Asking a question about considering ion in LWFA

[IBarahimi]

I have tried to provide an input deck for LWFA, but I was confused on if I should add ion species inside on electron particles?
I mean at what condition I must add ion particle in LWFA? Below you can find my input deck
Thanks

begin:constant
lambdalaser = 1030.0 * nano

ne0 = 2.5e23
W_M = 30.0e-6 #in meter
r0 = 1.2 * 30.0e-6
re = 2.8179403229e-15

s1 =  (1.0/(pi * re * W_M * W_M))*(1.0*y/W_M)^(10) +  ne0
s2 =  1.0274e24


Wp02 = (ne0*qe*qe)/(me*epsilon0)
WL2 = (4*pi*pi*c*c)/(lambdalaser*lambdalaser)
Vg = (1-Wp02/(2*WL2)-(2*c*c)/(WL2*W_M*W_M))*c

end:constant



begin:control
dlb_threshold=1

nx = 50000 #dx=1030e-9/10  nx=4500e-6/dx
ny = 194   #dy=1030e-9/2.5  ny=80e-6/dy

t_end = 1666667 * femto

x_min = 0.0 * micro
x_max = 5100.0 * micro

y_min = -40.0 * micro 
y_max =  40.0 * micro



stdout_frequency = 100

#restart_snapshot = restart0123.sdf

end:control

	begin:boundaries
        
	bc_x_min = simple_laser
	bc_x_max = open
	bc_y_min = open
	bc_y_max = open
	
	end:boundaries
	
		begin:laser
		boundary = x_min
		lambda = lambdalaser
		intensity_w_cm2 = 3.33e18  # a0 = 1.61
		profile = gauss(y, 0, 25.48*micro)
		t_profile = gauss(time, 67.94574e-15 , 33.97287e-15)
		end:laser

		begin:laser
		boundary = x_min
		lambda = lambdalaser
		intensity_w_cm2 = 1.6e17  # a0 = 0.35
		profile = gauss(y, 0, 25.48*micro)
		t_profile = gauss(time, 3466.5893e-15 , 849.3218e-15)
		end:laser
		
	
			begin:species
			name = electron
			charge = -1.0
			mass = 1.0
			temp = 58023.0 #equal to 5 electron volt
			density = if((y lt 36.0e-6) or (y gt -36.0e-6), s1 , s2)
			npart_per_cell = 5
			end:species
			
			begin:species
			name = ion
			charge = 1.0
			mass = 1836.15
			temp = 58023.0 #equal to 5 electron volt
			density = 2.5e23
			npart_per_cell = 5
			immobile = F
			end:species
			
			begin:window
			move_window = T
			window_v_x = Vg
			window_start_time = 17000.0e-15
			bc_x_min_after_move = open
			bc_x_max_after_move = open
			end:window
			
				begin:output
				name = normal
				file_prefix = normal
				use_offset_grid=T
				dt_snapshot = 100.0 * femto
				poynt_flux = always
				grid = always
				ex = always
				ey = always
				number_density = always + species
				end:output
				
				begin:output
				  name = restart
				  file_prefix = restart
				  restartable = T	  
				  dt_snapshot = 1000.0 * femto
				end:output