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 Interstellar and Heliospheric Physics: People
Marco  Velli's Picture
Jet Propulsion Laboratory
M/S 169-506
4800 Oak Grove Drive
Pasadena, CA 91109

Marco Velli

Dr. Marco Velli has developed codes for the simulation of compressible magneto- hydrodynamic flows using spectral and pseudo-spectral (Fast Fourier and Tchebychev) methods, and "compact finite difference" schemes, for problems with periodic and non-periodic boundary conditions, implementing characteristic boundary conditions allowing for both reflection-free and/or incoming wave boundary conditions. These codes have been used to study diverse phenomena from the evolution of turbulence in the expanding solar wind, the 2D evolution of turbulence in a cross section of a coronal loop in the Parker scenario, to the parametric decay of large amplitude Alfven waves in a homogeneous and stratified medium and non-linear propagation of Alfven waves at magnetic x-points.

Dr. Velli has taught mechanics, electromagnetism, astrophysics, plasma physics courses at the University of Florence, and mentored 7 students for their Laurea Thesis in Florence, directed 5 PhD theses at the University of Florence and 2 at the University of Paris XI Orsay. He has been member of peer review committees for NASA research and payload proposals as well as for ESA, member of the science definition team for Solar Orbiter (2003), and is presently a member of Solar Probe science and technology definition team, responsible for drafting the Scientific Objectives and requirements. Dr. Velli was chair and main scientific editor for the international conference Solar Wind 10, Pisa, June, 2002. He has published over seventy peer-reviewed research papers involving many collaborators both in Italy and abroad, as well as invited papers and lecture notes.

  • PhD in Physics, University of Pisa, and Scuola Normale Superiore (combined degree), Pisa, Italy (1985)

Research Interests
My research area has focused on space plasma physics and solar magnetic activity with particular emphasis on
  • the stability of magnetic structures anchored in the photosphere such as coronal loops
  • wave propagation and shock formation in inhomogeneous and stratified plasmas
  • nonlinear evolution of current sheets and magnetic reconnection
  • the properties of turbulence in dynamically forced, open systems
  • wave particle interactions in the solar corona and heliosphere


Solar Probe Plus Icon Solar Probe Plus
Solar Probe Plus will study the streams of charged particles the Sun hurls into space from a vantage point where the processes that produce the solar wind actually occur.

Professional Experience
  • Jet Propulsion Laboratory - Principal Scientist (2004 - present)
  • University of Florence - Associate Professor (with tenure)in the Department of Astronomy and Space Science, (1998-2004)
  • University of St.Andrews, Scotland - Postdoctoral Research Assistant, Solar Physics group in the Department of Mathematics (1985-1989)
  • University of Florence - Research Scientist (with tenure)in the Department of Astronomy and Space Science (1993-1998)
  • Observatoire de Paris - Post-doctoral Research Fellow, ESA/NATO/Ministere de Recherche et Tecnologie in the Departement de Recherche Spatiale (1989-1993)

Selected Publications
  1. Velli, M., Einaudi, G. and Hood, A.W., "Boundary Effects on the MHD Stability of a Resistive Plasma" Astrophys. Journal 350, 418 (1990).
  2. Velli, M., "On the Propagation of Ideal, Linear Alfvén Waves in Radially Stratified Stellar Atmospheres and Winds" Astronomy & Astrophys., 270, 304 (1993).
  3. Velli, M. "From supersonic winds to accretion: comments on the stability of stellar winds and related flows" Astrophys. Journal 432, L55 (1994).
  4. Grappin, R. and Velli,M. "Waves and streams in the expanding solar wind," Journ. Geophys. Res., 101, 425 (1996).
  5. Einaudi, G., Velli, M., Politano, H. and Pouquet A. "Energy release in a turbulent Corona" Astrophys. Journal Letts., 457, L113 (1996).
  6. Liewer, P.C., Velli, M., Goldstein, B. E., "Alfven wave propagation and ion cyclotron interactions in the expanding solar wind: One-dimensional hybrid simulations" J. Geophys. Res., 106, A12, 29261 (2001).
  7. Del Zanna, L., Velli, M. and Londrillo, P. "Parametric decay of circularly polarized Alfven waves: Multidimensional simulations in periodic and open domains," Astron. & Astrophys. 367, 705 (2001).
  8. Velli, M. "Hydrodynamics of the Solar Wind Expansion," Astrophys. and SpaceScience 277, 157, (2001).
  9. Velli, M. "MHD turbulence and the heating of astrophysical plasmas", Plasma Phys. and Controlled Fusion, 45, 202 (2003).
  10. Roussev,I. I., T. I. Gombosi, I. V. Sokolov, M. Velli, W. Manchester IV, D. L. DeZeeuw, P. Liewer, G. Toth, and J. Luhmann, "A Three-Dimensional Model of Solar Wind Incorporating Solar Magnetogram Observations" Astrophys. Jour., 595, pp. L57-L61 (2003).
  11. Del Zanna L., Schaekens, E., Velli M. "Transverse oscillations in solar coronal loops induced by propagating Alfvénic pulses," Astronomy and Astophys. 431, pp. 1095-1104 (2005).
  12. Landi S., Velli M., Einaudi G. "Alfven waves and shock wave formation at X-point magnetic field configuration," Astrophysical J. 624 pp 392-401 (2005).
  13. Buchlin E., Galtier S., Velli M., "Influence of the definition of dissipative events on their statistics," Astronomy & Astrophys. 436 pp. 355-362 (2005).
  14. “Nonlinear Dynamics of the Parker Scenario for Coronal Heating”, Rappazzo A. F., Velli M., Einaudi G. & Dahlburg R. B. 2008, Astrophysical Journal 677, 1348.
  15. “Reconnection of Quasi-singular Current Sheets: The "Ideal" Tearing Mode”, Pucci, F. and Velli, M., 2014, Astrophysical Journal 780, L19.
  16. “Evolving Waves and Turbulence in the Outer Corona and Inner Heliosphere: The Accelerating Expanding Box”, Tenerani, A. and Velli, M., 2017 Astrophysical Journal, 843, 26.

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