中文摘要：

为提供一个统一的参考标准，将不同口径电磁轨道炮的研究成果联系起来，借鉴传统火炮内弹道研究方法，通过描述电磁轨道炮发射过程微分方程组，以及电枢与轨道电磁力解析分析，分别从宏观层面和微观层面考察了电磁轨道炮的内弹道过程。结果表明，电磁轨道炮的电磁场、应力场和温度场不由电流大小或口径大小单独决定，而是有由它们的比值即电流线密度决定。电流线密度平方与轨道压力、弹底压力、轨道间磁压力、轨道温度成正比，电流线密度可以反映电磁轨道炮的内膛压力大小。提出以电流线密度作为电磁轨道炮的核心参数，且比照传统火炮内弹道学参数的命名，电流线密度可以看作是电磁轨道炮的“膛压”。对大、小口径电磁轨道炮发射过程模拟计算对比表明，以电流线密度作为表征量，可以有效联系起不同口径电磁轨道发射装置上相关参数的变化规律。

英文摘要：

In order to find a universal parameter that can relate the researches of electromagnetic （EM） railguns with dif- ferent calibers, taking the tradition interior ballistic theory into consideration, we investigated the interior ballistic of railgun from aspects of both microcosmic and macrocosmic, by demonstrating the differential equations of railgun launch process and analytically analyzing the EM forces in railgun. Analysis shows that the magnetic flux density, stress, rail stress, and temperature fields depend on not current or caliber separately, but the ration of current to caliber, namely, the linear current density. Meanwhile, the square of linear current density is linearly proportional to rail stress and projectile pressure, and it represents the electromagnetic pressure in railgun. It is proposed that linear current density is a key para- meter of railgun, which can be considered as the bore pressure of railgun, referencing the similar idea in interior ballistic theory. Comparison between launch simulation of railguns with different calibers indicates that, using linear current den- sity as the character parameter, the patterns of parameters in railgun with different calibers can be effectively connected.