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Coherent radio emission in pulsars is excited due to instabilities in a relativistically streaming non-stationary plasma flow, which is generated from sparking discharges in the inner acceleration region (IAR) near the stellar surface. A…

High Energy Astrophysical Phenomena · Physics 2020-06-10 Rahul Basu , Dipanjan Mitra , George I. Melikidze

The analysis of X-ray observations suggest an ultrastrong ($B\gtrsim 10^{14} \,{\rm G}$) surface magnetic field at the polar cap of pulsars (Szary, 2013). On the other hand, the temperature of the polar caps is about a few millions Kelvin.…

High Energy Astrophysical Phenomena · Physics 2015-06-23 Andrzej Szary , George Melikidze , Janusz Gil

Despite the fact that pulsars have been observed for almost half a century, many questions have remained unanswered. We use the analysis of X-ray observations in order to study the polar cap region of radio pulsars. The size of the hot…

High Energy Astrophysical Phenomena · Physics 2013-04-19 Andrzej Szary

A novel scheme has been developed to show that the observed phase behaviour associated with subpulse drifting from two pulsars, J1034$-$3224 and J1720$-$2933, can be used to obtain the magnetic field configuration in the partially screened…

High Energy Astrophysical Phenomena · Physics 2023-05-24 Rahul Basu , Dipanjan Mitra , George I. Melikidze

The subpulse drifting phenomenon in pulsar radio emission is considered within the partially screened inner gap model, in which the sub-Goldreich-Julian thermionic flow of iron ions or electrons coexists with the spark-associated…

Astrophysics · Physics 2008-11-26 Janusz Gil , George Melikidze , Bing Zhang

The radio emission in many pulsars show sudden changes, usually within a period, that cannot be related to the steady state processes within the inner acceleration region (IAR) above the polar cap. These changes are often quasi-periodic in…

High Energy Astrophysical Phenomena · Physics 2021-06-09 U. Geppert , R. Basu , D. Mitra , G. Melikidze , M. Szkudlarek

We examined a model of partially screened gap region above the polar cap, in which the electron-positron plasma generated by sparking discharges coexists with thermionic flow ejected by the bombardment of the surface beneath these sparks.…

Astrophysics · Physics 2009-11-11 Janusz Gil , George Melikidze , Bing Zhang

A non-stationary polar gap model first proposed by Ruderman & Sutherland (1975) is modified and applied to spark-associated pulsar emission at radio wave-lengths. It is argued that under physical and geometrical conditions prevailing above…

Astrophysics · Physics 2009-10-31 Janusz Gil , Marek Sendyk

Observations of the thermal X-ray emission from old radio pulsars implicate that the size of hot spots is much smaller then the size of the polar cap that follows from the purely dipolar geometry of pulsar magnetic field. Plausible…

High Energy Astrophysical Phenomena · Physics 2012-07-20 Andrzej Szary , George Melikidze , Janusz Gil

We report on the first self-consistent multidimensional particle-in-cell numerical simulations of non-homogeneous pair discharges in polar caps of rotation-powered pulsars. By introducing strong inhomogeneities in the initial plasma…

High Energy Astrophysical Phenomena · Physics 2024-09-25 Alexander Chernoglazov , Alexander Philippov , Andrey Timokhin

We consider the problem of the thermal X-ray radiation from the hot polar cap of radio pulsars showing evidence of \EB subpulse drift in radio band. In our recent Paper I, using the partially screened gap (PSG) model of inner acceleration…

Astrophysics · Physics 2008-11-26 J. Gil , G. I. Melikidze , B. Zhang

The heating of the real polar cap surface of radio pulsars by the bombardment of ultra-relativistic charges is studied. The real polar cap is a significantly smaller area within or close by the conventional polar cap which is encircled by…

High Energy Astrophysical Phenomena · Physics 2020-07-20 Maciej Sznajder , Ulrich Geppert

Thermal radiation from hot polar caps is examined in radio pulsars with drifting subpulses. It is argued that if these subpulses correspond to sparking discharges of the inner acceleration region right above the polar cap surface then a…

Astrophysics · Physics 2007-05-23 Janusz Gil , George Melikidze , Bing Zhang

The classical vacuum gap model of Ruderman & Sutherland, in which spark-associated subbeams of subpulse emission circulate around the magnetic axis due to the EB drift, provides a natural and plausible physical mechanism of the subpulse…

Astrophysics · Physics 2009-11-07 Janusz Gil , George I. Melikidze , Ulrich Geppert

The problem of formation of the inner vacuum gap in neutron stars with ${\bf\Omega}\cdot{\bf B}<0$ is considered. It is argued by means of the condition $T_i/T_s>1$, where $T_i$ is the melting temperature of surface $^{56}_{26}$Fe ions and…

Astrophysics · Physics 2007-05-23 Janusz A. Gil , George I. Melikidze

Observations of the thermal X-ray emission from radio pulsars implicate that the size of hot spots is much smaller then the size of the polar cap that follows from the purely dipolar geometry of pulsar magnetic field. Most plausible…

High Energy Astrophysical Phenomena · Physics 2011-11-23 Andrzej Szary , George I. Melikidze , Janusz Gil

The unique and highly unusual drift feature reported for PSR J0815+0939, wherein one component's subpulses drift in the direction opposite of the general trend, is a veritable challenge to pulsar theory. In this paper, we observationally…

High Energy Astrophysical Phenomena · Physics 2019-08-27 Andrzej Szary , Joeri van Leeuwen

The partially screened vacuum gap model (PSG) for the inner acceleration region in normal radio pulsars, a variant of the pure vacuum gap model, attempts to account for the observed thermal X-ray emission from polar caps and the subpulse…

High Energy Astrophysical Phenomena · Physics 2020-01-08 Dipanjan Mitra , Rahul Basu , George I. Melikidze , Mihir Arjunwadkar

Pulsar electrodynamics could be relevant to the physics of stellar surface, which remains poorly understood for more than half a centenary and is difficult to probe due to the absence of direct and clear observational evidence.…

High Energy Astrophysical Phenomena · Physics 2024-01-26 Zhengli Wang , Jiguang Lu , Jingchen Jiang , Shunshun Cao , Weiyang Wang , Enwei Liang , Renxin Xu

The characteristics of the high-energy emission from polar cap accelerators will be discussed. Particles accelerated in the "slot gap" near the polar cap rim will reach altitudes of several stellar radii before initiating pair cascades,…

Astrophysics · Physics 2007-05-23 Alice K. Harding , Alexander G. Muslimov
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