Magnetic field and Skin Effect

I have been trying to understand the field theory from the basics and have come across a few things I have not understood a few things clearly:

1. The magnetic field strength is maximum at the center of the conductor and decreases with an increase in the distance from the center. I understand this mathematically, i.e. the field strength is inversely proportional to the distance as per the mathematical relation, but I don't understand the physics behind it.

2. In the book "RF Circuit Design" by Chris Bowick, he says that "As the frequency is increased, an increased magnetic field at the center of a conductor presents increased impedance to the charge carriers, thus decreasing the current density at the center of the conductor and increasing the current density around it perimeter." My question is, why would an increased magnetic field strength provide impedance to the movement of charge carriers as it does at the center of the conductor.

I'd be grateful if someone could throw some light on this. Thanks.