离子体的散射功率谱。结果表明由于尘埃粒子具有大的荷电量,对于冷电子的非相干散射,即kλ_D1(λ_D是德拜屏蔽长度,K=|k|=|Ks-Ko|,Ko是入射波矢,ks是散射波矢),尘埃粒子极大地影响散射谱的特征。散射功率谱在尘埃粒子声波频移处出现特征峰。 展开更多
关键词 尘埃等离子体 非相干散射 散射功率谱 电磁波
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尘埃等离子体中的低频电荷密度涨落 被引量:1
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作者 李芳 吕保维 o.havnes 《中国科学(A辑)》 CSCD 1996年第10期954-960,共7页
从等离子体动力论出发,推导尘埃等离子体介电张量表达式,用它研究尘埃等离子体的低频电荷密度涨落.结果表明描述尘埃粒子“浓度”的参量P,及反映尘埃粒子电荷可变性的参量:尘埃粒子充电频率Ω_c,决定了尘埃等离子体中的低频电荷密度涨... 从等离子体动力论出发,推导尘埃等离子体介电张量表达式,用它研究尘埃等离子体的低频电荷密度涨落.结果表明描述尘埃粒子“浓度”的参量P,及反映尘埃粒子电荷可变性的参量:尘埃粒子充电频率Ω_c,决定了尘埃等离子体中的低频电荷密度涨落的特征.对于P<<l的尘埃等离子体,当尘埃粒子充电频率Ω_c远小于尘埃粒子等离子体特征频率(?)时,尘埃等离子体中存在较强的低频电行密度涨落,其频谱具有尘埃粒子声波本征模的特征;而对于P>>l的尘埃等离子体,当Ω_(?)远大于(?)时,电荷密度涨落强度小,且涨落具有宽的频谱.将此结果用于讨论地球电离层,计算结果表明当电离层中存在的尘埃粒子的密度和尘埃粒子的半径在一定的范围内时,电离层中存在强度大的并具有尘埃粒子声波本征模频谱特征的甚低频电荷密度涨落. 展开更多
关键词 尘埃等离子体 电荷密度涨落 尘埃粒子 充电频率
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Charge density fluctuation of low frequency in a dusty plasma 被引量:2
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作者 李芳 吕保维 o.havnes 《Science China Mathematics》 SCIE 1997年第2期206-213,共8页
The charge density fluctuation of low frequency in a dusty plasma, which is derived from the longitudinal dielectric permittivity of the dusty plasma, has been studied by kinetic theory. The results show that the P va... The charge density fluctuation of low frequency in a dusty plasma, which is derived from the longitudinal dielectric permittivity of the dusty plasma, has been studied by kinetic theory. The results show that the P value, which describes the relative charge density on the dust in the plasma, and the charging frequency of a dust particle Ωc, which describes the ratio of charge changing of the dust particles, determine the character of the charge density fluctuation of low frequency. For a dusty plasma of P<<1, when the charging frequency Ωc is much smaller than the dusty plasma frequency wd, there is a strong charge density fluctuation which is of character of dust acoustic eigen wave. For a dusty plasma of P>>1, when the frequency Ωc, is much larger than wd there are weaker fluctuations with a wide spectrum. The results have been applied to the ionosphere and the range of radius and density of dust particles is found, where a strong charge density fluctuation of low frequency should exist. 展开更多
关键词 dusty plasma charge density fluctuation charging frequency of a dust particle
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