An umbrella with a space blanket, a survivor reflective blanket should be an effective shield.
Ooooh, I’m soooo afraid!
I’m not sure if the microscopic aluminized surface of one of those blankets would stand up to the energy density. The effect might be like that of popping a dinner plate with gilded decorations into a kitchen microwave oven — induction of currents with a burning of the thin metal. This is because the skin depth of the induced currents in the metal is large compared with the metal’s thickness. Kitchen grade aluminum foil on the umbrella would work better I believe. Turn said umbrella upside down and you can even focus the reflected energy back into a point! (Like sunlight through a magnifying glass which ignites a fire.)