Chapter IV: Ambient Magnetic Dipoles from "Explorations in Classical Magnetism and Contemporary Art .."

“Ambient Magnetic Dipoles: Amplified Mapping of Dipole Moments Through Analog Differentiation Techniques and Ferromagnetic Fluids” is an installation that picks up and calculates ambient magnetic dipole signatures in a two dimensional slice of a large gallery space and amplifies these signatures magnetically in a 60-gallon cubic tank of a ferromagnetic fluid and water suspension. By transplanting the physics laboratory – the equipment, electronics, and methodology – into the studio/gallery space, this work endeavors to closely integrate not just the structures of physics with a viewer’s visual aesthetic experience but also the practice of art with the practice of physical experimentation. I will first describe what exactly are “ambient dipole signatures”; second, give a non-technical overview of how this amplification process works; and finally discuss the integration of a laboratory space into the studio/gallery context.

I have explained magnetic dipoles in Chapter I. It is an “object” that produces a field quite similar to that of a common household bar or refrigerator magnet and it is considered to be the lowest order approximation of any arbitrary magnetic field in space. “Lowest order approximation” is a physics term that captures the greatest amount of information with the simplest model. A non-physics example would be that “the lowest order approximation” of a human head when drawing is a circle. My installation attempts to pick out these dipole signatures of the space and exhibits them in the 60-gallon tank.

Another analogy could be to imagine a place where the most prominent and common color there is green. Then imagine I have a camera with a filter that only picks up green. When I develop the film, I have an incomplete image of the world – an image that shows only the green. But because green is the most common color in this place, I get a fairly decent idea of what this place looks like. My apparatus serves to do the same. By picking up the lowest order magnetic signature, I hope to give a viewer an approximate rendition of the magnetic field they stand in. In fact, some biophysicists approximate neuro-electric currents in the human brain with tiny magnetic dipoles.[1] When the ambient magnetic fields of the instillation space change due to people walking through, cars driving by, or thunderstorms passing through, the viewer would be able to see the changing dipole signatures in the tank.

FIGURE I

There are sixteen two-axis magnetoresistance (MR) effect probes that detect the magnitude of the magnetic field in two perpendicular directions parallel to the floor (FIGURE I). Each of the sensor circuits is mounted on a camera tripod to evoke the idea of photography or video and also the replacement of the visual from the magnetic. They are arranged in a 4 by 4 lattice with each lattice point spaced 2-3 meters apart.  The magnetoresistance effect is a physical phenomenon that allows these probes to detect magnetic fields. Each individual sensor can measure the magnitude of the magnetic field in a specific direction. A two-axis probe contains two of these sensors that measure the field strength in two perpendicular directions. If a magnetic field is present and is also aligned in the direction of one of these sensors, the field changes the resistance of the material. Resistance describes the degree in which a material can absorb electric power. Thus, by measuring the resistance across this material, the MR sensor can output an electric signal that is proportional to how strong the magnetic field is in that given direction (FIGURE II).

FIGURE II

The signals these sixteen MR probes are then processed by a special configuration of instrumentation amplifiers and solid state relays that give an approximate description of the various dipole signatures of the space. Dipole signatures only exist when there is a specific kind of variation in the magnetic fields between certain points in space. These instrumentation amplifiers are tiny electronic devices that amplify the small variation between two signals. By setting them up in a specific way, we can figure out where and how strong these dipole signatures are.

The signals these sixteen MR probes are then processed by a special configuration of instrumentation amplifiers and solid state relays that give an approximate description of the various dipole signatures of the space. Dipole signatures only exist when there is a specific kind of variation in the magnetic fields between certain points in space. These instrumentation amplifiers are tiny electronic devices that amplify the small variation between two signals. By setting them up in a specific way, we can figure out where and how strong these dipole signatures are.

Next by implementing twelve magnetic coils controlled by a specific configuration of switches, my apparatus maps the ambient dipole signatures into the tank of ferrofluid. The tank, like the installation space, is divided into a 4 by 4 square lattice, except here, each grid line is spaced 6 inches apart, with electromagnets (or coils) positioned parallel to each grid segment to make the mathematics of the system work out. The tank is filled with a ferrofluid and water suspension.

Because ferrofluid is denser the water, when all of the coils are turned off, the ferrofluid will sink to the bottom of the tank creating a layer that is about 1 cm thick. The coils are all positioned in a plane about 2 cm above the ferrofluid. This is so that the water can cool off the coils, as they generate a substantial amount of heat, and also to prevent the coils magnetizing all of the ferrofluid in the tank.

As explained in Chapter II (and Chapter VI for a more technical treatment of ferrofluids), ferromagnetic fluid is a liquid that responds quite dramatically and quickly to applied magnetic fields. As the coils are turned on and off by the circuit that calculates dipole signatures, the ferrofluid in the tank will map out the dynamic magnetic field inside the tank generated by these coils, creating a visual approximation of both the generated magnetic field inside the tank thus in turn also the dipoles in the installation space.

Although I have given a brief overview of the apparatus, “Ambient Magnetic Dipoles” is not just the objects in the installation; it is also the act of placing the physics laboratory framework into the artistic studio and gallery context. I have chosen a more “raw” or rather a more “lab-like” aesthetic (the viewer can see all the wires, electric circuits, laboratory devices in the gallery); in a sense, this particular work is also a performance piece. Throughout the entire process, I have engaged the conception and construction of the apparatus in the same way one would conduct a proper scientific measurement including writing a computer program to run simulations and calculations, running through electronic circuit testing, and perhaps most importantly documenting everything in a lab notebook (quad ruled, 200 pages, archival, FIGURE III).

As the installation is running, daily maintenance, modification and documentation are required (like any experimental setup). In addition to the apparatus in the gallery, a lab bench is installed with the current supplies for the coils and electronics, some other experimental control devices, and daily maintenance tools (such as multimeters, soldering irons, etc.). The viewer is allowed to peruse through the lab book in addition to being able to “play” with the installation by bringing various objects into the sensor grid thus effectively transforming the passive viewer to an “experimenter”. This concludes my general, qualitative, description of the “Ambient Magnetic Dipoles” work. Although I have left out many technical details, I hope that this chapter has provided a short but clear documentation for my installation and performance. For a more quantitative and scientific treatment of my project, please read the next two optional technical chapters.

FIGURE III