CHIPS (Channel Hydrodynamics Integrated with Pulse Simulation): A Phenomenological WIPS Mode Propagation Code: Physical Model.

摘要

The present code (named CHIPS for Channel Hydrodynamics Integrated with Pulse Simulation) was conceived from a desire to model the WIPS bolt with a 1-d code which resolved the head-to-tail variation of parameters within each pulse. That is, the independent variables of CHIPS are z and x and pulse number rather than just z and pulse number. Due to the long time separation between pulses, the time dependent details of channel formation are not resolved. Instead, a set of formulas connect channel parameters from one pulse to the next at every specified z position. A second important reduction of the description is that a pulse is considered to be in a state of dynamic equilibrium. This allows z steps to be used which are long compared with a betatron wavelength. These two basic approximations produce a code with which a useful run takes a few minutes on the CRAY 1 computer, and parameter surveys are therefore possible. The role of the present report is to lay out the physical model of CHIPS in its initial version (completed December 1987). There are three broad domains of the physical model, with varying degrees of novelty: Beam Dynamics and Electromagnetic Field, a standard 1-d treatment assuming dynamic equilibrium; Air Chemistry, a fairly detailed model of on-axis quantities based on EMPULSE III treatment; and Channel Hydrodynamics, new formulas relate energy deposition to expansion. It must be stated that CHIPS is an initial version of a WIPS train code, and various extensions, improvements and even corrections will be apparent to the user. The code has a modular structure with sufficient comments that these changes can be readily carried out. (ERA citation 14:001514)