The magnetosphere of the Moon is void. But a number of areas on its surface - "spots" - retains almost white original color of lunar rocks. Something does not give the solar wind darken them equalize with other surface formations.
As it turned out, a significant role in this education plays on the border, even a very weak magnetic field, electric field significantly.
In the area of the bright spots of the lunar surface at the periphery of the generated magnetic field generated electrostatic field, repulsive particles of the solar wind to a considerable height. (Here and below, Fig. RA Bamford et al.)
It is this: scientists from the British laboratory Rutherford - Appleton conducted an experiment, which shows that even a small size and a rather weak magnetic field can form a significant electrostatic field that can effectively protect against ionizing radiation and plasma particles. It's the bright spot protected from the bombardment of the lunar surface by the solar wind.
The magnetic field in the vicinity of the bright spots, of course, there are (often caused by particle bombardment of solar wind), but is very weak, while the solar wind, going to the Moon, seriously hampered and distorted, with heights of up to 10 000 km above the surface. As it turned out, the spots create a magnetic field having a shape roughly approximate to the bladder, the edges of which an electric field. And the intensity of the latter does not depend on the size of the magnetosphere or the intensity of the magnetic field and its gradient from - vector indicating the direction of steepest increase of the field.
That is the source of the magnetic field can be arbitrarily small, and at the same time still give rise to an electric field that can stop the solar wind particles and ionizing radiation. If only the gradient was sufficient. The experiments revealed that the effect in practice: an electrostatic field reflects the plasma, even if it generates the magnetosphere was very small.
During the experiment, the plasma flowed miniature "magnetosphere": it is not repelled by magnetic and electrostatic field.
What does this mean? Firstly, the presence of effective protection against cosmic radiation, even a heavenly body without the magnetosphere (and even without the atmosphere) redefines the idea of the absolute necessity of the existence of the magnetosphere in the worlds in which the possible origin of life.
Second, if the moon someday there will be a settlement, then when they are placed in the "bright spot" radiation protection will be mainly provided by the lunar rocks.
And the most interesting: on the basis of such mechanisms can also try to build a defense crews when they travel to Mars or to any other point of the solar system, requiring a long flight.
Now, recall, storms on the sun cause astronauts to move in the most protected bays of the ISS. But during the flight to Mars, the intensity of the solar wind can be much greater than in low-Earth orbit, which would jeopardize the survival and health of the crew.
Relevant work accepted for publication in the journal Physical Review Letters.