I'll build on David's answer (if you vote for this one, please also vote for his), since it's been a while since anyone demonstrated the excellent [shadow` package](https://mathematica.stackexchange.com/questions/43186/how-can-i-add-drop-shadows-and-specular-highlights-to-2d-graphics) on this site.

We start by defining the arrows as in the previous answer:

    myarrow[x_, y_] := Graphics[{
        Purple,
        Thickness[0.02],
        Arrowheads[.08],
        Arrow[{{x, y}, {x, y - 1.5}}],
        Black,
        PointSize[0.04],
        Point[{x, y}]
        }];
    arrows = Show[Table[myarrow[x, y], {x, 0, 7, 1}, {y, 0, -4, -2}]];

Then we create the half ellipse:

    myGreen = RGBColor[{165, 203, 149}/255];
    ellipse = Graphics[{
       myGreen,
       DiskSegment[{0, 0}, {5, 1}, {Pi, 2 Pi}]
       }, ImageSize -> 600]

![Mathematica graphics](https://i.sstatic.net/VBG8f.png)

Now we use the [shadow` package](https://mathematica.stackexchange.com/questions/43186/how-can-i-add-drop-shadows-and-specular-highlights-to-2d-graphics) to blur the ellipse:

    << shadow`

    glowingEllipse = shadow[
      ellipse,
      ellipse,
      "blur" -> 30,
      "offset" -> {0, 0},
      "color" -> myGreen,
      "outline" -> False
      ]

![Mathematica graphics](https://i.sstatic.net/vnzG1.png)

Finally, we put the arrow and the half ellipse together. We also add the gray line:

    Show[
     arrows,
     Graphics[{
       Inset[glowingEllipse, {3.5, -5.5}, {Center, Top}, {10, 2}],
       Thick, Lighter@Gray,
       Line[{{-0.8, -6}, {7.8, -6}}]
       }]
     ]

![Mathematica graphics](https://i.sstatic.net/YcWBb.png)