Ladislav Bardos - Microwave Plasma Sources and Methods in Processing Technology

6 Chapter 6Figure 6.1 Schematic of planar microwave plasma system utilizing...Figure 6.2 Examples of high-density low-pressure plasma systems based...Figure 6.3 An illustration of the experimental system for testing the thrust...Figure 6.4 Illustration of the experimental system for production of hydrogen-...Figure 6.5 An illustration of the experimental system for the graphene...

1 Chapter 1 Table 1.1 Comparison of the loss tangent values of selected materials...

1 Cover

2 Title page Microwave Plasma Sources and Methods in Processing Technology Ladislav Bárdoš and Hana Baránková Uppsala University, Uppsala, Sweden

3 Copyright

4 Table of Contents

5 Foreword from the Authors

6 Begin Reading

7 Index

8 End User License Agreement

1 i

2 ii

3 iii

4 iv

5 v

6 vi

7 vii

8 viii

9 ix

10 x

11 xi

12 xii

13 1

14 2

15 3

16 4

17 5

18 6

19 7

20 8

21 9

22 10

23 11

24 12

25 13

26 14

27 15

28 16

29 17

30 18

31 19

32 20

33 21

34 22

35 23

36 24

37 25

38 26

39 27

40 28

41 29

42 30

43 31

44 32

45 33

46 34

47 35

48 36

49 37

50 38

51 39

52 40

53 41

54 42

55 43

56 44

57 45

58 46

59 47

60 48

61 49

62 50

63 51

64 52

65 53

66 54

67 55

68 56

69 57

70 58

71 59

72 60

73 61

74 62

75 63

76 64

77 65

78 66

79 67

80 68

81 69

82 70

83 71

84 72

85 73

86 74

87 75

88 76

89 77

90 78

91 79

92 80

93 81

94 82

95 83

96 84

97 85

98 86

99 87

100 88

101 89

102 90

103 91

104 92

105 93

106 94

107 95

108 96

109 97

110 98

111 99

112 100

113 101

114 102

115 103

116 104

117 105

118 106

119 107

120 108

121 109

122 110

123 111

124 112

125 113

126 114

127 115

128 116

129 117

130 118

131 119

132 120

133 121

134 122

135 123

136 124

137 125

138 126

139 127

140 128

141 129

142 130

143 131

144 132

145 133

146 134

147 135

148 136

149 137

150 138

151 139

152 140

153 141

154 142

155 143

156 144

157 145

158 146

159 147

160 148

161 149

162 150

163 151

164 152

165 153

166 154

167 155

168 156

169 157

170 158

171 159

172 160

173 161

174 162

175 163

176 164

177 165

178 166

179 167

180 168

181 169

182 170

183 171

184 172

185 173

186 174

187 175

188 176

189 177

190 178

191 179

192 180

193 181

194 182

195 183

196 184

197 185

198 186

199 187

200 188

201 189

202 190

203 191

204 192

205 193

206 194

207 195

208 196

After our long research and development activities in Plasma science we can state that the plasma is a well controlled environmentally-friendly medium utilizing electric power and enabling the very-high temperature processes and low temperature reactions not available in other methods. This book is, therefore, intended to help the readers interested in the non-thermal gas discharge plasmas and their applications. The content is focused on the microwave-generated plasmas, which have specific properties due to relatively high frequency and which can be used in a number of non-conventional applications. Based on our experience, from university teaching and from communications with the industry people, no broad understanding exists of the microwave power and the microwave plasma systems. People know microwave ovens, but mostly for the heating of meals, and without understanding the principles and specifications of the microwave power. Little knowledge exists about different plasma systems and applications related to microwave power, even though there is apparently growing interest in this technology, mainly for new plasma chemical processes. A motivation for writing this book is based on the authors’ long experience with design and applications of several non-conventional systems and applications, which might stimulate readers when furthering their knowledge and when developing new systems.

The content of this book is composed of five basic parts, i.e. chapters. Chapter 1is devoted to the microwave techniques and power systems from introducing their short history to the descriptions of individual parts and components in the microwave power lines, which are used in laboratory experiments and many industrial devices. Besides the microwave communication and the radar techniques, a lot of original systems have been developed for heating the plasma in fusion test reactors (Tokamaks, Stellarators, and Magnetic Mirrors), as well as in particle accelerators. Moreover, in the last two decades, interest has rapidly grown in microwave plasma systems working at atmospheric and higher pressures, in gases and inside liquids. Interesting new applications and trends are described in Chapter 6.

We have no intention to write a textbook and start with explanations of basic microwave theories based on Maxwell equations. Excellent comprehensive monographies have been written about microwave engineering with all theories, simulation models, and details, including use of microwaves for generation of the plasma discharges, see e.g. [Refs. 1–7]. However, to make it easier for the book readers without experience in the field of microwave engineering, we introduce the microwave systems in a simple way. We illustrate and describe the most important microwave components and show at least the most important expressions, which can help in greater understanding of the principles, functions, and applications of the microwave components. For these purposes we have also created a large number of original illustrations. Therefore, the text is frequently accompanied by schematic pictures, diagrams, and photographs. Such an approach was promoted and recommended long ago by the “Teacher of the nations,” Johannes Amos Comenius (Komensky in Czech) in his widely translated book “Orbis Sensualium Pictus,” issued in 1658. A copy of this book is available for example in the Hungarian library at the web address https://library.hungaricana.hu/hu/view/RMK_I_1091-RM_I_8r_0547/?pg=0&layout=s. Moreover, at the end of Chapter 1we have included Part 1.5 describing the microwave oven. This is because each oven represents a smartly engineered microwave system, which can help in the understanding of the basic principles and components in the microwave technology introduced and described in Chapter 1.

After an explanation of the functions of microwave components in the typical power lines for the microwave plasma generation, in Chapter 2, we describe the fundamentals of the gas discharge plasma and differences between plasmas generated by different kinds of the power, with particular emphasis to the microwave power. Chapter 3is devoted to explanations of interactions of plasmas with solid surfaces and gases, mainly at reduced and low pressures. Used explanations are simplified and limited to basic expressions and equations necessary for the understanding of the processes in the plasma and those caused by the plasma, as described in later chapters. Parts of the texts and some illustrations in Chapters 2and 3 are used in the authors’ courses for university students, short tutorials at companies and, since 1997, in annual courses for the Society of Vacuum Coaters ( www.svc.org) in the United States.