Changes of the electron distribution functions of hot electrons during the DPR instability. Left column: Model 2M with s = 6. Right column: Model 4M with resonance s = 5. First row: the distribution at the initial state. Second row: the distribution at ω_pe t = 1000. Distributions are normalized to their maximal value. Third row: the difference of the distributions between the initial state and at ω_pe t = 1000. Red regions are with enhanced densities and blue ones are with reduced densities. Elliptical lines show the resonance ellipses for a given k-wave vector along magnetic field. Black arrows show that the ellipses shift with increasing value of k_∥ .