We are presenting an experimental setup based on polarized light, enabling the visualization of the magnetic field of magnetic assemblies using a Hele-Shaw cell filled with ferrofluids. We have simulated the observed patterns with hypergeometric polynomials.

Jumping sun dogs are rapid light flashes changing over clouds, with some of them located close to the places of halo formation in thunder storms clouds. This paper presents an outline of some aspects that are required for understanding the jumping sun dogs, using some experiments with light scattering in complex fluids. In our analogy, we have observed the jumping laser dogs, in which the ice crystals are replaced by needlelike structures of ferrofluid, the electric field in the atmosphere is represented by an external magnetic field, and the laser beam scattered by the ferrofluid structure has the same role of the sun as the source of light scattered by the ice crystals subjected to changing electric fields in thunderstorm clouds.

We have explored some features of the complex fluids present in Earth’s atmosphere by the observation of some optical phenomena and compared them to the optical phenomena observed in gems and magnetic materials. The main feature of a complex fluid is that it contains polyatomic structures such as polymer molecules or colloidal grains. This paper includes some setups using tabletop experiments, which are intended to show concretely the principles discussed, giving a sense of how well the idealizations treated apply to the atmospheric systems. We have explored sundogs, light pillars, and the halo formation, which involve the existence of a certain structure in the atmospheric medium, resembling the structures observed in some types of gems and ferrofluids.

Observing the light passing through a thin layer of ferrofluid, we can see the occurrence of interesting effects, both in the formation patterns within the ferrofluid layer and in the dispersion of light outside that layer. This leads us to ask what the explanations associated with these effects are. In this paper, we analyze and explain the occurrence of these luminous patterns using a Ferrolens, commercially known as a Ferrocell. We present details of our experimental apparatus, followed by a discussion of some properties of light polarization and its relation to the formation of magnetic contours produced by a Ferrolens. In addition, we present the observation of a magnetochiral effect in this system. Next, we propose an application of this experiment in dynamical systems. The dynamical system is the direct observation of diffracted lines in Ferrolens, a special case of a Hele-Shaw cell containing a transparent ferrofluid subjected to various light sources.

In our previous published research we have studied the applications of the ferrolens for the observation and qualitative analysis of non-homogeneous magnetic fields. Latest developments over the last few years of the ferrolens increased multifold the sensitivity of this device allowing it to display magnetic fields as low as 10mT in strength and therefore it is possible now to observe also the homogeneous (i.e. straight parallel magnetic flux lines of uniform density in space) magnetic field existing inside air solenoids and between N-S poles of two attracting separated permanent magnets. We present and analyze herein these novel observations of homogeneous magnetic fields with the ferrolens and as a potential new application of this device. The ferrolens can now display the projected magnetic field on air from a distance without needing to be in physical contact with the field source. Experiments were carried out to demonstrate these new capabilities of the ferrolens as a nanomagnetic flux viewer, real-time physical device and scientific qualitative tool. We compare the geometry of magnetic fields of condensed matter ferromagnets with that of magnetic fields inside electrical air solenoids. Specifically, the homogeneous field between two N-S attracting magnets at a distance as well as inside air solenoids and Helmholtz coils and also the non-homogeneous total field of single dipole permanent magnets were observed using a latest generation very sensitive ferrolens. The unique feature of this magneto optic fluid thin film physical device is that it can display discrete magnetic flux lines of the macroscopic field. Also we show how the ferrolens can be used to detect qualitatively the symmetry center of a non ideal homogeneous magnetic field.