CST PARTICLE STUDIO里Particle Tracking和PIC solve有什么區(qū)別？

我在用CST仿真真空管，看幫助文件，2011帶了兩個(gè)例子。Electron Gun（電子槍）是用Particle Tracking計(jì)算的。而Output Cavity (workflow)的說明是This workflow example demonstrates how to build up the output cavity of a klystron for a PIC simulation。是用PIC計(jì)算的。我看了簡介。
Gun Solver & Particle Tracking
The particle tracking solver can be used to compute trajectories of charged particles within electrostatic, magnetostatic or eigenmode fields. The implemented gun-iteration enables the computation of a self-consistent electrostatic field which considers the reaction of the particle movement to the electrostatic potential distribution. As particle sources arbitrary shaped surfaces of solids can be defined. These surfaces  emit particles considering a predefined  emission model. The main task for  the solver is to calculate the particle trajectories, the self-consistent electrostatic field, the space charge distribution and the particles' current. These results appear automatically in the navigation tree after the solver run.
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PIC Solver
The PIC solver can simulate charged particles in self-consistent electromagnetic fields. Moreover static or analytic field distributions can be added to the PIC simulation. Charged particles can be emitted from arbitray surfaces or single points. Moreover electromagnetic fields can be stimulated by previously defined ports.
看兩者的說明都是計(jì)算在電場和磁場內(nèi)粒子運(yùn)動(dòng)的，那這兩者有什么區(qū)別？在實(shí)際使用的時(shí)候我怎么知道應(yīng)該用哪個(gè)？
還有一個(gè)問題是：self-consistent是什么意思?。?br />剛剛學(xué)習(xí)CST一個(gè)月不到的菜鳥求教。

PIC是自洽的吧
按照我的理解，Particle Tracking就是仿真粒子在場中的軌跡
而PIC仿真是粒子和場相互影響，粒子運(yùn)動(dòng)產(chǎn)生場，場和場相互作用，又對(duì)粒子產(chǎn)生影響。

哦，謝謝回復(fù)，大概懂了，就是說PIC是加上電場或者磁場，tracking是什么都不加的

什么都不加軌跡不就是直線了么，理解“自洽”