diff --git a/matlab/helaz_analysis.m b/matlab/helaz_analysis.m
index 550679e27c754b6770c0f4f2181d9eeaf6d57642..e623ae83b73cfaf865ffb667d77c99ea8eeb00c8 100644
--- a/matlab/helaz_analysis.m
+++ b/matlab/helaz_analysis.m
@@ -1,6 +1,5 @@
 %% HeLaZ data
 filename = 'results_00.h5';
-default_plots_options % Script to set up default plot variables
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 %% Load the data
 moment = 'Ni00';
@@ -15,98 +14,14 @@ for it = 1:numel(timeNi)
 end
 
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
-%% Plot growth rate vs t
-gammas = zeros(numel(kr),numel(kz));
-shifts = zeros(numel(kr),numel(kz));
-% Linear fit of log(Napj)
-x1    = timeNi;
-itmin = ceil(0.5 * numel(timeNi)); %Take the second half of the time evolution
-for ikr = 1:numel(kr)
-    for ikz = 1:numel(kz)
-        fit = polyfit(x1(itmin:end),log(abs(Nipj(itmin:end,ikr,ikz))),1);
-        gammas(ikr,ikz) = fit(1);
-        shifts(ikr,ikz) = fit(2);
-    end
-end
-
-FIGNAME = 'gamma_t';
-fig = figure;
-for ikr = 1:numel(kr)
-    linename = ['$k_r = ',num2str(kr(ikr)),'$'];
-    plot(kz,gammas(ikr,:),'DisplayName',linename);
-end
-TITLE  = [];
-TITLE = [TITLE,'$\eta_n=',num2str(1.0/MODEL.eta_n),'$, '];
-TITLE = [TITLE,'$\eta_B=',num2str(MODEL.eta_B),'$, '];
-TITLE = [TITLE,   '$\nu=',num2str(MODEL.nu),'$, '];
-%TITLE = [TITLE,   '$k_z=',num2str(GRID.kz),'$'];
-
-title(TITLE);
-grid on
-legend('show')
-xlabel('$t$')
-ylabel(['$|',moment,'|$'])
-
-%% Saving fig
-if SAVEFIG
-    FIGDIR = ['../results/', SIMID,'/'];
-    if ~exist(FIGDIR, 'dir')
-       mkdir(FIGDIR)
-    end
-    FIGNAME = [FIGNAME,'_Pe_',num2str(GRID.pmaxe),'_Je_',num2str(GRID.jmaxe),...
-        '_Pi_',num2str(GRID.pmaxi),'_Ji_',num2str(GRID.jmaxi),...
-        '_etan_',num2str(MODEL.eta_n),'_etaB_',num2str(MODEL.eta_B),'_nu_',num2str(MODEL.nu)];
-    FIGNAME = [FIGDIR, FIGNAME,'.fig'];
-    savefig(fig,FIGNAME);
-    disp(['Figure saved @ : ',FIGNAME])
-end
+%% Plot growth rate vs kz
+K_RICCI = 1; %% add a sqrt(1+tau) to the kperps
+ikr     = 1; %% Fix the kr value
+plot_gamma_vs_k;
 
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 %% Plot Ni00 evolution
-FIGNAME = 'Ni00_t';
-fig = figure;
-%HeLaZ results
-x1 = timeNi;
-il = 1;
-for ikr = 1:numel(kr)
-    ic = 1;
-    for ikz = 1:2:numel(kz)
-        linename = ['$k_r = ',num2str(kr(ikr)),', k_z = ', num2str(kz(ikz)),'$'];
-        y1 = abs(Nipj(:,ikr,ikz));
-        semilogy(x1,y1,...
-            'DisplayName',linename,'Color', line_colors(ic,:), 'LineStyle', '--')
-         hold on
-        semilogy(x1(itmin:end),exp(gammas(ikr,ikz)*x1(itmin:end) + shifts(ikr,ikz)),...
-            'DisplayName',[linename,' fit'],'Color', line_colors(ic,:), 'LineStyle', '-.')
-        ic = ic + 1;
-    end
-    il = il + 1;
-end
-
-TITLE  = [];
-TITLE = [TITLE,'$\eta_n=',num2str(1.0/MODEL.eta_n),'$, '];
-TITLE = [TITLE,'$\eta_B=',num2str(MODEL.eta_B),'$, '];
-TITLE = [TITLE,   '$\nu=',num2str(MODEL.nu),'$, '];
-%TITLE = [TITLE,   '$k_z=',num2str(GRID.kz),'$'];
-
-title(TITLE);
-grid on
-legend('show')
-xlabel('$t$')
-ylabel(['$|',moment,'|$'])
-
-%% Saving fig
-if SAVEFIG
-    FIGDIR = ['../results/', SIMID,'/'];
-    if ~exist(FIGDIR, 'dir')
-       mkdir(FIGDIR)
-    end
-    FIGNAME = [FIGNAME,'_Pe_',num2str(GRID.pmaxe),'_Je_',num2str(GRID.jmaxe),...
-        '_Pi_',num2str(GRID.pmaxi),'_Ji_',num2str(GRID.jmaxi),...
-        '_etan_',num2str(MODEL.eta_n),'_etaB_',num2str(MODEL.eta_B),'_nu_',num2str(MODEL.nu)];
-    FIGNAME = [FIGDIR, FIGNAME,'.fig'];
-    savefig(fig,FIGNAME);
-    disp(['Figure saved @ : ',FIGNAME])
-end
+ikr     = 1; %% Fix the kr value
+plot_Ni00_t_evolution;
 
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
\ No newline at end of file
diff --git a/matlab/plot_Ni00_t_evolution.m b/matlab/plot_Ni00_t_evolution.m
new file mode 100644
index 0000000000000000000000000000000000000000..a90162f227845f2181f8b354c5254c363e449641
--- /dev/null
+++ b/matlab/plot_Ni00_t_evolution.m
@@ -0,0 +1,44 @@
+%% Plot the time evolution of the firt ion moment
+default_plots_options % Script to set up default plot variables
+
+fig = figure;
+
+LEGEND = [];
+
+x1 = timeNi;
+
+for ikz = 1:2:numel(kz)
+
+    linename = ['$k_r = ',num2str(kr(ikr)),'$, ','$k_z = ',num2str(kz(ikz)),'$'];
+    y1 = abs(Nipj(:,ikr,ikz));
+    semilogy(x1,y1,'DisplayName',linename)
+    LEGEND = [LEGEND, linename];
+     hold on
+
+end
+
+for ikz = 1:2:numel(kz)
+
+    semilogy(x1(itmin:end),...
+        exp(gammas(ikr,ikz)*x1(itmin:end) + shifts(ikr,ikz)),...
+        'Color', 'k', 'LineStyle', '--','HandleVisibility','off')
+
+end
+
+LEGEND = [LEGEND, 'fits'];
+
+TITLE  = [];
+TITLE = [TITLE,'$\eta_n=',num2str(1.0/MODEL.eta_n),'$, '];
+TITLE = [TITLE,'$\eta_B=',num2str(MODEL.eta_B),'$, '];
+TITLE = [TITLE,   '$\nu=',num2str(MODEL.nu),'$, '];
+TITLE = [TITLE, '$(P,J)=(',num2str(GRID.pmaxe),',',num2str(GRID.jmaxe),')$'];
+title(TITLE);
+grid on
+xlabel('$t$')
+ylabel(['$|',moment,'|$'])
+
+%% Saving fig
+FIGNAME = 'Ni00_t';
+if SAVEFIG
+    save_figure;
+end
\ No newline at end of file
diff --git a/matlab/plot_gamma_vs_k.m b/matlab/plot_gamma_vs_k.m
new file mode 100644
index 0000000000000000000000000000000000000000..7393d910df3f67a8a7f59efc6ce6dcff2bcf8a0e
--- /dev/null
+++ b/matlab/plot_gamma_vs_k.m
@@ -0,0 +1,44 @@
+%Plot growth rate vs kz
+default_plots_options % Script to set up default plot variables
+% with a linear fit of the log evolution
+gammas = zeros(numel(kr),numel(kz));
+shifts = zeros(numel(kr),numel(kz));
+% Linear fit of log(Napj)
+x1    = timeNi;
+itmin = ceil(0.5 * numel(timeNi)); %Take the second half of the time evolution
+
+if K_RICCI
+    factor = sqrt(1+MODEL.tau_i);
+    fchar  = '\times(1+\tau)^{1/2}$';
+else
+    factor = 1;
+    fchar  = '$';
+end
+
+for ikz = 1:numel(kz)
+    fit = polyfit(x1(itmin:end),log(abs(Nipj(itmin:end,ikr,ikz))),1);
+    gammas(ikr,ikz) = fit(1);
+    shifts(ikr,ikz) = fit(2);
+end
+
+fig = figure;
+linename = ['$(P,J)=(',num2str(GRID.pmaxe),',',num2str(GRID.jmaxe),')$'];
+plot(factor*kz,gammas(ikr,:),'DisplayName',linename);
+
+TITLE  = [];
+TITLE = [TITLE,'$\eta_n=',num2str(1.0/MODEL.eta_n),'$, '];
+TITLE = [TITLE,'$\eta_B=',num2str(MODEL.eta_B),'$, '];
+TITLE = [TITLE,   '$\nu=',num2str(MODEL.nu),'$, '];
+%TITLE = [TITLE,   '$k_z=',num2str(GRID.kz),'$'];
+
+title(TITLE);
+grid on
+legend('show')
+xlabel(['$k_z',fchar])
+ylabel('$\gamma L_\perp/c_{s} $')
+
+%% Saving fig
+if SAVEFIG
+    FIGNAME = 'gamma_k';
+    save_figure;
+end