Note to users. If you're seeing this message, it means that your browser cannot find this page's style/presentation instructions -- or possibly that you are using a browser that does not support current Web standards. Find out more about why this message is appearing, and what you can do to make your experience of our site the best it can be.

Science 8 May 2009:
Vol. 324. no. 5928, pp. 729 - 730
DOI: 10.1126/science.1172878
Prev | Table of Contents | Next

Perspectives

Planetary Science:

The Origin of Plasmaspheric Hiss

Ondrej Santolík1,2 and Jaroslav Chum1

The role of electromagnetic waves in shaping the space environment around our planet has been studied since the early 1960s (1, 2). Initial analysis of these waves at audible frequencies consisted of playing the recorded data through a loudspeaker. The historical terminology in this field thus resembles an experimental musical score where we can encounter whistlers, noise, hiss, and chorus. On page 775 of this issue, Bortnik et al. (3) invite us to this world of "space sound." On the basis of measurements by NASA's THEMIS (Time History of Events and Macroscale Interactions during Substorms) spacecraft mission, the authors describe two types of natural electromagnetic waves: chorus and plasmaspheric hiss. They show that plasmaspheric hiss can be interpreted as arising from transformed chorus waves, thus providing important clues as to its origin.

1 Institute of Atmospheric Physics, Prague, Czech Republic.
2 Charles University, Faculty of Mathematics and Physics, Prague, Czech Republic.

E-mail: ondrej.santolik{at}mff.cuni.cz

Read the Full Text

To Advertise     Find Products

Science. ISSN 0036-8075 (print), 1095-9203 (online)