The Telescope Array (TA) cosmic rays detector located in the State of Utah in the United States is the largest ultra high energy cosmic rays detector in the northern hemisphere. The Telescope Array Low Energy Extension (TALE) fluorescence detector (FD) was added to TA in order to lower the detector's energy threshold, and has succeeded in measuring the cosmic rays energy spectrum and mass composition down to PeV energies. In this contribution we describe the measurement of the cosmic ray energy spectrum using $\sim4$ years of TALE FD data. The energy spectrum shows features consistent with the "knee" and the "second knee".
Cosmic Rays; Galactic Extra-Galactic Transition; Knee