Papers by Nikolai Pogorelov
Pitch-angle distribution of TeV cosmic rays in the local interstellar medium
Proceedings of 38th International Cosmic Ray Conference — PoS(ICRC2023)
Explicit-implicit cruising method for computing supersonic flow past a body
USSR Computational Mathematics and Mathematical Physics, 1985
ABSTRACT
Magnetic draping, 2–3 kHz radio emissions, and constraints on the interstellar magnetic field
AIP Conference Proceedings, 2006
ABSTRACT
What Can Global Models Combined with Observations Tell Us About the Structure of the Heliosphere? (Invited)
Astrophysics and Space Science, Oct 1, 2000
We discuss the results of numerical modeling of the solar wind with the inhomogeneous interstella... more We discuss the results of numerical modeling of the solar wind with the inhomogeneous interstellar medium. The density of the plasma component in the interstellar cloud is supposed to be space periodic. The interaction pattern is shown to be highly unsteady with hydrodynamic instabilities developing on the side portion of the heliopause.
Modeling magnetic fields in the three-dimensional heliosphere
AIP Conference Proceedings, 2006
Theoretical aspects are discussed of the solar wind interaction with the local interstellar mediu... more Theoretical aspects are discussed of the solar wind interaction with the local interstellar medium (LISM) for different solar wind (SW) and space environment conditions. It is shown that charge exchange between plasma particles and interstellar neutrals is of major importance not only for geometrical scaling of the termination shock and the heliopause, but also for various asymmetries observed by the Voyager spacecraft and SOHO satellite. In essence, neutral atoms symmetrize the heliosphere, as compared with solutions based on entirely MHD models of the SW‐LISM interface. This is applicable both to east‐west asymmetries of the termination shock that can result in transverse anisotropies in fluxes of energetic charged particles, observed by Voyager 1, and to north‐south asymmetries that may explain similar anisotropies being observed now by Voyager 2 in the southern hemisphere. It is shown by numerical simulation that interplanetary magnetic field lines do intersect the termination shock multiple times for all possible orientations of the interstellar magnetic field with respect to Sun’s magnetic axis and the LISM velocity vector. However, only certain orientations and magnitudes of the interstellar magnetic field (ISMF) vector are suitable for explaining the data observed. Physical reasons are discussed that lead to deflections of the interstellar neutral hydrogen flow from the direction of propagation of neutral helium in the inner heliosheath. On the basis of numerical simulations, possibilities are investigated for deriving the orientation of the interstellar magnetic field as a function of the deflection angle. Parameters are enlisted that affect the divergence between the LISM neutral hydrogen and neutral helium velocity vectors: strength and direction of the interstellar magnetic field, and the density of the neutral hydrogen in the unperturbed LISM. It is shown that the possibility of using the SOHO SWAN experiment as an ISMF compass is not straightforward, since the heliosphere is generically asymmetric. The effects of the slow‐fast solar wind region separation in the context of the Sun’s 11‐year activity cycle are investigated. The consequences of a tilt between the Sun’s magnetic and rotational axes are analyzed. The importance of imaging the heliosheath in fluxes of energetic neutral atoms is briefly addressed.Theoretical aspects are discussed of the solar wind interaction with the local interstellar medium (LISM) for different solar wind (SW) and space environment conditions. It is shown that charge exchange between plasma particles and interstellar neutrals is of major importance not only for geometrical scaling of the termination shock and the heliopause, but also for various asymmetries observed by the Voyager spacecraft and SOHO satellite. In essence, neutral atoms symmetrize the heliosphere, as compared with solutions based on entirely MHD models of the SW‐LISM interface. This is applicable both to east‐west asymmetries of the termination shock that can result in transverse anisotropies in fluxes of energetic charged particles, observed by Voyager 1, and to north‐south asymmetries that may explain similar anisotropies being observed now by Voyager 2 in the southern hemisphere. It is shown by numerical simulation that interplanetary magnetic field lines do intersect the termination shock multiple times for...
Classical MHD shocks: theory and numerical simulation
AIP Conference Proceedings, 2005
Recent results are surveyed in the investigation of the behavior of shocks in ideal magnetohydrod... more Recent results are surveyed in the investigation of the behavior of shocks in ideal magnetohydrodynamics (MHD) and corresponding structures in dissipative/resistive plasma flows. In contrast to evolutionary shocks, a solution of the problem of the nonevolutionary shock interaction with small perturbations is either nonunique or does not exist. The peculiarity of non‐ideal MHD is in that some nonevolutionary shocks have dissipative structures. Since this structure is always non‐plane, it can reveal itself in problems where transverse perturbations do not exist due to symmetries restrictions. We discuss the numerical behavior of nonevolutionary shocks and argue that they necessarily disappear once the problem is solved in a genuinely three‐dimensional statement.
Periodic stellar wind / interstellar medium interaction
Astronomy and Astrophysics, Apr 29, 1995
Three-dimensional motion of a nonequilibrium reacting air near a body entering an equilibrium heated region
The Influence of the Interstellar Magnetic Field on the Heliospheric Interface
Solar journey: The significance of our galactic environment for the heliosphere and earth
... Nikolai V. Pogorelov Institute of Geophysics and Planetary Physics, University of California,... more ... Nikolai V. Pogorelov Institute of Geophysics and Planetary Physics, University of California, Riverside, CA 92521 [email protected] ... (2005) has been interpreted as a possible tool for determining the ISMF direction (Izmodenov, Alexashov, & Myasnikov, 2005), because the LISM ...
Numerical Modeling of Discontinuous Gas Dynamic and MHD Astrophysical Flows
Computational Fluid Dynamics 2000, 2001
... Page 176. 150 Nikolai V. Pogorelov Fig. 4. Density isolines and magnetic field lines for the ... more ... Page 176. 150 Nikolai V. Pogorelov Fig. 4. Density isolines and magnetic field lines for the purely planar cylinder. ... Not. Royal Astron. Soc. 313, 198 (2000) 8. NA Belov, AV Myasnikov: Izvestiya AN. Fluid Dynamics 34, 379 (1999) 9. NV Pogorelov: Astrophys. ...
The Effects of Global Heliospheric Asymmetries on Energetic Neutral Atom Sky Maps
The Astrophysical Journal, 2007
Nonevolutionary MHD shocks in the solar wind and interstellar medium interaction
Astronomy & Astrophysics - ASTRON ASTROPHYS, 2000
We present the study of the solar wind interaction with the super-Alfvénic magnetized interstella... more We present the study of the solar wind interaction with the super-Alfvénic magnetized interstellar medium in the controversial case when fast magnetosonic shocks are nonevolutionary, while admissible switch-on shocks cannot exist due to geometrical reasons. The flow behaviour and the accompanying shock configuration are investigated both in the two-dimensional axisymmetric and 2.5-dimensional, that is, permitting rotation around the symmetry axis, statements. General questions of the origin of nonevolutionary MHD shocks are discussed.
Comment on “On the interaction of the solar wind with the interstellar medium: Field aligned MHD flow” by R. Ratkiewicz and G. M. Webb
Journal of Geophysical Research, 2004
MHD modeling of the outer heliosphere: Numerical Aspects
COSPAR Colloquia Series, 2001
... MHD modeling of the outer heliosphere: Numerical Aspects Nikolai V. Pogorelov a, aInstitute f... more ... MHD modeling of the outer heliosphere: Numerical Aspects Nikolai V. Pogorelov a, aInstitute for Problems in Mechanics, Russian Academy of Sciences, 101-1 Vernadskii Avenue, Moscow 117526, Russia Current ... 1. DB Aleksashov, VB Baranov, EV Barsky and AV Myasnikov. ...
Ion-Neutral Coupling in the Outer Heliosphere and Beyond
AAS/AGU Triennial Earth-Sun Summit, Apr 1, 2015
Galactic cosmic ray transport in the three-dimensional heliosheath
Self-consistent Interaction of Neutrals and Plasma at Shock Waves
ABSTRACT
Detecting Neutral Atoms from Beyond the Heliopause with Interstellar Boundary Explorer
The Astrophysical Journal, 2009
Theoretical work concerning neutral atoms to be observed by the recently launched Interstellar Bo... more Theoretical work concerning neutral atoms to be observed by the recently launched Interstellar Boundary Explorer (IBEX) spacecraft has focused on neutral hydrogen atoms created by charge exchange in the inner heliosheath. In this Letter, we explore the effects of including H atoms born through charge exchange in the outer heliosheath and the nearby interstellar medium, with energies between 10 eV and ~70 eV. Although such atoms are generally not regarded as energetic neutral atoms (ENAs), they can nevertheless be observed by IBEX due to the spacecraft's orbital speed around the Sun. We find that the apparent boost in particle energy due to this motion allows IBEX to observe interstellar neutral atoms, and that the flux of atoms at the lowest energies observed by IBEX will be dominated by atoms originating from outside the heliopause. We show, using simulated data from a self-consistent model of the heliosphere, that the first two energy channels on IBEX will be dominated by outer heliosheath ENAs, and that these flux maps can, in principle, be used to deduce the asymmetry of the outer heliosphere caused by the interstellar magnetic field. The work presented in this Letter employs the simplifying assumption that radiation pressure exactly balances gravity for an H atom, and the predictions made here are only appropriate for solar minimum conditions.
Journal of Geophysical Research, 2005
The heliopause, a surface separating the tenuous hot heliosheath flow and the dense, magnetized i... more The heliopause, a surface separating the tenuous hot heliosheath flow and the dense, magnetized interstellar flow, is subject to instabilities of the Rayleigh-Taylor and Kelvin-Helmholtz types. The dynamic properties of this discontinuity is of considerable importance for understanding the neutral atom and cosmic ray filtration at the interface. Here we investigate the stability of the upwind segment of the heliopause in the presence of charge exchange collisions using both an analytic (dispersion relation) approach and a numerical model that includes the interstellar magnetic field. Linear analysis yields dispersion relations that admit imaginary solutions for a range of wave numbers, implying that the stagnation point on the heliopause is Rayleigh-Taylor unstable to small perturbations propagating parallel to the discontinuity surface. Effects of interstellar and heliosheath atoms are analyzed separately. We confirm our analytic results by performing time-dependent numerical simulations of the nonlinear development of this instability using a multifluid MHD-neutral approach. For typical solar wind and LISM conditions we obtain cyclical evolution of the upwind heliopause with a period of about 100 years. The amplitude of these oscillations is found to be dependent on the presence of hot heliosheath neutrals. We discuss the effect of a strong LISM magnetic field on the heliopause stability and possible implications of the obtained instability on the X-ray emission and cosmic ray transport in the outer heliosphere.
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Papers by Nikolai Pogorelov