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Main Researchers

Juan Alejandro Valdivia Hepp

Phone(s): (56-2) 9787276 , (56-2) 271 2973
Departamento de Física, Facultad de Ciencias, Universidad de Chile.
Las Palmeras 3425, Ñuñoa, Santiago, Chile.

Professional Degree

  • B. S. in Physics, University of Maryland, College Park (1991).
  • B. S. in Mathematics, University of Maryland, College Park (1991).
  • B. S. in Astronomy, University of Maryland, College Park (1991).
  • M.S. in Physics, University of Maryland, College Park (1996).
  • Ph.D. in Physics, University of Maryland, College Park (1997).

Research Areas

  • Nano-clusters.
  • Complex systems.
  • Astrophysical plasma.

National and International Committees and Honors

  • The 1998 F. L. Scarf Award for best Ph.D. Dissertation, American Geophysical Union most outstanding Ph.D. dissertation in Space Physics and Aeronomy.
  • National Research Council Postdoctoral Fellowship (1997-1999), NASA, Goddard Space Flight Center, Greenbelt.
Proposal reviewer for
  • NASA, USA.
  • National Science Foundation, USA.
  • Natural Environment Research Council, USA.
  • Comisión Nacional de Investigación Científica y Tecnológica, Conicyt/Fondecyt Chile.
  • Comisión Chilena de Energía Nuclear, Chile.
  • Consejo Nacional de Investigaciones Científicas y Técnicas, Conicet, Argentina.
  • Agencia Nacional de Promoción Científica y Tecnológica, ANPyCT, Argentina.
  • Instituto de Geofísica, Universidad Autónoma de México.
  • Netherlands Organisation for Scientific Research, NWO, Netherlands.
  • Mecesup (Ministerio de Educacion, Chile).
  • Universidad de Santiago de Chile.
Paper reviewer for
  • Geophysical Research Letters.
  • Journal of Geophysical Research.
  • Radio Science.
  • Journal of Atmospheric and Solar-Terrestrial Physics.
  • Geophysical Monograph.
  • Space Science Reviews.
  • Advances of Space Research.
  • Journal of Physics D: Applied Physics.
  • Nonlinear Processes in Geophysics.
  • New Journal of Physics.
  • Physica A.
  • Earth, Planets and Space.
  • International Journal of Bifurcation and Chaos
Societies
  • American Geophysical Union (AGU).
  • American Physical Society (APS).
  • Asociación Latinoamericana de Geofísica Espacial (ALAGE).
  • Sociedad Chilena de Física.

Guided Undergraduate Thesis (Since 2006)

  • Undegraduate: A. Fritz (2005-2006), Simulación de un Horno de plasma, Universidad de los Andes, Colombia.

Projects

  • Principal Investigator (2010-2014), Conicyt Grant “Programa de Financiamiento Basal” 2009, Chile, Centro para el desarrollo de la Nanociencia y Nanotecnología.
  • Principal Investigator (2008-2009), Programa de cooperación Científica Internacional CNPq/CONICYT 2007 (Folio 2007-162), Simulación y análisis de turbulencia en plasmas en la conexión Sol-Tierra.
  • Principal Investigator (2007-2010), Fondecyt regular Grant 2007 (1070854), Chile: SELF-ORGANIZATION PROCESSES IN PLASMAS, AND ITS RELEVANCE TO THE EARTHS MAGNETOSPHERIC DYNAMICS.
  • Co-Investigator (2007-2010), Fondecyt regular Grant 2007 (1070131), Chile: THE RELEVANCE OF TURBULENCE IN THE MAGNETOSPHERE OF THE EARTH AND ITS RELATIONSHIP WITH GEOMAGNETIC STORMS AND SUBSTORMS.
  • International Researcher (2007-2011), Colciencias Grant 2007, Colombia: Center of Excellence in Complex-System Research: Centro de Estudios Interdisciplinarios Básicos y Aplicados en Complejidad (CEIBA).
  • Co-Investigator (2005-2008), Fondecyt regular Grant 2005 (1050350), Chile: Effect of finite amplitude waves on linear waves. Ion cyclotron waves in drifting multi-ion species plasmas. Stability of a magnetoplasma with cross field currents.
  • Principal Investigator (2003-2006), Fondecyt regular Grant 2003 (1030727), Chile: The relevance of global self-organization processes in plasmas and the relationship with the dynamics of the magnetotail.
  • Co-Investigator (2002-2004), Fondecyt regular Grant 2002 (1020152), Chile: Properties and dynamics of nonlinear electromagnetic beam-plasma waves, and the stability of magnetoplasma with cross-field currents.
  • Principal Investigator (2000-2002), Fondecyt regular Grant 2000 (1000808), Chile: Modeling self-organized criticality in the turbulent plasma sheet: its relation to the coherence and repeatability of the substorm phenomena.
  • Co-Investigator (1998-2000) , NASA Grant 1998, USA: The role of self-Organized Criticality in the Substorm Phenomena and its relation to Localized reconnection in the Magnetospheric Plasma Sheet.
  • Co-Investigator (1998-2000) , NASA Grant 1998, USA: Nonlinear modeling of high-latitude electrodynamics and midlatitude currents, and prediction from real-time solar wind data.

Conferences (2006 to date)

  • 2009 (November) Solidos 2009, Valparaiso, Chile.
  • 2009 (October) International Living With a Star 2009, Ubatuba, Sao Paulo, Brasil.
  • 2009 (July) The 9th International School for Space Simulations, Paris. France.
  • 2009 (June) Modern Challenges in Nonlinear Plasma Physics, Halkidiki, Greece.
  • 2009 (January) The Nonlinear Magnetosphere, Viña del Mar, Chile.
  • 2009 (January) Latin American School on Computational Materials Science, Santiago Chile.
  • 2008 (November) XVI Simposio Chileno de Fisica de la Sociedad Chilena de Física, Valparaíso, Chile.
  • 2008 (October) Informs Annual Meeting. Washington D.C, USA.
  • 2007 (November) 50a Reunión Anual de la Soc. de Biología. de Chile, Pucon, Chile.
  • 2007 (October) The World Space Environment Forum 2007, Bibliotheca Alexandrina, Egypt.
  • 2007 (August) 40 Years of Pulsars, Mcgill, Montreal, Canada.
  • 2007 (July) 4th annual meeting of the Asia Oceania Geoscience Society, Bangkok, Thailand.
  • 2007 (July) Dynamics Days Europe 2007, Loughborough University, England.
  • 2007 (June) PASI 2007 Electronic Structure and Excitations on Nanostructures, Zacatecas, Mexico.
  • 2007 (March) 51st Annual Meeting of the Biological Society, Baltimore, USA.
  • 2007 (March) American Physical Society, March Meeting, Denver, USA.
  • 2006 (December) XXIII Texas Symposium on Relativistic Astrophysics, Melbourne, Australia.
  • 2006 (November) 5ta Reunion Anual de la Sociedad Chile de Astronomia, La Serena, Chile.
  • 2006 (November) XV Reunion de la Sociedad Chilena de Fisica, Santiago, Chile.
  • 2006 (August) V Jornada de Mecánica Computacional, Concepcion, Chile.

Publications

2018
  1. D. Pastén, F. Torres, B.A. Toledo, V. Muñoz, J. Rogan, J.A. Valdivia
    Non-universal critical exponents in earthquake complex networks
    Physica A 491 (2018), 445-452
  2. R.I. González, F.J. Valencia, J. Rogan, J.A. Valdivia, J. Sofo, M. Kiwi, F. Múñoz
    Bending energy of 2D materials: graphene, MoS2 and imogolite
    RSC Adv., 2018,8, 4577-4583
  3. J.D. Meisel, O.L. Sarmiento, C. Olaya, P.D. Lemoine, J.A. Valdivia, R. Zarama
    Towards a novel model for studying the nutritional stage dynamics of the Colombian population by age and socioeconomic status
    PLoS ONE 13(2): e0191929
  4. V. Muñoz, M. Domínguez, J.A. Valdivia, S. Good, G. Nigro, V. Carbone
    Evolution of fractality in space plasmas of interest to geomagnetic activity
    Nonlin. Processes Geophys., 25, 207-216, 2018
  5. P.N. Reyes, F.J. Valencia, H. Vega, C. Ruestes, J. Rogan, J.A. Valdivia, M. Kiwi
    The stability of hollow nanoparticles and the simulation temperature ramp
    Inorg. Chem. Front., 2018,5, 1139-1144
  6. D.A. León, J.A. Valdivia, V.A. Bucheli
    Modeling of Colombian Seismicity as Small‐World Networks
    Seismological Research Letters (2018) 89 (5): 1807-1816

2017
  1. J. Wanliss, V. Muñoz, D. Pastén, B. Toledo, J.A. Valdivia
    Critical behavior in earthquake energy dissipation
    European Physical Journal B (2017) 90:167
  2. F.J. Valencia, R.I. González, J.A. Valdivia, M. Kiwi, E.M. Bringa, J. Rogan
    Inducing Porosity on Hollow Nanoparticles by Hypervelocity Impacts
    J. Phys. Chem. C, 2017, 121 (33), pp 17856–17861
  3. S. Carrasco, J. Rogan, J.A. Valdivia
    Controlling the Quantum State with a time varying potential
    Scientific Reports 7, Article number: 13217
  4. F. Castillo, A. Reisenegger, J.A. Valdivia
    Magnetic field evolution and equilibrium configurations in neutron star cores: the effect of ambipolar diffusion
    Monthly Notices of the Royal Astronomical Society 471, 507-522

2016
  1. J.A. Valdivia, B.A. Toledo, N. Gallo, V. Muñoz, J. Rogan, M. Stepanova, P.S. Moya, R.E. Navarro, A.F. Viñas, J. Araneda, R.A. López, M. Díaz
    Magnetic fluctuations in anisotropic space plasmas: The effect of the plasma environment
    Advances in Space Research 58 (2016) 2126–2133 | Published 15 Nov

2017
  1. S. Guillier, V. Muñoz, J. Rogan, R. Zarama, J.A. Valdivia
    Optimization of spatial complex networks
    Physica A 467 (2017) 465-473 | Published 1 Feb

2016
  1. M. Stepanova, J.A. Valdivia
    Contribution of Latin–American scientists to the study of the magnetosphere of the Earth. A review
    Advances in Space Research 58 (2016) 1968-1985; Published 15 Nov 2016
  2. F.J. Valencia, R.I. González, D. Tramontina, J. Rogan, J.A. Valdivia, M. Kiwi, E.M. Bringa
    Hydrogen Storage in Palladium Hollow Nanoparticles
    J. Phys. Chem. C, 2016, 120 (41), pp 23836–23841; Published 26 Sep 2016
  3. S. Carrasco, A. Varas, J. Rogan, M. Kiwi, J.A. Valdivia
    Multibody expansion of particle interactions: How many-body is a particular element in a cluster
    Phys. Rev. B 94, 075435; Published 23 Aug 2016
  4. P.D. Lemoine, J.M. Cordovez, J.M. Zambrano, O.L. Sarmiento, J.D. Meisel, J.A. Valdivia, R. Zarama
    Using agent based modeling to assess the effect of increased Bus Rapid Transit system infrastructure on walking for transportation
    Preventive Medicine 88 (2016) 39–45; Published Jul 2016
  5. D. Pastén, F. Torres, B. Toledo, V. Muñoz, J. Rogan, J.A Valdivia
    Time-Based Network Analysis Before and After the Mw 8.3 Illapel Earthquake 2015 Chile
    Pastén, D et al. Pure Appl. Geophys. (2016); Published (Web) 25 Jun 2016
  6. R.I. González, J. Rogan, E.M. Bringa, J.A. Valdivia
    Mechanical Response of Aluminosilicate Nanotubes under Compression
    J. Phys. Chem. C, 2016, 120 (26), pp 14428–14434; Published (Web) 17 Jun 2016
  7. F. Torres, J. Rogan, M. Kiwi, J.A. Valdivia
    Topological phase transition of a fractal spin system: The relevance of the network complexity
    AIP Advances 6, 055703 (2016); Published May 2016
  8. M. Ramírez, J. Rogan, J.A. Valdivia, A. Varas, M. Kiwi
    Diversity Characterization of Binary Clusters by Means of a Generalized Distance
    Zeitschrift für Physikalische Chemie, 230 (5-7), 977-989; Published 14 Mar 2016
  9. F. Castillo, B. A. Toledo, V. Muñoz, J. Rogan, R. Zarama, J. F. Penagos, M. Kiwi, J.A. Valdivia
    Spatiotemporal Complexity of a City Traffic Jam
    JCA 11.5-6, p. 381-398; Published 2016

2015
  1. F. Muñoz, A. Varas, J. Rogan, J.A. Valdivia, M. Kiwi
    Au13nAgn clusters: a remarkably simple trend
    Phys. Chem. Chem. Phys., 2015,17, 30492-30498; Published 11 Nov 2015
  2. R.A. López, R.E. Navarro, P.S. Moya, A.F. Viñas, J.A. Araneda, V. Muñoz, J.A. Valdivia
    Spontaneous electromagnetic fluctuations in a relativistic magnetized electro-positron plasma
    The Astrophysical Journal, 810:103 (6pp); Published 3 Sep 2015
  3. J. Clark, M. Kiwi, F. Torres, J. Rogan, J.A. Valdivia
    Generalization of the Ehrenfest urn model to a complex network
    Phys. Rev. E 92, 012103; Published 6 Jul 2015
  4. J. Villalobos, V. Muñoz, J. Rogan, R. Zarama, J.F. Penagos, B. Toledo, J.A. Valdivia
    Modeling a bus through a sequence of traffic lights
    Chaos 25, 073117 (2015); Published Jul 2015

2014
  1. F. Castillo, B.A. Toledo, V. Muñoz, J. Rogan, R. Zarama, J.F. Penagos, M. Kiwi, J.A. Valdivia
    City traffic jam relief by stochastic resonance
    Physica A 403 (2014) 65–70; Published 1 June 2014
  2. R.I. González, R. Ramírez, J. Rogan,J.A. Valdivia, F. Munoz, F. Valencia, M. Ramírez, M. Kiwi
    Model for Self-Rolling of an Aluminosilicate Sheet into a Single-Walled Imogolite Nanotube
    J. Phys. Chem. C, 2014, 118 (48), pp 28227–28233; Published 4 Dec 2014
  3. M. Domínguez, V. Muñoz and J. A. Valdivia
    Temporal evolution of fractality in the Earth’s magnetosphere and the solar photosphere
    Journal of Geophysical Research: Space Physics 119, 3585-3603
  4. J. Villalobos, ,V. Munoz, J. Rogan, R. Zarama, N. F. Johnson, B. Toledo, J. A. Valdivia
    Regular transport dynamics produce chaotic travel times
    Phys. Rev. E, 89, 062922
  5. R. Navarro, P. S. Moya, V. Munoz, J. A. Araneda, A. F. Vinas, J. A. Valdivia
    Solar Wind Thermal Induced Magnetic Fluctuations
    Phys. Rev. Lett, 112, 245001
  6. R. E. Navarro, J. Araneda, V. Munoz, P. S. Moya, A. F.-Vinas, J. A. Valdivia
    Theory of Electromagnetic Fluctuations for Magnetized Multi-Species Plasmas
    Phys. of Plasmas 21, '092902
  7. R. A. Lopez, P. S. Moya, V. Munoz, A. F. Vinas, J. A. Valdivia
    Kinetic transverse dispersion relation for relativistic magnetized electron-positron plasmas with Maxwell-Juttner velocity distribution functions
    Phys. of Plasmas 21, 092107

2013
  1. R. A. Lopez, F. A. Asenjo, V. Munoz, A. C.-L. Chian, J. A. Valdivia
    Self-modulation of nonlinear Alfven waves in a strongly magnetized relativistic electron-positron plasma
    Phys. Rev. E, 88, 023105

2014
  1. F. Castillo , B.A. Toledo , V. Muñoz , J. Rogan , R. Zarama , M. Kiwi, J. A Valdivia
    City traffic jam relief by stochastic resonance
    Physics A, 403, 65-70
  2. P. S. Moya, R. Navarro, A. F. Vinas, V. Munoz, J. A. Valdivia
    Weak turbulence cascading effects in the acceleration and heating of ions in the Solar Wind
    Astrophys. J. 781, 76
  3. R. A. Lopez, V. Munoz, A. F. Vinas, J. A. Valdivia
    Particle-in-cell simulation for parametric decays of a circularly polarized Alfven wave in relativistic thermal electron-positron plasma
    Phys. of Plasmas 21, 032102

2013
  1. F. Muñoz, J. Rogan, J. A. Valdivia, A. Varas, and M. Kiwi
    Binary cluster collision dynamics and minimum energy conformations
    Physica B - Condensed Matter 427, 6-84
  2. B.A. Toledo, M.A.F. Sanjuan, V. Muñoz, J. Rogan, and J.A. Valdivia
    Non-smooth transitions in a simple city traffic model analyzed through supertracks
    Commun. Nonlinear Sci. Numer. Simulat. 18, 81-88
  3. J. A. Valdivia, J. Rogan, V. Muñoz, B.A. Toledo, M. Stepanova
    The Magnetosphere as a complex system
    Adv. Space Res. 51, 1934-1941
  4. J. Rogan, A. Varas, J. A. Valdivia, and M. Kiwi
    A strategy to find minimal energy nanocluster structures
    Journal of Computational Chemistry 34, 2548–2556
  5. F. Muñoz, C. Cárdenas, J. Rogan, J.A. Valdivia, P. Fuentealba and M. Kiwi
    Ab Initio Molecular Dynamics Simulations of Ti2 on C20 Collisions and C20Ti2 Configurations
    The Journal of Physical Chemistry C 117, 4287-4291

2012
  1. C. Cárdenas, F. Muñoz, M. Muñoz, A. Bernardin and P. Fuentealba
    A new isomer of C20 and a way to a new C240
    Physical Chemistry Chemical Physics 14, 14810-14814
  2. P.S. Moya, A.F. Vinas, V. Muñoz, J.A. Valdivia
    Computational and Theoretical study of the wave-particle interaction of proton and waves
    Ann. Geophys. 30, 1361-1369
  3. R.A. López , F.A. Asenjo , V. Muñoz, J.A. Valdivia
    Parametric decay in relativistic magnetized electron-positron plasmas with relativistic temperatures
    Phys. Plasmas 19, 82104
  4. D. Pasten, V. Muñoz, B. Toledo, J. Villalobos, R. Zarama, J. Rogan, J.A. Valdivia
    Universal behavior in a model of city traffic with unequal green/red time
    Physica A 391, 5230-5243
  5. F. Asenjo, F. Borotto, A.C.L. Chian, V. Muñoz, J.A. Valdivia, E. Rempel
    Self-modulation of nonlinear waves in a weakly magnetized relativistic electron-positron plasma with temperature
    Phys. Rev. E 85, 46406
  6. M. Domínguez, V. Muñoz, J.A. Valdivia
    Thermal Effects on the Propagation of Large Amplitude Electromagnetic Waves in Magnetized Relativistic Electron-Positron Plasma
    Phys. Rev. E 85, 56416
  7. M. Kiwi, F. Muñoz, G. García, R. Ramírez, J. Rogan, J.A. Valdivia
    Nanocluster Collisions as a Way to Understand the Role of d-Shell Polarization
    European Physics Journal D 25, 2205

2009
  1. F. Asenjo, V. Muñoz, J.A. Valdivia, T. Hada
    Circularly polarized wave propagation in magnetofluid dynamics for relativistic electro-positron plasmas
    Phyics of Plasmas 16, 122108
  2. Varas, M.D. Cornejo, B.A. Toledo, V. Muñoz, J. Rogan, R. Zarama, and J.A. Valdivia
    Resonance, criticality, and emergence in city traffic investigated in cellular automaton models
    Physical Review E 80, 056108

2010
  1. F.A. Asenjo, V. Muñoz, J.A. Valdivia
    Relativistic mass and charge of photons in thermal plasmas through electromagnetic field quantization
    Physical Review E 81, 056405
  2. J. Villalobos, B.A. Toledo, D. Pasten, V. Muñoz, J. Rogan, R. Zarama, N. Lammoglia, and J.A. Valdivia
    Characterization of the nontrivial and chaotic behavior that occurs in a simple city traffic model
    Chaos 20, 013109
  3. A.C.-L. Chian, M. Han, R.A. Miranda, C. Shu, J.A. Valdivia
    The planetary-exoplanetary environment: a nonlinear perspective
    Ad. Spa. Res. 46, 472

2011
  1. F. Muñoz, J. Rogan, G. García, M. Ramírez, J.A. Valdivia, R. Ramírez and M. Kiwi
    Collisions between a single gold atom and a 13 atom gold clusters: an ab initio approach
    European Journal of Physics D, 61 87-93
  2. V. Pinto, M. Stepanova, J. A. Valdivia, E. Antonova
    Spatial distribution of the eddy diffusion coefficients in the plasma sheet during quiet time and substorms from THEMIS satellite data
    J. Geophys. Res., 116 A00I24
  3. F. Asenjo, V. Muñoz, J.A. Valdivia, S. H. Hahajan
    A Hydrodynamical model for Relativistic Spin Quantum Plasmas
    Phys. Plas., 18 012107
  4. P. Moya, V. Muñoz, J. Rogan, J.A. Valdivia
    Study of the Cascading Effect During the Acceleration and Heating of Ions in the Solar Wind
    J. of Atmos. and Solar-Terrestrial Phys 73, 1390-1397
  5. R. González, G. Garcia, R. Ramírez, M. Kiwi, J. A. Valdivia, T. Rahman
    Temperature dependent properties of 147 and 309 atom iron-gold nanoclusters
    Phys. Rev B 83 155425
  6. F. Muñoz, J. Rogan, G. Garcia, J. A. Valdivia, R. Ramírez, M. Kiwi
    The role of d-orbital polarization on Rhodium cluster collisions
    European Phys. J. D. DOI 10114
  7. V. Pinto, M. Stepanova, E. E. Antonova, J. A. Valdivia
    Estimation of the eddy-diffusion coefficients in the plasma sheet using THEMIS satellite data
    J. of Atmos. and Solar-Terrestrial Phys 73, 1472-1477

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