Critical nucleus charge in a superstrong magnetic field: effect of screening

TL;DR

This paper investigates how superstrong magnetic fields influence the critical charge of nuclei, revealing that screening effects counteract the field's tendency to induce positron production, especially for nuclei with Z<52.

Contribution

It demonstrates the competing effects of magnetic field-induced positron production and Coulomb screening on nuclear critical charge thresholds.

Findings

Screening prevents nuclei with Z<52 from becoming critical in superstrong fields.

Stronger magnetic fields are required for nuclei with Z>52 to reach criticality when screening is considered.

Screening effect acts opposite to magnetic field in facilitating positron production.

Abstract

A superstrong magnetic field stimulates the spontaneous production of positrons by naked nuclei by diminishing the value of the critical charge Z_{cr} . The phenomenon of screening of the Coulomb potential by a superstrong magnetic field which has been discovered recently acts in the opposite direction and prevents the nuclei with Z<52 from becoming critical. For Z>52 for a nucleus to become critical stronger B are needed than without taking screening into account.