Constraining small scale magnetic fields through plasma lensing: Application to the Black widow eclipsing pulsar binary

Understand

In regions with strongly varying electron density, radio emission can be magnified significantly by plasma lensing.

• In the presence of magnetic fields, magnification in time and frequency will be different for two circular polarizations.
• We show how these effects can be used to measure or constrain the magnetic field parallel to the line of sight, $B_\parallel$, as well as its spatial structure, $\sigma_{B_\parallel}$, in the lensing region.
• In addition, we discuss how generalized Faraday rotation can constrain the strength of the perpendicular field, $B_\perp$.