I need help conceptually visualizing the mechanics of an EM wave, and especially a DeBroglie type of quantum "wave". I realize that it's a probability wave, but I'm trying to extrapolate a classical image to the general idea. "Normal" force waves result from modulations and/or imbalances between competing forces on a system within the constraints of the system in question. For example, as sound waves travel through a medium, the momentum of the particles and the electromagnetic repulsion forces the waves forward into modulating high and low density crests and troughs. Water waves also occur as the particle momentum and EM repulsive forces displace the water as allowed by the competing force of gravity, producing the modulation of the wave. Tensile forces and momentum modulation in a vibrating guitar string are relatively easy to imagine. These descriptions are all obviously over simplifications, but the general ideas are intuitively easy to visualize. But what are the competing/constraining factors that produce the "wave" modulation of light or DeBroglie particle waves? Can anyone help me with an intuitive image here?