Analysis of Biological Effect of AC-DC Electromagnetic Fields using the Lorenz Model

Analysis of Biological Effect of AC-DC Electromagnetic Fields using the Lorenz Model

Malka N. Halgamuge (The University of Melbourne, Australia), Chathurika D. Abeyrathne (The University of Melbourne, Australia) and Priyan Mendis (The University of Melbourne, Australia)
DOI: 10.4018/978-1-61692-004-3.ch002

Abstract

Electromagnetic fields (EMF) are essential to various applications directly involving humans. Fears about the biological effect of exposure to electromagnetic fields drive enormous research into this area. This research generates conflicting results, and consequently, uncertainty regarding possible health effects. This chapter studies a nonlinear Lorenz model describing interactions among charged particles and combined alternating (AC: alternating current) and static (DC: direct current) electromagnetic fields, for various combinations of frequencies, field strengths and relative angle (?) between the AC and DC magnetic fields. We investigate the effect on charged particles of three possible combinations of alternating and static electromagnetic fields: (i) AC electric field and DC magnetic field (ii) AC magnetic field and DC magnetic field (iii) AC electric field and AC and DC magnetic field. Then the behavior of the particle in these fields with different initial conditions and strong directional effects is observed when the angle between AC and DC magnetic fields is varied. The results show that the cyclotron resonance frequency is affected by charged particles’ initial position and initial velocity. Further, we observe strong effects of electric and magnetic fields on a charged particle in a biological cell with initial position and initial velocity.
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Introduction

Electromagnetic radiation can be either ionizing (ultraviolet, X-ray and gamma rays) or non-ionizing radiation (microwave, radio waves, infrared, visible light and near ultraviolet), according to the frequency or wavelength of the radiation. Generally, either excitation or ionization can take place when radiation is absorbed by tissue. Ionization arises once radiation transports adequate energy to eliminate an electron from an atom or molecule. Excitation arises when radiation excites the motion of the atoms or molecules, or when it excites an electron from an engaged orbital into a higher-energy orbital. Electromagnetic radiation which does not hold enough energy to ionize atoms or molecules is called non-ionizing radiation.

Amplitude modulated radiofrequency fields were used in early experimental work. The amplitude modulation has been recognised as a significant factor in generating biological effects. Hence, later on electric and magnetic fields were used in experiments. Theoretical models that clarify the interaction between low frequency magnetic fields and biological tissue are crucial. Several experiments indicate an enhancement of the biological effect of certain resonance frequencies (Liboff, 1987; Liboff, Rozek, Sherman, McLeod, & Smith, 1987; McLeod, Smith, Cooksey, & Liboff, 1987; Smith, McLeod, Liboff, & Cooksey, 1987). The resonance frequencies may possibly be linked to the magnitude of the local geomagnetic field (Blackman, Benane, Rabinowitz, House, & Joines, 1985; Blackman, Kinney, House, & Joines, 1989). Further, amplitude windows were found, suggesting that stronger magnetic fields do not constantly involve rigorous biological consequence (Blackman et al., 1989).

In this chapter, we analyze the biological effects of non-ionizing radiation, in particular the behavior of charged particles exposed to alternating and static electromagnetic fields in a biological cell. Investigating the biological effects of electromagnetic fields covers a broad range of disciplines: basic biology, fundamental physics and biophysics, fundamental chemistry, biochemistry and electrical engineering (Barnes, 2006). According to the AC electric and magnetic signal, the model can be linear or non-linear. Both linear and non-linear models are considered in our analysis. A previous study (Thompson et al., 1995) of a nonlinear Lorenz model describing interaction between charged particles and combined AC and DC magnetic fields investigated the different combinations of field strengths, frequencies and relative angles between AC and DC magnetic fields in a vacuum. In this chapter, we investigate the effects on charged particles in a biological cell due to three possible combinations of alternating and static electromagnetic fields. The intention of this analysis is to clarify some of the basic characteristics in terms of the simplest possible model, which includes at least the crucial elements of the interaction of charged particles exposed to all combinations of AC and DC electromagnetic fields. See Figure 1.

Figure 1.

Coordinate system: DC magnetic field, AC electric fieldand AC magnetic field. Here, DC magnetic field,, is in the verticalplane and a uniform AC electric field, , is indirection perpendicular to theplane and AC magnetic field is in direction perpendicular to the plane

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