Hari Ramachandran received his B.Tech. from IIT Bombay in 1982 and his Ph.D. from the University of California at Berkeley, both in Electrical Engineering. He was a research scientist in the Physics Department at the University of California, Los Angeles for five years before returning to India. He was a scientist at the Institute for Plasma Research, Gandhinagar, from 1993 till 2001 and joined IIT Madras in Nov 2001.

Teaching

EC 301: Electromagnetic Fields (once a year)

EC 541: Introduction to Fiber Optic Technology (even semesters)

EC 205: CAD Laboratory (odd semesters)

Microwave Lab in charge.

Research Interests

Optical Link Design and Planning

The tenet group has a great deal of experience in the development of Access level networking systems. This strength lies in the group's expertise in all the related areas of the technology, including the optical layer, the electronic subsystems, network management systems and protocols. My own interests are in the area of the optical physical layer, including both access links and backbone link design.

Nonlinear Optics

Modern optical systems exhibit a variety of interesting phenomena, many of these nonlinear in nature. My interests are mainly in the areas of

• Optical beam propagation in turbulent media, as occurs in terrestrial optical links.
• The interaction between nonlinearity and dispersion.
• Solitary wave propagation (ie, solitons) in optical fibres.

Computational Optics

We are in the process of developing inhouse a full set of numerical tools for the investigation of optical communication problems. These include

• A Beam Propagation Method code to simulate the propataion of waves in complex geometries.
• A Finite Difference Time Domain code to simulate the transient effects on optical pulses when they encounter opto-electronic devices.
• A Physical Layer Design tool, to study the interaction between different aspects of link design. This is intended to become a pedagogical tool for introducing students to the complex world of the optical layer.

Edge Plasma Physics

Plasma Systems are notoriously complex, and never more so than in the edge. A large part of my work has related to understanding the behaviour of plasmas in the sheath and presheath. The goals of my research are to understand better some of the following:

• The nature of the ionacoustic wave in the sheath and presheath. To identify particle and energy transport mechanisms that might be unique to this region.
• The nature of the particle distribution function near the sheath region.
• The proper forms of fluid equations that are valid in the sheath and presheath.
• The sheath-presheath interface.

Computational Plasma Physics

I am developing a particle simulation code to focus on sheath and presheath physics. Issues that have already been investigated include the identification of the sheath and presheath about a dust particle, study of wave fluctuations in an afterglow plasma, the effect of magnetic fields on plasma accretion, etc.