The cathode and anode in a vacuum diode are two parallel metal plates with a gap d = 0.5 cm between them. The area of each plate is S = 10 cm². At a voltage of V = 5000 V, a current of I = 1 A flows between the cathode and the anode. Assuming that the electric field between the plates is uniform, determine the charge density depending on the distance to the cathode. Assume that the initial velocity of the electrons is zero. Is it possible to ignore the effect of their space charge on the electrons in this case?