Watching a lightning strike is interesting. Photographs of lightning strikes have shown leaders that appear just before the discharge occurs. These leaders seem to develop downwards from the underside of the cloud in leaps of about 150 feet.
They continue to extend toward the ground until, when several hundred feet from the ground, streamers begin to rise from the ground toward the leaders.
When the leaders and streamers connect, the ionized path formed provides the path for the lightning strike.
If we could prevent the leaders and streamers from making contact we might prevent lightning strikes.
Aircraft have what are known as wicks on the trailing edges. These wicks serve the same purpose as the lightning rods on the top of radio towers. They allow the aircraft to discharge itself continually as it flies.
In the case of the lightning rod, the sharper the point the better the lightning rod works.
As the diameter of a conductor decreases, the voltage gradient increases toward the point.
When the voltage at the end of the rod is sufficiently high it will bleed-off some of the induced lightning charge on the ground, streamers will be reduced or eliminated and the likelihood of a lightning strike is reduced.
A corona develops at the tip of the rod, which sometimes can be seen.