needs very high energy densities with rise time of load current less than 100 ns [2]. It plays a very important role in the fields of intense radiation effect, high energy density physics, inertial confinement fusion, inertial fusion energy, material science under extreme conditions, and laboratory astrophysics [3; 4; 5], to name a few. Traditionally, a Z-pinch pulsed power driver is based on the \(\upmu\)s-class Marx-generator and pulse-forming technology. However, Marx-architecture has drawbacks such as low energy transfer efficiency, low repetition rate, and high components withstand voltage [3]. The fast linear transformer driver (FLTD) has been developed for the last 20 years which can directly generate high power pulses with rise time less than 100-ns and amplitude up to 1-MA [4]. FLTD is generally considered to be one of the most promising technologies for the next generation Z-pinch driver. In FLTD configuration, the basic building block is called \"brick\", which is composed of two film capacitors and one low-inductance gas switch connected in series. In essence, a brick is a single-stage Marx generator and can be regarded as a series-connected RLC circuit. Dozens of discharging bricks are arranged azimuthally around magnetic cores in the primary side of the FLTD cavity and are connected in parallel to a coaxial water-insulated transmission line impedance transformer in the secondary side of the FLTD cavity. To achieve synchronous triggering of bricks in the same cavity and sequential triggering of bricks in different cavities, tens of thousands of trigger signals are required in an FLTD based pulsed-power accelerator, leading to immensely complicated charging- and triggering-systems. [PERSON] et al. [6] proposed a triggering scheme based on a triggering brick and azimuthal transmission line inside the FLTD cavity, reducing complexity of the triggering system. As depicted in Figure 1, in each stage, there are 23 discharging bricks and one triggering brick packaged in the proposed FLTD cavity. Figure 2 illustrates cross sectional view of the FLTD cavity. The discharging bricks are connected to the stainless-steel cavity via the mounting brackets (items J and K in Figure 2). To improve maintainability, the cavity outer cylindrical wall in a traditional FLTD is replaced with 24-separate columns (item Q in Figure 2). Based on this triggering technique, the 4-stage series-connected FLTD with sharing common cavity shell was presented in [7]. During the design and prototyping of FLTD, it is necessary to investigate self-consistent electromagnetic (EM) fields by using numerical approaches. FLTD and Z-pinch related simulations are usually performed with equivalent circuit model [8; 9; 10; 11; 12], finite-difference time-domain (FDTD) method [13; 14; 15], finite element method (FEM) [16; 17; 18; 19; 20], and partial element equivalent circuit (PEEC) method [21; 22; 23], etc. [PERSON] et al. [8] proposed the concept of linear transformer driver (LTD) as a fast primary energy storage device for the first time and validated its output performance. [PERSON] et al. [9] presented a 2-D circuit model for simulating power flow of the induction cavity. [PERSON] et al. [10] investigated the influence of switching jitter on the output current of a 60-cavities LTD module based on the whole circuit model. [PERSON] et al. [11] developed the concept of hybrid mode LTD stage and analyzed  
Figure 1: Top-down illustration of the newly developed 1-mega-ampere (MA) single-stage fast linear transformer driver (FLTD) cavity with top lid and insulator removed. its output current with a circuit model. [PERSON] el al. [12] established a whole circuit model for the Z-800 machine and obtained the optimal load parameters. The equivalent circuit model is very efficient for the analysis of electrical performance, but it is impossible to describe detailed field distribution inside FLT induction cavity. [PERSON] et al. [13] established a 3-D model of the 1-MA LTD cavities using the LSP Suite software.