Space Charge Limits in the Dae$\delta$alus DIC Compact Cyclotron

TL;DR

This paper critically examines the proposed high current extraction in the Dae$ extdelta$alus DIC compact cyclotron, showing that realistic current limits are much lower than initially claimed, due to space charge effects.

Contribution

The paper provides a realistic calculation of current limits in the DIC cyclotron, challenging previous scaling arguments and clarifying the maximum achievable beam current.

Findings

Actual current limit is about 0.2 mA.

Perveance scaling overestimates achievable current.

Maximum current is no higher than 0.5 mA.

Abstract

The Dae$\delta$alus DIC compact cyclotron is proposed to achieve an extracted current of 5 mA of singly-charged hydrogen molecules, even though unlike other compact cyclotrons, the extraction is not by stripping. The authors of the proposal consistently use perveance as a scaling argument that such high current is possible. The argument is shown to be incorrect and a realistic limit is calculated. This limit is likely about 0.2 mA and certainly no higher than 0.5 mA.