Magetic field due to straight current wire

[el_greco]

Homework Statement

We have a system of cylindrical coordinates (r,φ,z) and a straight electrical current wire along the z axis. The objective is to create a MATLAB plot of the magnetic field due to this current wire.

Homework Equations

Ampere's law gives us that B=m0*I/2πr for that current wire, for any given r (perp distance from the z axis).

The Attempt at a Solution

As a vector, this is Bφ, since the right hand grip rule tells us that the magnetic field lines follow the four right hand fingers at the φ direction, when the thumb shows the electrical current. So now I just want to plot this Bφ for a few r lines, for φ=0 to 2π, ie to obtain a few circles around this wire... Any idea how? :S

 

[Jhero]

Hello,

Thank you for sharing your approach to solving this problem. Your understanding of Ampere's law and the right hand grip rule is correct. To create a MATLAB plot of the magnetic field due to the current wire, you can use the "quiver" function. This function plots vectors at specified points in the coordinate system.

First, you will need to define the values of r and φ for the points at which you want to plot the magnetic field. For example, you can use the "linspace" function to create a vector of equally spaced values for r, and the "meshgrid" function to create a grid of values for φ.

Next, you can use the formula B=m0*I/2πr to calculate the magnitude of the magnetic field at each point. Since the magnetic field is in the φ direction, you can use this value as the y-component of the vector, and set the x-component to 0. Then, use the "quiver" function to plot the vectors at the specified points.

I hope this helps. Let me know if you have any further questions. Good luck with your plot!