---
author:
- 'M.I. Kudryavtsev'
- 'S.I. Svertilov'
- 'V.V. Bogomolov'
date:  
title: 'Transient pulsar dynamics in hard x-rays: Prognoz 9 and GRIF “Mir” space experiments data'
---

Introduction
============

It is well known that so called X-ray pulsars are associated with strongly magnetized rotating neutron stars (NS), which are characterized by great energy release as the result of accretion (accretion-powered pulsars) or rotation (rotation powered pulsars). The X-ray accretion-powered pulsars are generally divided into different classes based on the spectral type classification of the mass donor companion star [@Mer01]. The temporal behavior of such objects was always a problem of great interest for high-energy astrophysicists. Modern observations are usually made in a wide range of wavelengths from radio waves to gamma rays. While optical observations are in some respects more accurate, the observation of X-ray pulsars has provided an important information on the physics of NS, including the processes in the region of great energy release, and on the evolution of stars in binary systems.

The temporal behavior of NS binary system in hard X-rays reflects the physical processes in matter and fields surrounding NS. The properties of such matter and field determine quasi-periodic variations, while the rotation of 