tailieunhanh - Nonlinear Optics - Appendices

Trong phụ lục này, chúng ta xem xét một thời gian ngắn các phương trình cơ bản của điện từ khi có văn bản trong hệ thống (hệ thống quốc tế, hợp lý hóa mksa) SI của các đơn vị. Chuyển đổi giữa các hệ thống SI và gaussian của các đơn vị được tóm tắt trong một phụ lục bổ sung. Mục đích của phụ lục này là thiết lập ký hiệu và không đưa ra một giải trình nghiêm ngặt của lý thuyết điện từ. . | Appendices Appendix A. The SI System of Units In this appendix we review briefly the basic equations of electromagnetism when written in the SI System International or rationalized mksa system of units. Conversion between the SI and gaussian systems of units is summarized in an additional appendix. The intent of this appendix is to establish notation and not to present a rigorous exposition of electromagnetic theory. In the SI system mechanical properties are measured in mks units that is distance is measured in meters m mass in kilograms kg and time in seconds s . The unit of force is thus the kg m sec2 known as a newton N and the unit of energy is the kg m2 sec2 known as the joule J . The fundamental electrical unit is a unit of charge known as the coulomb C . It is defined such that the force between two charged point particles each containing 1 coulomb of charge and separated by a distance of 1 meter is 1 newton. More generally the force between two charged particles of charges q1 and q2 separated by the directed distance r r r where r is a unit vector in the r direction is given by q1q2 Ĩ. F 2r. 4ne0 r 2 This result is known as Coulomb s law. The parameter 0 that appears in this equation is known as the permittivity of free space and has the value 0 X 10-12 F m. Here F is the abbreviation for the farad which is defined as 1 coulomb volt. The unit of electrical current is the ampere A which is 1 coulomb sec. The unit of electrical potential . potential energy per unit charge is the volt which is 1 joule coulomb. In the SI system Maxwell s equations have the form V X E - IB dt Vx H ID J dt In this appendix we dispense with our usual notation of using a tilde to denote time-varying quantities. 589 590 Appendices V-D p V B 0. The units and names of the field vectors are as follows E V m electric field D C m2 electric displacement B T magnetic field or magnetic induction H A m magnetic intensity P C m2 .