I understand the solar wind impacts and sputters the surface of Mercury's north pole due to it's magnetic field deflecting it around the planet.
Maybe not a proper answer, but:
The measurements by MESSENGER spacecraft has shown that Mercury's magnetic field is tilted:
Here is a 2017 paper that summarizes recent discoveries.
MESSENGER magnetometer data show that Mercury’s magnetic field is not only exceptionally weak but also has a unique geometry. The internal field resembles an axial dipole that is offset to the North by 20% of the planetary radius.
So, same as on Earth amd most other planets, Mercury's magnetic poles do not coincide with rotation poles.
If your question is about the origin of ice deposits at Mercury permanently-shadowed craters, I've found a couple of links:
As I remember, solar wind was considered too as a source of hydrogen for water ice, especially for the Moon. But looks like the meteor/comet bombardment is evaluared as most probable source of the ice on Mercury currently.