The sun is a nuclear furnace that constantly boils off a gas-like mixture of charged sub-atomic particles, electrons, and protons (ions).   This zoo of charged particles is called a "plasma". The plasma state is often referred to as the fourth state of matter. Solar flares, coronal mass ejections (CME), and coronal holes, which occur sporadically, increase the output of these particles.  Therefore, the particles continuously flow outward from the sun with variable intensity toward the earth.
After the plasma particles are ejected from the sun, they travel outward in all directions.  The plasma particles along with the sun's magnetic field travel together as a " solar wind".  The plasma particles hold the sun's magnetic field and forces it to travel along with the solar wind in what scientists refer to as the "frozen-in" condition.  The solar wind drags along the solar magnetic field in gigantic spirals. Such changes in the Interplanetary Magnetic Field (IMF) are encountered by the Earth. Changes in the direction of the IMF relative to the Earth's northern axis can cause auroral activity.
	Image produced by Air Force Geophysics Laboratory
The average flow of solar wind particles covers the distance to Earth, some 150 million kilometers (93 million miles), in approximately three to six days depending on its velocity.