Minimizing Separatrix Crossings through Isoprominence

TL;DR

This paper introduces the concept of isoprominence, a property of magnetic fields that reduces transitions in guiding center orbits, and demonstrates its existence in toroidal configurations through a near-axis expansion.

Contribution

It defines isoprominence and proves its existence to all orders in a near-axis expansion for toroidal magnetic fields, highlighting key geometric features.

Findings

Isoprominence minimizes guiding center orbit transitions.

Existence of isoprominent fields is proven to all orders in a near-axis expansion.

Key geometric characteristics of isoprominent fields are described.

Abstract

A simple property of magnetic fields that minimizes bouncing to passing type transitions of guiding center orbits is defined and discussed. This property, called isoprominence, is explored through the framework of a near-axis expansion. It is shown that isoprominent magnetic fields for a toroidal configuration exist to all orders in a formal expansion about a magnetic axis. Some key geometric features of these fields are described.