deletions | additions       diff --git a/Introduction.tex b/Introduction.tex  index e8ad5e9..c204340 100644  --- a/Introduction.tex  +++ b/Introduction.tex 
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Radio emission from the ionosphere can produce a whistling sound in the audio frequency heard by early investigators [1]. The whistling sounds are described as groups of descending tones which are called the whistler mode. When lightning hits the southern hemisphere it produces a range of radio waves, some of which can travel along the earths magnetic field lines from the southern hemisphere to the northern hemisphere[1].These waves are called extraordinary waves .The extraordinary waves emit two solutions to the wave equation named L and R waves.The L and R refer to left and right hand circularly polarized. The waves that describe the whistling sound are R waves and they can be detected in the north but the different frequencies will travel at different speeds. For $\omega $\omega<\frac{omega_c}{2}$the  phase and group velocities increase with frequency, where ωce=eBmis the electron cyclotron frequency[1]. Due to this, the lower frequencies will arrive at the northern hemisphere later than the higher frequencies will, causing the descending tone in the whistler mode. These R waves waves that travel along the magnetic field lines are called whistler waves and these waves can only propagate for ω<ωc2 This lab seeks out to measure the dispersion relation of the whistler waves and to find the wave patterns theoretically and experimentally in the inductively coupled plasma device using Appletons equation