# Plotting list data of cross product of field vectors

I have some experimental data points of electric Ey(t, value) and magnetic field Hz(t, value). I am trying to calculate the cross product of

CrossProduct[Last /@ Ey, Last /@ Hz]


After that, I tried to plot by

ListPlot[Transpose[{First /@ Ey, Last /@ Ey, Last /@ Hz}], Joined -> True].


But it's not working.

Ey(t,value)={{545136.47, -10299.3}, {545272.75, 12749.9}, {545136.47, -10299.3},
{545272.75, 12749.9}, {545409.04,
34182.2}, {545545.32, 52240.2}, {545681.61,
65501.5}, {545817.89, 72989.9}, {545954.18,
74243.1}, {546090.46, 69331.9}, {546226.74,
58833.2}, {546363.03, 43760.6}, {546499.31, 25462.}}

Hz(t,value)= {{435000.19, -28.325425}, {545136.47,
32.645681}, {545272.75, 89.460979}, {545409.04,
137.48363}, {545545.32, 172.95153}, {545681.61,
193.26996}, {545817.89, 197.18915}, {545954.18,
184.85647}, {546090.46, 157.74581}, {546226.74,
118.47856}, {546363.03, 70.558464}}

• It looks like some t values in Ey do not exist in Bz and vice-versa, this may contribute some issues you have yet to encounter. Nov 16, 2020 at 13:33

First, Ey has at the beginning and the end one data point more than Hz. Eliminate these:

Ey = {{545136.47, -10299.3}, {545272.75,
12749.9}, {545136.47, -10299.3}, {545272.75, 12749.9}, {545409.04,
34182.2}, {545545.32, 52240.2}, {545681.61, 65501.5}, {545817.89,
72989.9}, {545954.18, 74243.1}, {546090.46, 69331.9}, {546226.74,
58833.2}, {546363.03, 43760.6}, {546499.31, 25462.}};
Ey = Ey[[2 ;; -2]];

Hz = {{435000.19, -28.325425}, {545136.47, 32.645681}, {545272.75,
89.460979}, {545409.04, 137.48363}, {545545.32,
172.95153}, {545681.61, 193.26996}, {545817.89,
197.18915}, {545954.18, 184.85647}, {546090.46,
157.74581}, {546226.74, 118.47856}, {546363.03, 70.558464}};


Then you can calculate the cross products:

MapThread[ Cross[{0, #1, 0}, {0, 0, #2}] &, {Ey[[All, 2]], Hz[[All, 2]]}]
(*{{-361146., 0., 0.}, {-336228., 0., 0.}, {1.14062*10^6, 0.,
0.}, {4.69949*10^6, 0., 0.}, {9.03502*10^6, 0., 0.}, {1.26595*10^7,
0., 0.}, {1.43928*10^7, 0., 0.}, {1.37243*10^7, 0.,
0.}, {1.09368*10^7, 0., 0.}, {6.97047*10^6, 0., 0.}, {3.08768*10^6,
0., 0.}}*)


And plot E and H:

ListLinePlot[Ey]
ListLinePlot[{Hz}, PlotRange -> All]


• The times are misaligned, it might be helpful to show OP how to ensure these are aligned. Nov 16, 2020 at 13:32
• @Huber, I want to plot the cross product of Ey[[All, 2]], Hz[[All, 2]]}] Nov 17, 2020 at 2:53
• Use ListVectorPlot3D or ListSliceVectorPlot3D Nov 17, 2020 at 8:29