It is known that the eddy current need time to be built up in conductor and then can persist for a very short time.
Now we need to calculate how long time the eddy current need to be built or rise in a non-magnetic conductive metal particle that travels through a non-uniform static magnetic field with velocity v. The magnetic field length may be L, then the total travel time may be t=L/v. As the velocity is very high, might be 600m/s, now we need to know, during the time t, there is eddy current or no in the particle.
The rise times are dependent on inductances in the directions of micro-current propagation due to 2 types of emf.
1. EMF is induced by Lorentz forces acting on the electrons.
2. Faraday's EMF due to non-uniformity of the magnetic field.
You should find out directions and shapes of microcurrents inside the particle using well-known laws. After that you need to calculate corresponding 3D- distributions of EMFs. Attached paper may help you.
Then you can estimate the rise times using Ohm's law and estimations for inductances of found shapes for the conducting medium.
Article On electromagnetic induction in electric conductors
This is a diffusion problem. For simple geometries it may well have an analytical solution. In the reference frame of the particle, for particle sizes small compared to the scale length of the field non uniformity, there is just a time varying field acting on the outside of a conductor. In cylindrical geometry this is straightforward.
In the case of field homogeneity eddy currents may be induced also- due to Lorentz forces. Not so simple.
In the quasi-static approximation when the displacement/polarization currents are negligible, which I believe is the case, it is a diffusion problem with the characteristic time scale ~mu0*sigma*R**2, where R is a characteristic length scale, i.e. the particle size, and 1/(mu0*sigma) is the magnetic diffusivity.
"Diffusion is the net movement of molecules or atoms from a region of high concentration (or high chemical potential) to a region of low concentration (or low chemical potential)."
Electron concentration under EMF changes from isotropic to anisotropic case. High concentration is appeared at one particle side and low- at the other side. So, this is not a diffusion problem.
The induction equation, which governs peneration of the magnetic field into a conducting medium, reduces to a diffusion equation in the co-moving frame of reference. So, it is a diffusion problem which, by the way, describes the skin effect.
The induction equation is based on so-called "Maxwell–Faraday" equation. But it is unapplicable in "quasi-static" case which takes place as you believe. Rotary Hertz-Heaviside ("Maxwell's") equations were constructed for EM waves and have no direct experimental verification up to this time.
To check this you can try to find out an electric field in the area of pure dynamic magnetic field, or read following article:
Article Magnetodynamic waves in the air
I have no quick and easy answer for the question posed, but a closely related problem was investigated in details in:
Electromagnetic braking revisited with a magnetic point dipole moment, Sara Land, Patrick McGuire, Nikhil Bumb, Brian P. Mann, and Benjamin B. Yellen, Am. J. Pys. 84(4) 257-262 (2016), http://dx.doi.org/10.1119/1.4941099
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