Light fixture heat sink with passive air flow

A light fixture, comprising:

• a light module;
• and
• a heat sink unit comprising:
• an upper heat sink having a wall section and a cavity floor, wherein the cavity floor is below a low-pressure cavity and wherein the wall section is positioned around the low-pressure cavity and the cavity floor;
• a lower heat sink attached to the upper heat sink, wherein the light module is attached to the lower heat sink;
• and
• air flow channels that provide flow paths for air that enters air intake ports of the heat sink unit to travel to the low-pressure cavity, wherein the cavity floor is located such that the air enters the low-pressure cavity from the air flow channels through one or more gaps that are between the wall section and the cavity floor, wherein first sections of the air flow channels are formed in a base section of the upper heat sink, wherein second sections of the air flow channels are formed in the wall section and wherein the base section extends outwardly from the wall section.