In the following simulation, click the add loop button to increase the number of loops in the solenoid. The arrows that appear represent the direction of the magnetic field at that point in space. If you click and hold within the white space, a yellow text box will appear with the (x, y) coordinates of the cursor, and the strength of the magnetic field at that point. If you double click within the white space, the applet will draw the magnetic file line through the point where you double clicked.

Solenoid