微波谐振腔运动时电磁场的能量和动量

Energy and Momentum of Electromagnetic Fields of Microwave Resonant Cavity in Motion

依据电磁场的相对论变换,计算了矩形微波谐振腔匀速运动时电磁场的能量和动量。初步计算的结果表明:电场方向平行于谐振腔运动方向的波模(0,n,p)的电磁场的(一个周期平均)能量和动量完全类比于运动粒子的相对论能量和动量;但电场方向垂直于谐振腔运动方向的波模(m,n,0)的电磁场的(一个周期平均)能量和动量完全不同于运动粒子的相对论能量和动量。因此,当谐振腔的载体作高速机动时,两种波模的电磁场在相关电路中诱发的电扰动将不同。

According to the relativistic transformation for electromagnetic fields,a calculation for energy and momentum of electromagnetic fields for microwave rectangular resonant cavity in uniform motion is given.The result shows that the energy and momentum（averaged over a period）of electromagnetic fields for the mode（0,n,p）,of which the direction of electric field is parallel to the direction of the motion of resonant cavity,is completely analogous to the relativistic energy and momentum of a moving particle.However,the energy and momentum（averaged over a period）of electromagnetic fields for the mode（m,n,0）,of which the direction of electric field is perpendicular to the direction of the motion of resonant cavity,is completely different with the relativistic energy and momentum of a moving particle.Therefore,when the electromagnetic fields of the two modes respond a sharp change of the motion of cavity＇s carrier,the electrical turbulences induced in correlative circuit by the responding are different.