Usage

1. Add the modifier to your Asset Library or append the node group to your .blend file.
2. Create an object, separate from those objects for which the effect is to be created, to which the modifier will be applied.
3. In the modifier panel, enter the objects for the modifier to target;
   • The Heart object is used to create one or more regions of extra intensity.
   • The mesh for that object can have disconnected parts and each will be used.
   • If you do not provide a heart, set "Heart intensity" to zero (0).
4. Refine the effect in the modifier's Refinement panel;
   • Beam scale: The size of the effect volume relative to the bounding box of the target objects.
   • Density: The number of points per unit volume. Not all points become particles.
   • Particle radius: The base size of the particles, which will be modified later.
   • Rotation per frame: Particles will rotate around the modified object's Z axis, n degrees per frame.
5. Appearance
   • Material: A material of your choosing to give the particles their final appearance.
   • Tightness: Higher values lead to a more form fitting or skin-tight particle effect. 
   • Overall intensity: A fraction of the base particle size to be used for the majority of particles.
   • Heart intensity: Fraction of the base particle size to be used for particles targeting the Heart object.
     • If no Heart object is given, set this to zero (0).
   • Air intensity: A fraction of the base particle size to be used for particles farther from the target objects.
   • Stripe factor: Controls a gradient in the particle intensity;
     • Range -0.5 to 1.0
     • Value 1.0 produces columns of particles on two sides with lower intensity in the middle.
     • Value 0.0 produces an even spread of particles across the target objects.
     • Value -0.5 produces a single, central column between two lower intensity regions.
   • Noise scale: Applied to a noise texture which further modulates the scale of particles.
   • Noise offset: W axis offset of the noise texture.

Except for the Material, all properties in the Appearance panel are intended to have their values animated. I recommend also using the compositor to create glare or other effects around the particles.

Troubleshooting:

• The effect volume is just a dense column of particles:
  • Make sure that you have either specified a Heart object, or set Heart intensity to 0.0
• The beam effect rotates around the wrong point in the scene:
  • This can happen if the modified object and target object's origins are not at the same XY coordinates.
• Particles are visible in the Viewport, but don't render:
  • Make sure that you have set a Material in the modifier panel.