PPPL-3596 is available in <a href="PPPL-3596.pdf">pdf</a> or 
<a href="PPPL-3596.ps">postscript</a> formats.

<p>
<b>Stochastic Ion Heating at the Magnetopause due to Kinetic Alfv&#233;n Waves</b>
</p>

<p>
<b>Authors:</b> Jay R. Johnson and C.Z. Cheng 
</p>

<p>
<b>Date of PPPL Report:</b> August 2001
</p>

<p>
<b>Published in:</b> Geophys. Res. Lett. <b>28</b> (December 2001) 4421-4424.</p>


<p>
The magnetopause and boundary layer are typically characterized by large amplitude transverse wave activity with freqency below the ion cyclotron frequency. The signatures of the transverse waves suggest that they are kinetic Alfv&#233;n waves with wavelength on the order of the ion gyroradius. We investigate ion motion in the presence of large amplitude kinetic Alfv&#233;n waves with wavelength the order of <FONT FACE = "SYMBOL">r</FONT FACE><sub>i</sub> and demonstrate that for sufficiently large wave amplitude (<FONT FACE = "SYMBOL">d</FONT FACE>B<FONT FACE = "SYMBOL"><sub>^</sub></FONT FACE>/B<sub>0</sub> > 0.05) the particle orbits become stochastic. As a result, low energy particles in the core of the ion distribution can migrate to higher energy through the stochastic sea leading to an increase in T<FONT FACE = "SYMBOL"><sub>^</sub></FONT FACE> and a broadening of the distribution. This process can explain transverse ion energization and formation of conics which have been observed in the low-latitude boundary layer.





</p>