Viñas, A. F.Gurgiolo, C.Nieves‐Chinchilla, T.Gary, S. P.Goldstein, Melvyn2023-11-202023-11-202010-03-25A. F‐Viñas, C. Gurgiolo, T. Nieves‐Chinchilla, S. P. Gary, M. L. Goldstein; Whistler Waves Driven by Anisotropic Strahl Velocity Distributions: Cluster Observations. AIP Conf. Proc. 25 March 2010; 1216 (1): 265–270. https://doi.org/10.1063/1.3395852https://doi.org/10.1063/1.3395852http://hdl.handle.net/11603/30808TWELFTH INTERNATIONAL SOLAR WIND CONFERENCE, 21–26 June 2009, Saint‐Malo, (France)Observed properties of the strahl using high resolution 3D electron velocity distribution data obtained from the Cluster/PEACE experiment are used to investigate its linear stability. An automated method to isolate the strahl is used to allow its moments to be computed independent of the solar wind core+halo. Results show that the strahl can have a high temperature anisotropy (T⊥/ T ₗₗ ≳ 2) This anisotropy is shown to be an important free energy source for the excitation of high frequency whistler waves. The analysis suggests that the resultant whistler waves are strong enough to regulate the electron velocity distributions in the solar wind through pitch‐angle scattering.6 pagesen-USThis work was written as part of one of the author's official duties as an Employee of the United States Government and is therefore a work of the United States Government. In accordance with 17 U.S.C. 105, no copyright protection is available for such works under U.S. Law.Public Domain Mark 1.0https://creativecommons.org/publicdomain/mark/1.0/Text