2,389 research outputs found
Electrostatic Structures in Space Plasmas: Stability of Two-dimensional Magnetic Bernstein-Greene-Kruskal Modes
Electrostatic structures have been observed in many regions of space plasmas,
including the solar wind, the magnetosphere, the auroral acceleration region,
and in association with shocks, turbulence, and magnetic reconnection. Due to
potentially large amplitude of electric fields within these structures, their
effects on particle heating, scattering, or acceleration can be important. One
possible theoretical description of some of these structures is the concept of
Bernstein-Greene-Kruskal (BGK) modes, which are exact nonlinear solutions of
the Vlasov-Poisson system of equations in collisionless kinetic theory. BGK
modes have been studied extensively for many decades, predominately in one
dimension (1D), although there have been observations showing that some of
these structures have clear 3D features. While there have been approximate
solutions of higher dimensional BGK modes, an exact 3D BGK mode solution in a
finite magnetic field has not been found yet. Recently we have constructed
exact solutions of 2D BGK modes in a magnetized plasma with finite magnetic
field strength in order to gain insights of the ultimate 3D theory [Ng,
Bhattacharjee, and Skiff, Phys. Plasmas 13, 055903 (2006)]. Based on the
analytic form of these solutions, as well as Particle-in-Cell (PIC)
simulations, we will present numerical studies of their stability for different
levels of background magnetic field strength.Comment: Submitted to AIP Journal Proceedings for "Tenth Annual International
Astrophysics Conference
Karakterisasi Kutu Kebul (Bemisia Tabaci) Sebagai Vektor Virus Gemini Dengan Teknik Pcr-rapd
Characterization of whitefly (Bemisia tabaci) as geminivirus vector based on RAPD-PCR. The variation of whitefly was performed by the appearance of population having diferent DNA sequence. PCR-RAPD and dendogram was expected to be used to investigate the variation of whitefly in Sumatera. Morphological observation on the whitefly colleted from field area showed that the geminivirus-transmitting vector was Bemisia tabaci with varied population. Based on PCR-RAPD and dendogram analysis in Sumatera, it was known that Bemicia tabaci had a high variation both intra and inter field area
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