A simple way to create a dust whirpool

Here we show how to create a simple picture of a dust whirpool, using the scattering media materials generated by POV Ray.

#version 3.7;
global_settings{assumed_gamma 1.0}
#default{ finish{ ambient 0.1 diffuse 0.9 }}
//--------------------------------------------------------------------------
#include "colors.inc"
#include "textures.inc"
#include "glass.inc"
#include "metals.inc"
#include "golds.inc"
#include "stones.inc"
#include "woods.inc"
#include "shapes.inc"
#include "shapes2.inc"
#include "functions.inc"
#include "math.inc"
#include "transforms.inc"
//-------------------------------------------------------------------------------------------------------<<<<
//-------------------------------------------------------------------------------------------------------<<<<
// camera ------------------------------------------------------------------
#declare CAmera_posizione = < 0.00, 1.70,-5.50>;  // vista frontale
#declare Camera_guarda_a = < 0.00, 3.2, 0.00>;
#declare CAmera_angolo = 55 ; // in gradi
//--------------------------------------------------------------------------------------------------------<<<<
camera{ /*ultra_wide_angle*/  
        location CAmera_posizione
        right     x*image_width/image_height
        angle CAmera_angolo  
        look_at   Camera_guarda_a
      }
//------------------------------------------------------------------------------------------------------<<<<<
//------------------------------------------------------------------------------------------------------<<<<<

// sole ---------------------------------------------------------------------
light_source{<1500,2500,-2500> color White*0.85}          
// cielo ---------------------------------------------------------------------

sky_sphere { pigment { gradient <0,1,0>
                       color_map { [0.00 rgb <1.0,1.0,1.0>*0.5]
                                   [0.30 rgb <0.4,0.4,1.0>*0.5]
                                   [0.75 rgb <0.4,0.4,1.0>*0.5]
                                   [1.00 rgb <1.0,1.0,1.0>*0.5]
                                 }
                       scale 3        
                     }
           } //fine del cielo
// nebbia ---------------------------------------------------------------------
fog{fog_type   2
    distance   50
    color      White*0.5
    fog_offset 0.1
    fog_alt    2.0
    turbulence 0.8}

// terreno ------------------------------------------------------------------
plane{ <0,1,0>, 0
       texture{ pigment{ color rgb <1.00,0.95,0.85>*0.5} 
                normal { bumps 0.95 scale 0.025  }
                finish { phong 0.1 }
              } //fine della trama
     } // fine del piano

//--------------------------------------------------------------------------
//--------------------------------------------------------------------------
//---------------------------- oggetto in scena ----------------------------
//--------------------------------------------------------------------------


// oggetto di diffusione della luce "tornado di polvere"

cylinder{ <0,0,0>,<0,100,0>,1.5
        pigment { rgbt 1 }
        hollow  

       interior{ //---------------------
          media{ scattering{ 1, <1,1,1> 
                             extinction  2.5 }
                 absorption rgb< 0.65, 0.89, 0.89>*2
                 // densità 1
                 density{ spiral2 8
                          turbulence 0.25
                          color_map {
                                [0.00 rgb 0.00] // bordo
                                [0.50 rgb 0.20] //
                                [1.00 rgb 1.00] // centro
                              } // fine della color_map 
                          rotate<90,0,0>
                          scale<1,0.5,1>
                        } // fine della densità 1
                 // densità 2
                 density{ cylindrical
                     turbulence 1.5
                     frequency 1
                       color_map {
                                [0.00 rgb 0.00] // bordo
                                [0.50 rgb 0.25] //
                                [0.85 rgb 1.00] //
                                [1.00 rgb 0.50] // centro
                              } // end color_map 
                     scale<1,1,1>
                     } // fine della densità 2
                
               }
            } // fine dell'interior


 rotate<0,0,-25>
 translate <   0.00, 0.15, 0.5>
}

//--------------------------------------------------------------------------
//--------------------------------------------------------------------------

Here is the picture generated by the code: