39 citations · 172 across the 18 of their papers we have counts for
19 papers
Non-linear dynamo waves in magnetized shear flows: a candidate mechanism for the solar cycle
Uddipan Banik
Large-scale magnetic reversals in planets, stars, and accretion disks require a non-linear theory coupling the magnetic field to its sustaining flow. We derive exact non-linear sol…
Wave interference as the origin of the cyclic magnetorotational dynamo in accretion disks: insights from weakly nonlinear theory and local shearing box simulations
Uddipan Banik, Amitava Bhattacharjee, James M. Stone
Long-period cyclic reversals of the large-scale magnetic field are a prominent feature of the dynamo associated with the magnetorotational instability (MRI) in accretion disks, but…
Non-thermal particle acceleration in multi-species kinetic plasmas: universal power-law distribution functions and temperature inversion in the solar corona
Uddipan Banik, Amitava Bhattacharjee
Non-thermal power-law distribution functions are ubiquitous in astrophysical, space, and laboratory kinetic plasmas, but their origin remains unclear. A related puzzle is the tempe…
Not all cores are equal: Phase-space origins of dynamical friction, stalling and buoyancy
Shashank Dattathri, Frank C. van den Bosch, Uddipan Banik +4
Dynamical friction governs the orbital decay of massive perturbers within galaxies and dark matter halos, yet its standard Chandrasekhar formulation fails in systems with cores of…
Universal power-law distribution functions in an electromagnetic kinetic plasma: implications for the inverted temperature profile in the solar corona
Uddipan Banik, Amitava Bhattacharjee
We develop a self-consistent quasilinear theory for the relaxation of electromagnetic kinetic plasmas, and demonstrate that the mean distribution functions of both electrons and io…
Collisionless relaxation to equilibrium distributions in cold dark matter halos: origin of the Navarro-Frenk-White profile
Uddipan Banik, Amitava Bhattacharjee
Collisionless self-gravitating systems such as cold dark matter halos are known to harbor universal density profiles despite the intricate non-linear physics of hierarchical struct…
The Dipole Instability in Gravitational -body Systems: A Natural Explanation for Lopsidedness and Off-Centered Nuclei in Galaxies
Shashank Dattathri, Frank C. van den Bosch, Martin D. Weinberg +1
We explore the stability of isotropic, spherical, self-gravitating systems with a double-power law density profile. Systems with rapid transitions between the inner and outer slope…
A self-consistent quasilinear theory for collisionless relaxation to universal quasi-steady state attractors in cold dark matter halos
Uddipan Banik, Amitava Bhattacharjee
Collisionless self-gravitating systems, e.g., cold dark matter halos, harbor universal density profiles despite the intricate non-linear physics of hierarchical structure formation…
Universal non-thermal power-law distribution functions from the self-consistent evolution of collisionless electrostatic plasmas
Uddipan Banik, Amitava Bhattacharjee, Wrick Sengupta
Distribution functions of collisionless systems are known to show non-thermal power law tails. Interestingly, collisionless plasmas in various physical scenarios, (e.g., the ion po…
Pushing the Frontiers of Non-equilibrium Dynamics of Collisionless and Weakly Collisional Self-gravitating Systems
Uddipan Banik
In the standard cosmological paradigm, structure formation occurs via gravitational encounters and mergers between galaxies and dark matter halos. These collisionless self-gravitat…
Relaxation of weakly collisional plasma: continuous spectra, discrete eigenmodes, and the decay of echoes
Uddipan Banik, Amitava Bhattacharjee
The relaxation of a weakly collisional plasma, which is of fundamental interest to laboratory and astrophysical plasmas, can be described by the Boltzmann-Poisson equations with th…
A Comprehensive Perturbative Formalism for Phase Mixing in Perturbed Disks. II. Phase Spirals in an Inhomogeneous Disk Galaxy with a Non-responsive Dark Matter Halo
Uddipan Banik, Frank C. van den Bosch, Martin D. Weinberg
We develop a linear perturbative formalism to compute the response of an inhomogeneous stellar disk embedded in a non-responsive dark matter halo to perturbations like bars, spiral…
A Comprehensive Perturbative Formalism for Phase-Mixing in Perturbed Disks. I. Phase spirals in an Infinite, Isothermal Slab
Uddipan Banik, Martin D. Weinberg, Frank C. van den Bosch
Galactic disks are highly responsive systems that often undergo external perturbations and subsequent collisionless equilibration, predominantly via phase-mixing. We use linear per…
Dynamical Friction, Buoyancy and Core-Stalling -- I. A Non-perturbative Orbit-based Analysis
Uddipan Banik, Frank C. van den Bosch
We examine the origin of dynamical friction using a non-perturbative, orbit-based approach. Unlike the standard perturbative approach, in which dynamical friction arises from the L…
A Self-Consistent, Time-Dependent Treatment of Dynamical Friction: New Insights regarding Core Stalling and Dynamical Buoyancy
Uddipan Banik, Frank C. van den Bosch
Dynamical friction is typically regarded a secular process, in which the subject ('perturber') evolves very slowly (secular approximation), and has been introduced to the host over…
A Fully General, Non-Perturbative Treatment of Impulsive Heating
Uddipan Banik, Frank C. van den Bosch
Impulsive encounters between astrophysical objects are usually treated using the distant tide approximation (DTA) for which the impact parameter, , is assumed to be significantl…
Constraining the mass density of free-floating black holes using razor-thin lensing arcs
Uddipan Banik, Frank C. van den Bosch, Michael Tremmel +5
Strong lensing of active galactic nuclei in the radio can result in razor-thin arcs, with a thickness of less than a milli-arcsecond, if observed at the resolution achievable with…
Exact results in Floquet coin toss for driven integrable models
Utso Bhattacharya, Somnath Maity, Uddipan Banik +1
We study an integrable Hamiltonian reducible to free fermions which is subjected to an imperfect periodic driving with the amplitude of driving (or kicking) randomly chosen from a…
Self-gravitating fluid systems and galactic dark matter
Uddipan Banik, Dipanjan Dey, Kaushik Bhattacharya +1
We study gravitational collapse with anisotropic pressures, whose end stage can mimic space-times that are seeded by galactic dark matter. To this end, we identify a class of space…