A harmonic oscillator model is proposed to study the intensification of microwave radiation of an electrically small antenna when surrounded by a subwavelength plasma discharge. This model describes the oscillations of free electrons in a spherical plasma when it is excited by an incident electromagnetic wave. It shows that at resonance, these charge oscillations lead to a significant volume current and, thus, to an enhancement of the radiation. Depending on the electron density of the plasma, this radiation enhancement may occur in the microwave range. The proposed model is compared with the Mie scattering theory with perfect agreement when the electrical size ka of the spherical plasma remains smaller than 0.1. Despite its apparent simplicity, this model unveils the main mechanism that stands behind the intensification of microwave radiation by a subwavelength plasma discharge.

中文翻译：

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谐波振荡器模型，用于研究亚波长均匀等离子体放电对微波辐射的增强

提出了一种谐波振荡器模型，用于研究电小天线在亚波长等离子体放电包围下的微波辐射强度。该模型描述了球形等离子体中自由电子在被入射电磁波激发时的振荡。它表明，在共振时，这些电荷振荡会导致很大的体积电流，从而导致辐射增强。根据等离子体的电子密度，这种辐射增强可能发生在微波范围内。当电气尺寸为k时，将所提出的模型与Mie散射理论进行比较，并具有完美的一致性球形等离子体的λ保持小于0.1。尽管其表面上看起来很简单，但该模型仍揭示了由亚波长等离子体放电引起的微波辐射增强的主要机理。