對於電磁波而言，在非均勻電漿體中，模轉換的過程是重要的能
量吸收機制之一。電磁波會在模轉換層經由模轉換過程轉移能量給靜
電波，靜電波在截止層則因緩慢的群速度使得震幅增大。非線性模轉
換理論的統御方程式精確到二階，其滯留流場與滯留磁場是共生共滅
的。靜電波放大了模耦合的效應產生電場之旋度的滯留分量，驅動渦
流而得到滯流磁場。我們利用有限時域差分法模擬出在雷射光的強度
為O(10^19 ) watt / cm^2情形下，滯留磁場強度可達幾百個百萬高
斯。高頻波可由模耦合機制產生，並穿透至高密度區域。靜電波改變
了電子在平衡狀態時的密度，產生密度氣泡區域，離子則藉由庫
侖爆炸加速至幾百萬個電子伏特的能量。該能量足以擊碎慣性約束核
融合靶材並產生核融合反應。

Mode conversion process is an important energy absorption mechanism of the electromagnetic waves in an inhomogeneous plasma. An electromagnetic (EM) wave at the mode conversion layer transfers its energy to the electrostatic (ES) wave whose amplitude can be greatly enhanced due to its slow group velocity and the nearby cut off layer. The mode conversion efficiency reaches up to 50%~60% at a proper incident angle. The governing equations are accurate to the second order in the nonlinear theory of mode conversion. The localized flow and DC magnetic field are synonymous. The ES wave enhances mode coupling to produce DC component of the curl of the electric field that drives vorticity to yield DC magnetic field. No DC magnetic field exists if ES wave is absent. Our finite difference time domain simulation shows that the DC magnetic field is about hundreds of mega-gauss at O(10^19 ) watt / cm^2 laser power. High harmonic waves are generated by the nonlinear mode-mode coupling mechanism which can penetrate into the high density region. The ES wave modulates electron equilibrium density to produce electron density bubble and ions can be accelerated to MeVs through Coulomb explosion enough to fragment laser fusion pellet target but can also yield fusion process.

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