{'fraction_non_alphanumeric': 0.02782008325718347, 'fraction_numerical': 0.027921616407757133, 'mean_word_length': 5.099071207430341, 'pattern_counts': {'":': 0, '<': 0, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
History of solar wind and space plasma physics revisited

A paper published by Scottish geophysicist J.A. Broun in 1858 contained several pioneering and remarkable ideas in solar-terrestrial physics. He could anticipate more or less correctly the nature and origin of solar wind, solar magnetic fields, sunspot activity and geomagnetic storms in the middle of the 19th century. Broun applied the experimental results of the behavior of ionized gases in discharge tubes for the first time to Space Physics which may be considered as the beginning of the astrophysical plasma physics. In this context he attempted to explain the plasma interactions of solar wind with the comet tails and earth's magnetosphere. Most of the postulates or hypotheses put forward by Broun in 1858 and later in 1874 was rediscovered during the 20th century, after the advent of Space age.


Introduction
Emergence of physical ideas of solar wind and space plasma physics during the 20th century significantly contributed to our current knowledge of planetary sciences.
The quest for the causes of aurora and associations of the geomagnetic variations with solar phenomena like sunspots inspired the development of solar-terrestrial physics in the 18th and 19th centuries (Parker, 1989). Kristian Birkeland's Terrella experiments (1896-1913 were considered as the first study of that kind in space plasma physics (Rypdal and Brundtland, 1997). Ideas of transient particle emission from the Sun were developed since late 19th century (Goldstein, 1881;Mitra, 1952). However continuous solar wind flow from the Sun were actively considered by space physicists only during early 1950's (Biermann, 1951). We need to revisit the present history of solar wind and space plasma physics when we consider the scientific contributions of John Allan Broun during the 19th century.
John Allan Broun, the Scottish geophysicist and as-tronomer is well known for his discoveries of semi-annual variations in geomagnetic activity (Broun, 1848) and solar sources of recurrent geomagnetic storms before Maunder (Broun, 1876). Broun served as the director of Matherstom magnetic observatory in Scotland during the years 1842-1848 and Maharaja's observatory in Trivandrum during the years 1852-1865 (Clerke, 2004). During his service in Trivandrum (situated near magnetic dip equator) J.A.
Broun wrote a remarkable paper in December 1857 which was published in Philosophical Magazine as a letter next year (Broun, 1858). This was one hundred years prior to the publication of the hydrodynamic theory of the solar wind (Parker, 1960).
In this article we will discuss first about the pioneering ideas of Broun contained in the above paper about the nature and origin of solar magnetic fields and sunspot activity at a time when solar physics was just emerging as a research discipline. We will also explain how Broun perhaps opened the studies on astrophysical plasma physics when he applied the experimental results of electricity and magnetism (gas discharge tube experiments) to space physics.
The nature of solar wind type medium filling the interplanetary space and its interaction with plasma bodies like comets and earth's magnetosphere as envisaged by Broun in his paper (Broun, 1858) during the middle of 19th century will be then discussed. It is interesting to find that experimental confirmation to Broun's postulates/hypotheses in 1858 and later in 1874 could be possible only during the second half of 20th century with the advent of space age.

Broun's ideas of solar magnetic fields and sunspot activity in the year 1858
After the discovery of sunspot cycle (Schawabe, 1844) the attempts to connect sunspot activity with geomagnetic phenomena was purely statistical or empirical in nature and lacked physical models to support the same. In order to explain certain laws of geomagnetic variations observed in Europe and Trivandrum, Broun proposed some new ideas about sunspot activity and solar magnetic fields with some physical insight in his Philosophical Magazine paper (Broun, 1858). The relevant portions from the text of the above paper will be cited below (given within inverted comas). We have given our explanatory notes in the modern scientific perspective for each citation which are numbered serially in the small Roman numerals. The page numbers refers to the original paper of Broun.  Stewart and Loewy, 1872). This is also a topic of current interest (Hung, 2007).
Planets in our solar system are known to revolve the sun in orbits situated close (within ten degrees) to the heliographic equator (Novotny and Fairbrid 1967).
(iii) "page 95: If the sun act as a magnet it is possible from the analogy of our earth, that its magnetic poles will not coincide with the poles of rotation; perhaps even the poles may have unequal forces. In such a case, it might be expected that the fact could be determined from our magnetic observations." • Broun's remarkable and intuitive perception of the nature of large scale solar magnetic fields.
During sunspot minimum and declining phases of the sunspot cycles large scale solar magnetic fields often resembles a tilted dipole configuration (Shultz, 1973;Zirker, 1977). North-south asymmetry in the strength of solar polar magnetic fields and differences in the epochs of reversals in northern and southern helio hemispheres are well documented in the solar-terrestrial literature of recent times (Babcock, 1959;Makarov and Makarova, 1996). Broun's idea of inferring properties of solar magnetic fields from geomagnetic data is also acceptable in the modern cotext (Lockwood, Stamper and Wild, 1999;Love, Rigler and Gibson, 2012).
3. Beginning of astrophysical plasma physics: Broun's ideas of solar wind and its interaction with comets and earth's magnetosphere.
Studies on the electric discharge lamps and electric arcs (Crowther, 1969;Maecker, 2009) inspired the investigations on the discharge of electricity through rarefied gases in the 19th century (Thompson, 2005). This later contributed to the development of atomic physics and plasma physics. J.A. Broun was perhaps the first physicist to apply the results of discharge tube experiments in electromagnetism to space physics which may be considered as the beginning of astrophysical plasma physics. In this section we will describe about these pioneering ideas of Broun published in his philosophical magazine paper (Broun, 1858). As in the previous section citations of relevant passages on the above paper will be presented here with our brief explanatory notes. to the satellite era during which it was experimentally confirmed (Biermann, 1963). • Eventhough several models of the possible interactions of solar wind particles with earth's magnetic field were developed during the first half of the 20th century (see Mitra, 1952, for details) the deformation of the earth's magnetosphere from the dipole geometry (day side compression and extended magnetic tail) due to interaction with the continuous solar wind flow was not known until the spacecraft age (Kivelson and Russel, 1995). But Broun could anticipate this discovery at least hundred years prior to its experimental confirmation. He could also infer that the physical mechanisms behind interaction of extended solar magnetic fields (carried by the solar wind) with comets and earth's magnetic atmosphere are identical or similar in nature.
It is well known that search for the physical nature of cathode rays lead to the discovery of electrons by J.J. Thompson in 1897(Thompson, 1897. Actually cathode rays was discovered much earlier through pioneering experiments carried by (Plücker, 1858) on the action of external magnetic field on rarefied gases in discharge tubes. The shape of light glows in these discharge tubes (Geisslers tubes) used by Plücker for the above experiments surprisingly resembled the shape of earth's magnetosphere (see   (Akasofu, 1981).
It is quite interesting to find that Broun could anticipate long ago (in 1858) that geomagnetic storms are indeed part of a huge energy dissipation phenomena in the earth environment involving strong or violent physical interactions.

Discussion
Several decades prior to the dawn of modern atomic physics and plasma physics, Broun could propose several pioneering ideas in solar-terrestrial physics which were rediscovered during the 20th century (Table 1) for the solar wind outflow from the sun which is cited below (Broun, 1874).
"I believe the facts now certainly connected with solar and lunar magnetic action cannot be explained without the existence of an electric medium similar to through it may be denser than in which light and heat are propagated.
As a footnote: The idea of such a medium was sug-  Shuster (1905) 3. Nature of large scale solar magnetic fields:-(a) origin due to an electromagnetic induction process in the sun Dynamo theory of Larmor (1919) (b) tilted dipole configuration (Shultz, 1973) (c) north-south asymmetry in solar polar magnetic fields (Babcock, 1959) 4. Solar wind and IMF plasma interactions: (a) with earth's magnetosphere causing distortion in shape Explorer satellite observations (Kivelson and Russel, 1995) (b) with comet tails Biermann (1963), Neidner and Brandt (1978), Neidner (1982) 5. Geomagnetic storm as a significant energy dissipation phenomena in the terrestrial environment Solar-wind magnetosphere energy coupling models Akasofu (1981) gested by Herchel in 1843 (see for eg. Steven Ruskin, 2004).
It is quite possible that there may be denser medium around the sun. I have long ago suggested that the zodiacal light is formed in this medium by the passage of electric fluid (Broun, 1858). If M. Fayes theory of the repulsive action of solar heat, which blows out the cometary gases so many millions of miles could be assumed the same action should blow off a part of solar gases."