The centrifugal acceleration and the Y-point of the Pulsar Magnetosphere

TL;DR

This paper studies how centrifugal forces accelerate plasma in pulsar magnetospheres, revealing that efficient energy conversion occurs near the Y-point, but magnetic field opening requires additional plasma acceleration and reconnection processes.

Contribution

It provides a detailed analysis of plasma acceleration mechanisms near the Y-point, highlighting the role of magnetic reconnection and plasma dynamics in pulsar magnetospheres.

Findings

Flows near the Y-point become super fast.

Most Poynting energy converts into kinetic energy.

Magnetic field opening involves plasma acceleration and reconnection.

Abstract

We investigate the centrifugal acceleration in an axisymmetric pulsar magnetosphere under the ideal-MHD approximation. We solved the field-aligned equations of motion for flows inside the current sheet with finite thickness. We find that flows coming into the vicinity of a Y-point become super fast. The centrifugal acceleration takes place efficiently, and most of the Poynting energy is converted into kinetic energy. However, the super fast flow does not provide enough centrifugal drift current to open the magnetic field. Opening of the magnetic field is possible by the plasmas that are accelerated in the azimuthal direction with a large Lorentz factor in the closed field region. We find that this acceleration takes place if the field strength increases toward the Y-point from inside. The accelerated plasma is transferred from the closed field region to the open field region by magnetic reconnection with plasmoid emission. We also estimate the Lorentz factor to be reached in the centrifugal wind.