Final answer:
The Sun's magnetic field's strength and complexity are generated by the Sun's dynamo, where kinetic energy from turbulent ionized gas creates electric currents and magnetic fields.
Step-by-step explanation:
The forces that cause the Sun's magnetic field to become both stronger and more tangled include the strong nuclear force, the electromagnetic force, and gravity. The mechanism responsible for this is known as the Sun's dynamo. This dynamo is similar to the ones found in power plants on Earth, where kinetic energy is converted into electricity. However, in the Sun's case, the source of kinetic energy comes from the churning of turbulent layers of ionized gas within the Sun's core. This motion of ionized gas generates electric currents and therefore results in the creation of intricate magnetic fields.