Although the description of the system involves the electromagnetic potential, the physical properties only depend on the electric and magneticfield-strength.
结果表明，虽然对体系的描述涉及到电磁势，但体系的物理性质只依赖于电场和磁场的强度；
2
At the Earth's surface, these tempests can be detected by changes in the strength of the Earth's magneticfield.
在地球表面，可以通过改变地球磁场强度来检测这些风暴。
3
These magnetic forces are monstrous when compared with the magneticfieldstrength of our planet — which measures in at less than 1 gauss at the Earth's surface.