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“理论预言激光足够强时可以从真空中产生正负电子对,但没有人知道是否可以实现”.本文回顾了从真空中产生正负电子对相关的理论发展,以及理论上要求的激光条件,和目前激光达到的条件:施温格推导出当准静电场达到量子电动力学关键场E_s=me~2c~3/e?=1.32×10~(16) V/cm(对应场强I_s=4.65×10~(29) W/cm~2)时,正负电子对可以从真空中产生;单束聚焦激光产生正负电子对阈值光强约为5×10~(27) W/cm~2;两束相向传输的激光同时聚焦到同一点,对应的单束光强阈值约为10~(26) W/cm~2.考虑到只要有一对正负电子产生,其在激光场作用下的级联过程将耗尽激光场能,使最高的激光场强不能高于约3×10~(26) W/cm~2.目前国际上最高激光功率是由钛蓝宝石激光经过多级啁啾脉冲放大获得,为5.13 PW,对应光强在10~(24) W/cm~2.国际上有几个大的激光项目,近几年目标是10~15 PW,远期目标百拍瓦到艾瓦.远期目标获得的光强可以产生正负电子对,但是能否实现仍然未知.
“Theory predicts that the laser can generate positive and negative electron pairs from a vacuum when the laser is strong enough, but no one knows if it can be achieved.” This paper reviews the theoretical developments related to the generation of positive and negative electron pairs from a vacuum and the theoretically required laser Conditions, and the conditions reached by the current laser: Schwinger deduces that when the quasi-electrostatic field reaches the critical field of quantum electrodynamics E_s = me ~ 2c ~ 3 / e = 1.32 × 10 ~ (16) V / cm = 4.65 × 10 ~ (29) W / cm ~ 2), the positive and negative electron pairs can be generated from the vacuum. The single-beam focused laser produces positive and negative electrons with a threshold intensity of about 5 × 10-27 W / cm ~ 2; the two laser beams transmitted toward each other at the same time focus on the same point, the corresponding single beam intensity threshold is about 10 ~ (26) W / cm ~ 2. Considering that as long as there is a pair of positive and negative electrons, which act in the laser field Under the cascade process will be depleted of laser field, the maximum laser field strength can not be higher than about 3 × 10 ~ (26) W / cm ~ 2. At present, the highest laser power is titanium sapphire laser through multilevel chirp Chirp amplification obtained for 5.13 PW, the corresponding light intensity in the 10 ~ (24) W / cm ~ 2. There are several major international laser projects in recent years, the target is 10 ~ 15 PW, the long-term goal of 100 watts To Aiwa. Far Intensity target obtained can produce electron-positron pairs, but can be achieved is still unknown.